The look of natural flagstone set in grass can be beautiful if done correctly and used in the right situation.

The turf in-between the stones softens the overall look of the path which can help distinguish it from other primary walkways.

At the same time this technique can subtly  connect different “points” in the landscape and direct the eye and traffic.

From a practical standpoint the stone path gives everybody a clean, solid surface to walk on in the event the grass is wet and/or soft.

The process of installing a path like this will vary slightly depending on circumstances such as the condition of the existing lawn.   Or, perhaps there is no lawn to begin with and you want to achieve this look.

The following installation will show the fundamentals.  

Flagstone Quality And Layout Are Important

Choose a type of flagstone that is dense and solid.  Stay away from slates and other types that flake, fragment and deteriorate over time.

You want the majority of pieces to be larger in size and no less than 1.5″ thick.  The idea here is that greater size and weight give stability – this is key.

Purchase and layout a good selection of flagstone so you have pieces to choose from.  Notice how plywood is used to protect the paver driveway.

Before you begin the actual site work and preparation, arrange the stones on top of the existing lawn how you would ultimately like them to look.

In this picture below, the stones are set and ready to be installed.  The homeowner requested that the space between the stones be kept close.

Compare this to the first photo at the top.  This is a different project where spacing was made slightly wider.

Keep in mind the spacing must be wide enough to support the living grass.  Arrange the flagstones no closer than 1.5 – 2.0″ apart.

Preparation And Installation Of Flagstone

The next step after arranging the flagstones is to prepare the base for installation.

Step one, removing the existing lawn, was fairly easy on this job.  The grass happened to be recently planted sod and was not yet deeply rooted.

Working in sections, move 3 – 4 stones at a time off to the side.  The sod can then be peeled back and the stones replaced to their set positions.

Realize, of course, that if you had a well established lawn, removing it would most likely involve some other strategy.  Again, which tactic you use to remove the grass depends on the circumstances.

With the flagstones now sitting on bare ground, you are ready to prepare the base on which you’ll set the stones.

Trace the outline of the stone on the ground with a pointed tool of some sort – a trowel works fine.  Using a spade dig down 5 – 6″ within the outlined area.

In this excavated space install 3 – 4″ of crushed gravel.  We like to use gravel no larger than 1/4″ diameter.  It’s small enough to “move & level” with a trowel, compacts well and drains nicely too.

Now sometimes it gets difficult during this base preparation to preserve the narrower strips of earth between stones.  The key is to preserve or replace soil in these narrow strips so they can support grass.

If it becomes too difficult to preserve these narrow strips of soil and they combine with the gravel base, take care to ultimately fill these voids with as much soil as possible.

For grass to survive in that narrow space, it must have a deep root system in soil.

A flagstone path in a lawn is meant to be informal.  Although you can see line design and pattern, there is still irregular shapes in the stone.

The pattern, which unifies the path, is achieved by relating the shape of each stone to one another.

Sometimes, no matter how much stone you have to pick from, you simply can’t find a good match.  This is the time to create the shape yourself by cutting the stone.

In the picture above we’ve arranged the path to widen at the top of a stairway.  Unable to find a stone to fit the situation, we overlapped one stone over another.

Before making the cut we first mark a line on the bottom stone.  This line mirrors the shape of the stone above with a 2″ space.

The cut is actually made with a diamond blade.  Although diamond blades can be fitted on different types of power saws, here a 2 stroke cut-off saw was used.

After the cut is made the fresh-cut edge is “distressed” with a mason’s hammer to make it look more natural.

This last picture also shows a string-line set up.  The string is set at an equal height from the “finish grade” at each end of the walk.

You can check the uniformity of height and pitch of your walk by referencing this line at any point.

Realize, however, that there are times when your walk’s finished height may have to follow a particular grade contour that is critical for drainage.  Again, this is a particular circumstance you’ll have to identify on your site and adjust to accordingly.

The basic tools for actually setting the flagstones are a mason’s trowel and rubber mallet.

The trowel lets you move and adjust the gravel base while the rubber mallet lets you tap the surface of the stones to set them firmly.

As mentioned, the string line is helpful to check your walk’s height and pitch.  A tape measure is used constantly.

And last but not least, a bubble-level is important to check each stone.  By bridging the level from one stone to the next you can check the “height / pitch” relationship of one stone to the other.

  • katrina
    8:11 PM, 6 March 2010

    Hi – this is very helpful. you have a nice way of explaining things. my husband is going to lay flagstone path like this in our backyard. we don’t have grass there now. Don’t you need to set the stones in cement so they don’t move around when you walk on them? Won’t they be wobbly? Afterward, should we just lay sod around the stones? Thanks!

    • Roger
      10:11 PM, 6 March 2010

      Concrete is not necessary if you’re using large and thick enough pieces of flagstone. Most of these pieces on this project are handled by two men and even the smaller sizes are quite heavy (for one man). This is so important in “dry-set” work like this. Weight & Mass = Stability.

      As I mentioned, you can use a 1/8″ crushed stone, but even a coarse sand would work. We find the crushed stone drains well and this is important. If you live in a cold climate, moisture built up under the stones will cause them to “heave” in the freeze – thaw cycle. Using a setting-base like small crushed stone, sand or similar, enables you to support the stone evenly so it doesn’t wobble when you step on it. You may find yourself lifting, re-adjusting the base material (to fit the shape of the bottom of the flagstone) and re-setting the stone a few times before getting it nice and stable.

      Perhaps if the flagstone pieces you intend to use are small and thin you could use concrete to set them in. The concrete might bond with the thin flagstone and function like a thicker, heavier mass to give stability. I’ve never done it that way so it’s hard to say.

      And yes, sod would then be installed around and in-between the stones. Established grass will also help to stabilize the flagstone and keep it from moving and shifting. The grass will actually grow over the flagstone edges a bit in time. Therefore, we do trim back the grass occasionally to keep the majority of each stone exposed.
      Hope this helps. Let us know how things go.

  • Kevin
    2:39 PM, 4 May 2010

    I have established grass in my front yard and would like to run a small flagstone path from my small side garage door over to my front driveway so that my golfcart won’t make tracks in the yard. Can I get away with not having to put any concrete under the stones? Also if I get thick heavy stone will they hold the weight of a golf cart. It won’t be used that much (maybe once or twice a week).

    • Roger
      9:55 PM, 4 May 2010

      The 2 most important things to create this path are the base preparation and the thickness/strength of the stone. Concrete is not necessary.

      Decide on how the path should be configured. Are you thinking of a single width path that is wide enough for the entire cart, or perhaps 2 narrower paths running parallel with grass in between?

      Remove the sod in the area(s) you’ve determined for the path(s). Now excavate down and remove enough earth to allow for 4″ of compacted base, plus the thickness of your flagstone. This “compacted” base could be 3/8″ crushed stone or “quarry process / binder”, which is what goes under asphalt roads and driveways. Home Depot carries material like this in bags.

      Try to use thick, large pieces of flagstone. 2″ thick would be my choice, and no less than 18″ wide. The larger and heavier the stones the better they will set (and stay put). It’s important to adjust each stone so they sit level with the surrounding grade. Take time to adjust the base material under each stone to eliminate any wobble. I would fit the stones so that the “joints” from one stone to the next were minimal. They now make special joint sand for filling in this space. I’ve also used a material called “stonedust” for jointing.

      On the outside edges of your path the lawn should be restored right to the stone so the grass and its root system knits and helps secure the flagstone even further.

      This could be a nice, natural look that provides a solid surface for the golf cart. These stones will obviously be heavy to work with. Take it nice and easy and a helper would be great for lifting. This is the kind of job you can do in stages too.

  • Ron
    5:26 PM, 7 July 2010

    What is a reasonable price for a bluestone path with grass joints installed in Michigan? SQ foot cost?

    • Roger
      9:50 PM, 8 July 2010

      I don’t know the pricing in Michigan, but here in northern NJ I would figure somewhere around $18 – $20/sf. This is assuming the process is complete in terms of base prep., good quality bluestone that’s at least 1.5″ thick, and care is taken in arranging, fitting and cutting the stone if necessary. Also, as I had mentioned, avoid using smaller pieces.

      Hopefully whoever is offering to do this job for you can show you other walks they’ve done. Then you can say: “Yes, I like this walk and I would like mine to look just like this.” You might enjoy this article on “terminology and expectation”
      Take care,

  • Judie
    2:41 PM, 16 July 2010


    Great article – thank you!

    I’m starting from scratch and am wondering about the right steps to follow when a) I’ll be putting in a new lawn and b) I’d like to put in a flagstone path around the perimeter of the lawn. The flagstone path will also serve as a transition of sorts between the lawn and the raised beds that run the perimeter of my back yard. I’d like the joints between the flagstone to be filled with lawn, as shown in this article.

    I’m wondering if this plan would make sense:
    1. Excavate as necessary and backfill pathways with 3-4″ gravel
    2. Place flagstone in desired configuration
    3. Prep lawn area for new sod
    4. Fill gaps between flagstones with soil, leaving space for sod depth
    5. Lay sod in lawn
    6. Cut strips/pieces of sod and place between flagstone

    Are there any flaws in my logic?

    Many thanks,


    • Roger
      12:34 PM, 17 July 2010

      Great idea and look! Just a few comments:

      To some degree your flagstone path/border will establish a permanent edge to your gardens. I would review all the plants (particularly the woody shrubs) that will be within close proximity to the border because as they grow and mature you really won’t have the flexibility of a grass border/edge that you can simply make bigger and bigger. Sure it’s OK for the shrub(s) to grow a little over the flagstone edge, but many people don’t realize the growth potential in their plants.

      You can use 3/4″ gravel as a “lower base”, but leave enough room for a smaller gravel size on top to make it easier to adjust when leveling the flagstone. Or, just use the smaller gravel throughout.

      Are there or will there be in-ground sprinkler heads? If they’re existing it’s not a problem – you’ll simply work around them and set your flagstone accordingly. If you’re planning to install underground sprinklers, try to integrate that during the prep work so you don’t have to disturb work you may have detailed and finished.

      Make sure when you place soil between the flagstone for the grass you remove enough gravel so the grass has as much soil as possible to establish in. Between the heat retention capacity of the flagstone (from the sun) and then the fast-draining aspect from the gravel beneath, this grass needs all the help it can get.

      Good luck with this. I’d love to see a picture when it’s done.


  • Kim
    10:36 AM, 24 August 2010

    How did you move the flagstone around?
    My pieces are 2″ thick 2′ x 3 1/2′ in size. I estimate they weigh about 300 lbs each.
    Do you think I will have to rent a machine?

    • Roger
      11:28 PM, 24 August 2010

      Hi Kim,
      Now that’s what I call a nice piece of flagstone!

      I feel your pain. Moving these stones around is not easy. To handle the piece you describe without power equipment, I would have 2 men, a hand-truck, and a wheel barrow. If you use the hand truck realize that when you lower the handles with the stone on it, a good amount of the stone’s weight is going to be on the handle-end of the hand truck. If you use the wheel barrow, lift the stone (with 2 men) and “bridge” the 3 1/2′ length across the outer edges of the wheel barrow. Make sure the weight is evenly balanced before lifting the handles to move the stone.

      The other issue with weight is when you’re setting the stone and leveling it. Inevitably you’ll have to lift it a few times to adjust the “setting bed” (i.e. 1/4 – 3/8″ crushed stone) underneath. You can simply lift the stone so it’s standing on its edge, have one person hold it upright while the other adjusts the setting bed. Then, use both people to slowly lower the stone down.

      We sometimes use braided wire cables to lift and maneuver the larger pieces. For your situation you would have 2 lengths of cable – perhaps each 15′ long (maybe 1/8″ dia.). Situate the flagstone so its laying on the 2 lengths of cable running parallel to each other. With this method you need 4 people…one at each end of the 2 cables. The 4 of you will lift the stone into position using the cables. The cables will not really affect the leveling and setting of the stone. Leave the cables in place to continue lifting the stone and adjusting the base gravel until it sits the way you want it. When set, simply pull the cables out from under the stone.

      Please be careful. Watch how you lift (use your legs, not your back). Hope this helps.

  • Ben
    5:29 PM, 24 September 2010

    Do you think a pathway for a vehicle (leading from cement pad on side of home to the roadway) with this type of pathway would be practical. It would not get used very often as I store a boat on the pad, but don.t think I would like the look of pouring concrete all the way to the road

    • Roger
      9:08 PM, 2 October 2010

      We’ve actually set flagstone as a “driveable” surface. These are some of the key points if you intend to put vehicle weight on the stone.

      1) Flagstone like this should be at least 3″ to 4″ thick. Yes, that would make them very heavy. 2) The base you prepare for them is critical. I would excavate 8 to 10″ down and fill to within 4″ of finished grade with 3/4″ crushed stone. If you can compact any disturbed earth and the gravel as well, this will minimize (or ideally eliminate) any “give” or settling. Any give or settling in the base will jeopardize the flagstone on top. 3) Now use a finer gravel (1/4 to 3/8″) on top of the compacted 3/4″ gravel as a “setting bed” to level and place the flagstone. Make sure the flagstone is sitting solidly on the finer gravel bedding so that vehicle weight on the flagstone is well-supported.

      Alternatively you could excavate for the flagstone, compact the earth at the bottom, pour a 4″ or greater concrete slab (leave a “rough” surface”), let that set and harden, and then set the flagstone with mortar on the slab. The flagstone could then be 1 – 1 1/2″ thick.
      Hope this helps, Ben.

  • Keith
    8:04 PM, 14 October 2010

    Roger –

    First of all, great article. Very instructive.

    What advise do you have for someone who is trying to achieve this look, but has not yet laid sod in the area where the path will go (it’s barren ground right now)? I’m most interested in understanding what the easiest installation would be.

    Lay down gravel over the entire path area first and dig out areas between flagstones later to allow for soil and sod? Or only put gravel under only the spots where flagstone will go and avoid digging out “grout” areas later?

    Thanks for any insight!


    • Roger
      9:06 PM, 14 October 2010

      Hey Keith,
      Since you’re going to be laying down sod, make sure you allow for the extra thickness the sod will add to the existing bare earth you have now. If you think in terms of the sod’s root system thickness, it usually adds another 1.5″ or so. That 1.5″ height above your existing bare dirt should be the finished height of your flagstone. Keep that in mind when you’re setting your flagstones.

      With regard to your question about “the process,” it really depends on the space you decide you want between the stones (a.k.a. joint space). If the space is generous (say 5″ or greater) you could treat each stone separately. In this case you’d mark where each one is sitting (always lay out the stones first so you establish the pattern and spacing) and then dig out underneath each stone, install your base material (1/4 – 3/8″ gravel) and set the flagstone. Now you have the existing soil remaining between each flagstone ready for the sod strip you’ll install.

      If your spacing the flagstones closer, it’s more efficient to treat the path universally and prepare the base throughout the area. Now you can set your flagstone pieces fluidly going from one to the next. As you had mentioned, when you’re done go back to the joints and “rake-out” a few inches of the gravel with a narrow tool. Fill in the void with soil and pack it in firmly. Now you’re ready for your (narrow) sod strip. I have a narrow mason’s jointing trowel (maybe 1/2 – 5/8″ wide) that’s perfect for removing the gravel from those narrow joints.

      This time of year is good for this because it will be relatively easy to keep the grass strips and new sod moist. Of course that depends on where you live. If it’s hot, be diligent with watering.

      I hope this helps, Keith.

  • Keith
    11:31 AM, 7 November 2010

    Thanks Roger. I’m finally getting the ball rolling on this. One additional question if you don’t mind.

    Think I can get away with 1+ inch Oklahoma flag? I live in central Texas (mild winters, firm soil). I know, it’s not quite your recommended thickness, but trying to see if it will work anyway.

    Thanks again.

    • Roger
      11:41 AM, 7 November 2010

      Sure, Keith. One inch flagstone should be fine for a “walking path”. Again, try to keep the flagstone pieces as large as possible. The size and mass will help to keep it stable and in place. The sod work that ultimately surrounds each piece will also help in the stability area.

  • Thomas
    10:57 PM, 21 December 2010

    Great information Question -is there ever an application where you can lay the flagstone directly on the grass and have success with smaller paths say 10 to 15 feet?

    Appreciate the help

    • Roger
      8:28 PM, 22 December 2010

      If you set the flagstone directly on the grass it will be protruding above the grade. This will be a tripping hazard and get in the way of the lawn mower. Also, the flagstone will not be stable and secure as it would be if “recessed” in the ground.

      If you’re looking to simplify the whole process, how about just removing the grass and enough soil where each flagstone will sit so that the stone is flush with the grade? Essentially you’re omitting the “major” excavation work and gravel base. But at least the flagstone will be recessed and not a tripping hazard.

      If your ground is hard and rocky, you could over-dig a bit and then use a little sand to set and level each stone.
      Hope this helps.

  • Thomas
    11:58 PM, 28 December 2010

    Makes sense Roger-Thank you for the follow up and I will take your advice and recess the stones-a wonderful new year to you!

  • Jennifer
    1:50 PM, 10 January 2011

    Very helpful! I have a similar question to Thomas. I want to create a walkway about 10 feet long from my back steps to my patio. I already have sod growing in the area but it gets muddy in the rain – hence wanting a walkway. My problem is that I have a drip irrigation system under this area and if i have to dig down into the irrigation system and find all of the tubing the job will be much more difficult. I was hoping to just put the stones in the ground but not have to dig too far down because of the irrigation system. The irrigation system is about 2.5-3″ under the sod. Do you think if I just dig the sod out of the areas I want the stones, lay a little sand down I can get away it? I do want grass to grow between the stones so maybe I could stick some of the sod back in between the rocks? Do you see a problem with an irrigation system being underneath? Thanks!

    • Roger
      7:36 PM, 10 January 2011

      Hi Jennifer,
      Is the area chronically wet? You mentioned it gets muddy during a rain, but I’m curious if the area drains well. Is there pitch to the grade so the water moves off the lawn? Is the soil porous so it drains, or is it dense with clay content so it doesn’t drain?

      I don’t have any experience with drip irrigation in a lawn area – only planting beds. However, I am familiar with it from reading and what I know of drip irrigation in general. Make sure you “manage” the amount and frequency of the drip irrigation. Adjust the controller seasonally so the lawn is getting just enough water to keep it healthy. Does the system have a rain sensor or other sensing device so it does not water when it’s really wet or raining?

      With regard to the flagstone path, I think you could get away with just digging down enough to fit the flagstone with a little sand or gravel (1/4″ to 3/8″). Again, the goal is to get the stone close to “flush” with the grade. The small gravel may be a better choice than the sand because it may handle the wet conditions better.

      If the drip irrigation tubing is 2.5 to 3″ down, you should have just enough room to fit a thin layer of “setting” sand (or gravel) and the flagstone. For a simple pathway this should be fine.

      You could check with the irrigation company that installed “the drip,” and ask about allowing the tubing to remain under the stone. They may suggest plugging the emitter holes in some way, or possibly replacing the perforated pipe section with a piece of “solid” pipe (not difficult). I myself would probably stop the water from the drip system directly under the stones by one of these 2 methods.

      Be careful not to compress the drip irrigation tubing with your flagstone. As long as the tubing is surrounded by sand or gravel (or below that level) the tubing should be safe. You want the weight of the flagstone to be supported by the sand, gravel or earth and not the tubing.
      Good luck, and I’d love to know how things turn out.

  • Jennifer
    11:50 PM, 10 January 2011

    Thank you, Roger for the great answer. I live in Southern CA so the area is only wet during the winter and we have had a lot of rain during the past couple of months. Nine months of the year it doesn’t rain so as long as I don’t overwater it, it isn’t usually muddy. However now I have patches where grass used to be and either the dog or the kids squished it away with their feet, leaving soft mud/dirt – one of the reasons I want a pathway. I agree it might be better to get those irrigation pipes plugged up but I think that might be too big a job for me. I’m afraid I might did up too much just trying to find the lines and make a big mess! The lines run vertically and I want my path to have a diagonal direction which also complicates taking out some of the lines. I will definitely let you know how it goes 🙂
    Thanks again!

  • Thomas
    1:47 AM, 11 January 2011


    Once again thanks for the guidance. The paths turned out great. The key to setting the Flagstone was the base layer of sand. No getting around that step.

    Backyard is incredible and the Flagstone turned out to be a work of art.

    Best in the new year

  • Helen Mottley
    12:04 PM, 27 January 2011

    You have great information on designing and installing flagstone paths. I have a question. I have flagstone already to be installed but my yard does not have any grass. It is dirt but very level. I am not planning on having any grass. I want to use the sand as a filler between the stones. What do I need to do to prepare my ground since I don’t have any grass? Thank you

    • Roger
      2:40 PM, 27 January 2011

      Since you’re not installing grass and, therefore, not having to mow, it may not be that important that the flagstones are “flush” with the ground. I still would excavate some of the earth beneath each flagstone and replace it with a base/leveling material like 1/4″ gravel. You could use sand too, but I prefer gravel because it does not hold moisture. It sounds like you plan to use sand to “joint” in between the flagstones once they’re set – that should be fine, but weeds will grow in sand. We often use “stonedust” for jointing. A stone/mason supply yard would carry that. It compacts really well, almost like cement, and weeds are less likely to grow in that. They also sell a polymeric sand used specifically for jointing. This we find works well too.

  • Lorraine
    9:03 AM, 14 April 2011

    Great info! We are laying a flagstone path in soil and will be growing a lawn from seed. Should the stones be laid flush with the soil or a little higher? My husband started levelling them last night to be flush with the soil and is now thinking they should be higher to accomodate the grass once it grows.


    • Roger
      1:06 PM, 14 April 2011

      Hi Lorraine,
      When we do a seed lawn with flagstone, we set the stones “flush” with the soil. This will ensure the stone does not protrude and cause a “trip hazard”. Plus, you want he wheels of the lawn mower to roll smoothly when they come upon the path.
      Take care,

  • Scott
    3:03 PM, 12 May 2011

    Thanks for the information! I’m considering putting some portage stones in my back yard to make a path and was wondering if you could give me some insight. I have a couple of flower beds in back (raised ~3″) that the path will run between. Unfortunately, this is an area that gets washed out with heavy rains as it slopes from left (top) to right (bottom). I have neighbors on both sides, so I can’t simply install drains at the top and bottom. The path area is ~3′ wide by 25′ long and drops 1+’ in elevation from top to bottom. My current “plan” is to have a base layer of gravel (not sure what size) with a layer of sand (not sure what size) on top of it and the stones (16″x21″, 36lbs) on top of them with a few inches of space between each stone and river pebble between the stones. This way, the water carrying dirt, etc from the neighbor to my left will flow over the path without depositing the dirt in my yard and washing my dirt, pebble, etc away. Do you think this will work and do you have any recommendations for gravel/sand size and thickness or any other ideas? Thanks again!


    • Roger
      10:05 PM, 12 May 2011

      You’re on the right track. I would excavate approximately 6″ down from finish walk height. You should then have 4″ for a base of 3/4″ crushed gravel. You should lay down filter fabric on the dirt sub-base and then the 3/4″ gravel on that. This will ensure the gravel does not mix and migrate into the soil sub-base. This is especially important considering the runoff problem you’re trying to manage.

      On top of the 3/4″ gravel lay down about a 1″ layer of 3/8″ crushed gravel as your “stone setting” material. I would not use sand. If “run-off” is a problem sand will not stand up to that.

      The river pebbles sound nice for the joints. And now you have an entire walkway made of stone and porous gravel. This should work fine.

      I’m a little concerned that you said “water carrying dirt” from the neighbor. If that water is carrying dirt and debris it may deposit some of it within your walkway. I wish there was a way for you to divert or even “filter” that dirty water before it hits your walk.

      Let me just mention one other strategy that we’ve done in similar situations with walkways and “runoff”. If the runoff is really severe in heavy rains, incorporate a perforated drain pipe within the 3/4″ gravel base. There is rigid and flexible perforated pipe, and you can get it in 3″ diameter. Of course it has to be pitched, and I would wrap it in filter fabric, or they actually sell a “filter sock” that goes over the pipe. This will keep out silt and debris from entering the pipe.

      If you think there’s enough water entering this walkway, the perforated pipe might be something to consider adding. You’re excavating for the 3/4″ gravel base anyway, and that’s the hard part.

  • Harrison
    3:11 PM, 25 June 2011

    I have existing lawn and wanted to install about 90 feet of flagstone path with grass joints. The flagstone is about 1.5 inches thick. I’m thinking the easiest way is to use a sod cutter set at about 2 inches to cut my path. Then roll up my sod. This should leave a good outline and flat surface in the soil. I would then place flagstone in position and fill around each with topsoil and seed. Any reason this is not a good plan. Any suggestion would be helpful. Thanks, Harrison

    • Roger
      10:21 PM, 25 June 2011

      No problem calling me Scott. I like the name.
      The reason we use gravel underneath our flagstone paths is for drainage, which helps reduce “heaving” from the freeze/thaw cycle of winters. The finer gravel we use as our top layer also helps with drainage, but also gives us a medium for leveling and stabilizing each stone as we set them.

      If you’re not concerned about overall drainage and “heaving” (if you live in a cold area), then you’re probably OK with your strategy. Perhaps you could lower the soil level under each stone just so there’s room for a layer of “setting material”. I say this because it might get frustrating setting your flagstone down and having them wobble or not be the right level/height. An inch or so of “setting material” could make the process (especially over 90′) of setting each stone that much easier. The setting material could be a coarse sand or a fine gravel.

      Also, I’m not sure how good the sod is you’d be removing, but what about the idea of using it to fill in between the flagstone? If the sod is poor then it probably makes sense to use top soil and seed to restore the grass.

  • Luke
    11:43 PM, 27 June 2011

    Hi there,

    I have some very thick and heavy flagstone’s (2-4 inches thick) that I will be installing in my front lawn space.
    The path is going to be from my front step curving right to my driveway (triangular shaped) I’m not sure if the flagstone whould be better off to be flush with the driveway, or have it a little above the driveway? I think there will be a little slope needed from the grass to the driveway (left to right)
    The main thing is what materials are best for this job for the foundation… I do want to do this the right way and do have a little experience.
    I am not quite sure how deep to dig the foundation in order to support these heavy flagstones so they are good and level. Some of the flagstones are bigger in the middle than others. So I’ll need something in the centre that is workable to twist and turn them till they are good and sturdy. What materiel would you suggest I use. I need to know how deep to dig down in inches, how much screenage I need to tamp in first.
    I will use some edging between the grass and flagstone to keep the grass out and weed barrier to keep the weeds out.

    I appreciate your thoughts and help!
    Thanks, Luke

    • Roger
      4:26 PM, 28 June 2011

      Nice flagstone! They will make a solid walk once installed. Watch your back handling them.

      It seems as though you will have no grass growing between each flagstone, and that’s fine. Evidently you’re planning on some kind of edging to separate the lawn from the walk area. So perhaps a decorative gravel used in between each stone in the path would look (and work) nicely.

      In terms of the height of the flagstone I would try to keep all the elements (flagstone, decorative gravel joints and edging) close to flush with one another. Nothing should be sticking up higher than the other. Therefore the overall surface is without obstruction. It will look nice and seamless, and less likely to trip someone. Even the top of the edging should be close to level with everything next to it. Think of the edging as just a divider between elements, not a higher barrier.

      If you excavate 6″ down you’re guaranteed enough room for setting even the thickest of your flagstones. I’d recommend using a small crushed gravel (e.g. 1/4″) as the base and setting material. It will drain well, compact well and is nice to work with when adjusting the setting bed for each stone’s irregularities.

      Hopefully each piece of flagstone you have is big enough (in terms of area) so that it doesn’t shift or move. Thick is good, but they should be dimensionally wide and long as well. If you set the stones so they are flush with the surrounding grade, and then joint in-between with the decorative gravel, they should be pretty well stabilized in their positions.

  • Luke
    10:54 PM, 28 June 2011

    Hi Roger:

    Thank you for making it sound so much easier!

    So I will escavate 6 inches down now and for sure have some extra help lifting!

    Should I put the weed barrier down first before I put 2 to 3 inches of 1/4″ small gravel down? Than put some more on top if needed and repeat that process.
    I was wondering if I should leave the top layer of 1/4″ small gravel looser at the top so I can press and adjust the flagstones into it to fit properly or just make sure it’s tightly compacted thoroughly before laying?

    Thanks, Luke

    • Roger
      12:45 PM, 29 June 2011

      Yes, put the weed barrier at the bottom and then the gravel. We compact the earth (sub-base) after we excavate because that earth has been loosened. Then place your weed barrier, etc.

      Compaction is important so I would go ahead and compact the gravel as you go. Since the gravel is fine (1/4″), the top should loosen relatively easily with a trowel as you set each stone. If you find it’s easier, compact the first base layer of gravel (2″ or so) and then add the “setting” layer on top of that to work with.

      I’m not sure what you’re using to compact, but even a hand tamper would do the job for a walkway like this.

  • Luke
    1:35 PM, 29 June 2011

    Hi Roger:

    I will probably use a gas powered plate tamper and a hand held tamper for the edges. I’m just not sure what type of edging material I should use for the side of the path that will be facing the grass. The other side will be pretty flush with the driveway.

    I really do appreciate your experties.

    • Roger
      8:52 PM, 29 June 2011

      Hi Luke,
      In your particular application you’ll want an edging product that will keep the gravel in-between the flagstone joints separated from the grass. As I mentioned in a previous comment, the top of the edging should not stick up higher than the flagstone and grass. Keep all elements level with one another.

      I would use a flexible aluminum edging product like from Permaloc. You can adjust the height when you’re installing it to follow the top flagstone level. They manufacture several types of landscape edgings. You should probably locate a supplier near your area (use their website to help find one) and then visit the supplier to see the various choices.

      Aluminum might cost a bit more than plastic, but it has it’s obvious advantages in terms of quality and durability. You might find that if you live in a cold climate the edging may “heave” a little from the freeze/thaw of winter. It’s fairly common and Permaloc has these nice long support stakes that help minimize that. If the edging does rise a bit (heave) from the winter, just use a scrap piece of wood and a hammer (or maul) to knock it back down.

      Good luck with your project!

  • Harrison
    12:55 PM, 10 July 2011

    Just as a follow up. I used a sod cutter for my path and it worked great. It cut 2.5 inches of dirt under the grass and I was left with flat solid surface to work with.
    Thanks Harrison

  • Peter
    10:31 AM, 11 August 2011

    I want to lay flagstone at the side of my house as a pathway to the backyard.

    How do I handle any grading issues as I still want the water to drain away from my house. If I install the flagstone on a slight angle instead of completely level would it make the layout look off?

    I would rather fill it with limestone screening or some sort of gravel because I do not want any weeds growing. I do not want to use sand as I do not want to have an any colony either.

    Are there any other alternatives to fill the flagstone with to prevent weeds.


    • Roger
      10:32 PM, 13 August 2011

      Your flagstone walkway should have a slight pitch to it (away from the house). If you pitch the stones between 1/8 to 1/4″ per foot it should be unnoticeable to people. So if your walkway was 3′ wide and you pitched it 1/8″ per foot, it would be 3/8″ lower on the one side. That’s what I would shoot for in a normal situation. If you feel the situation needs quicker drainage characteristics pitch the walk 1/4″ per foot. So the 3′ wide walk would then be 3/4″ lower on the one side.

      As far as the joints go you could use a small decorative gravel (3/8″ or so). Depending on conditions in your area it could happen that over time the gravel accumulates organic debris and then becomes a medium for weed growth. If the joints between your flagstone are not greater than 4″ you could also use a polymeric product like Gator Dust from Alliance. This addresses your concern about weeds and insects too.

  • Alisha
    9:42 AM, 17 August 2011

    I have an area in the backyard of my rental property that currently has large “egg” gravel in it. The previous tenants dug an area out of the grass, poured in the gravel and installed a firepit. I would like to improve the appearance by laying flagstone over the gravel and spreading grass seed in between.Can I just spread some fill dirt over the existing gravel.

    • Roger
      10:41 AM, 17 August 2011

      To add soil over gravel for lawn there are a couple of things to consider. First, there needs to be enough soil depth to sustain a lawn and its root system. I would say 6″ minimum. Realize that the gravel beneath accelerates the draining of the upper layer of soil, and that could cause the lawn to dry out quicker. If it’s possible, try and remove as much of the gravel as you can.

      Secondly, be conscious of the finish height or grade of the new lawn area you’re creating. Keep referencing that height where you intend to convert to grass so you know how much gravel you need to remove to get that 6″ minimum.

      The issue with setting flagstone over the “egg” gravel is this. I’m going to presume the “egg” gravel is large (perhaps 3/4″ or larger). I would lower the “egg” gravel far enough down so you can replace and add a layer of finer, crushed gravel (1/2 – 3/8″), perhaps 2″ or so thick. This will give you a nice “setting bed” of workable material to set and level your flagstone. The bigger gravel beneath will not be an issue.

  • Holger
    5:08 PM, 28 September 2011

    Hi Roger,

    At the local building supply places, flagstone quantities are typically sold based on coverage per ton such as 100 sf/ton of material. I was told that this is based on pretty tight spacing in the order of 1″ to 2″. Is there a way to convert flagstone quantity calculations from “patio spacing” where flagstone are typically set pretty close together to larger spacing (say 4″ +/-) to allow for ground cover such as sod or thyme to grow inbetween?


    • Roger
      6:13 PM, 28 September 2011

      If you’re figuring approximately 100sf/ton of flagstone, that flagstone should be around 1.5″ thick, which is good for dry-set work. If it were 1″ thick you could get as much as 160sf/ton, but I’d try to use the former.

      To answer your question let me first say that in working with a natural product like flagstone you should appreciate the variability in the material and realize “your sf results may vary”. Having said that, the 100sf estimate for 1.5″ thick stone is allowing for some waste (e.g. cutting, bad pieces).

      I did some quick math in terms of increasing your spacing from approx. 1″ to 4″ and realized an increase in coverage of approximately 20%. Therefore, you could calculate a coverage factor of 120sf/ton with 4″ spacing. Of course if you were doing a large “area,” say a 20 X 20′ area where the majority of the stone pieces were having 4″ spacing all around them, you might get even more coverage/ton.

      Suggestion: Could you start with a conservative estimate and order more if you needed it? Or pick up one ton or 1/2 ton and see what kind of coverage you actually get before ordering the full amount?

      Hope this helps!

  • Holger
    6:27 PM, 28 September 2011

    Thanks Roger, this helps tremendously! Using your suggestion, I need approximately 2 tons +/- and as I plan on picking the stone up myself in several trips with my truck, I’ll probably follow your advice and see how far one or one and a half tons will get me before buying too much.

  • CURT
    12:29 PM, 15 December 2011

    I’m in Houston with an established St. Augustine yard. Can I simply lay the stone on the existing grass?

    • Roger
      1:57 PM, 16 December 2011

      Normally I would not recommend setting flagstone on top of grass. This does not make for a stable base. The organic make-up of the grass and roots is soft and ever-changing as the two decompose.

      As a compromise you could just remove the grass and roots, and set the flagstone on the bare earth. The bare soil would at least give a more stable setting.

  • Chris
    10:26 PM, 12 April 2012


    Great stuff – I have one question.

    I want to make a single file path on an existing lawn but it is up-hill, from the street up to my front area. I would use 2″ thick, at least 18″w large squarish flagstones for good stability as you suggest and would like to have a space of 2′ or more for joints and would like to preserve the grass between stones, doing each stone individually. I would use the small stones underneath.

    1. What do you think is a good joint space both for probability of grass surviving and for appearance for 2″ X 1.5′ flagstones?

    2. Would the slope cause any slippage or problems for the flagstone to settle on the small stones? Angle is not that high, I’d estimate 15 degrees – a vertical rise of maybe 6 feet over 30 feet approximately.

  • Chris
    10:28 PM, 12 April 2012

    Also I wanted to mention I couldn’t “level” per se…. I would have to line them up as best I could so they match the slope of the grade.

    • Roger
      3:01 PM, 13 April 2012

      The flagstone you plan on using sounds good. 2″ is a nice thickness for dry-set work. I’d make sure they’re at least 18″. Maybe you’re thinking of a stone that’s 18 X 24″… is that right?

      In terms of the slope it does sound fairly steep. Normally I’d integrate some steps into a path like that.

      To set them on the slope and with the angle so they’re flush with grade (and the lawn) make sure you use a “crushed fine gravel” to set them in. Avoid a pea gravel that’s rounded because that would increase the chance of the flagstone moving down the slope.

      Keeping the lawn in between the flagstone (as joints) will help secure the stones too. Once the grass fills in right to the stone edge it’s unlikely that stone will move. In terms of spacing and the related joint space, I’d think about the “normal walking stride” a person would have navigating that path. Of course their stride would be different going uphill vs. downhill. Two foot (as you mentioned) seems a little too much. How about 12 or 18″ between flagstones? I would think any joint over 10″ would offer enough support and stability to secure each stone from shifting.

  • Chris
    11:16 PM, 13 April 2012


    Sorry, yes, the flagstones would be about 18″ X 24″ and 2″ thick for stability.

    For joint spacing I meant 2 inches or more, not 2 feet! – what do you think is a good ballpark range for joint spacing for flagstones of that size?

    • Roger
      9:32 AM, 14 April 2012

      OK. I’m concerned about those flagstones moving down that slope.

      It sounds like you want the stones fairly close and that’s fine, but on the slope I might go with a grass joint of 6″. Any closer and I’d be afraid there isn’t enough turf and root mass to secure each flagstone.

      You’ll want the grass you leave as joints to serve as a retaining border. Make sure you recess each flagstone so the existing turf base (soil & root mass) butts up against the side of the 2″ thick stone.

  • Drew
    12:32 PM, 18 April 2012

    Great article! I am getting ready to do a fairly large project (walkway + patio). I do not want grass between the stones. I am going to use stone dust between the joints. My question is, what would be the maximum gap between stones I could have without compromising the stability of the stones? I figure the further apart I can lay them, the more square footage I get out of the stones. I just don’t want to space them out so far that the stone dust becomes ineffective. Any input would be appreciated.

    • Roger
      11:30 PM, 18 April 2012

      First I would ask are you using flagstone that is cut into rectangular and square shapes, or flagstone that is irregular in shape?

      With regard to the stonedust joint it’s actually more of an issue of “look” rather than a concern of stability. Stonedust eventually settles and compacts; it becomes very hard and makes a nice strong joint regardless of spacing.

      So what “looks good” in terms of spacing? It’s somewhat a matter of personal taste, but here’s my view.

      If you’re using pattern stock (i.e. various sized squares and rectangles) I would not have a joint much larger than 1″.

      If you’re using irregular shaped stone (like the stone pictured in the post) I would try not to have a joint larger than 2-3″. If you’re fitting the irregular stones together naturally (i.e. without cutting them) you will naturally have a variation in the joint space. For example, a portion of the joint may come as close as 1/2″ to the neighboring stone and then gradually widen to 2″ at points. That’s perfectly OK and actually adds to the “look and charm” of an irregular flagstone path & patio.

      Don’t worry about the eventual hardness and stability of the stonedust. I say “eventual” because it does take some time for it to settle and bind to itself. Stability is more associated with: using thicker stones (1.5″ is great), using larger stones, and of course setting & leveling them correctly using your base material.

  • Hope
    12:11 PM, 17 May 2012

    Thank you, I am going to build a walkway from our back patio to my fiance’s office.And, the best part… I am a woman…I feel confident after reading this. It matches what I planned in my mind. I am glad to have the details of spacing, measurements and tools to use.
    Thank you and wish me luck!

    • Roger
      9:18 PM, 17 May 2012

      I’m so glad you’re able to move forward confidently with your walkway after reading the article. That tells me it covered the important points.

      Then there’s only one thing left to say…”You go girl!”

      All the best.

  • Elizabeth
    12:19 PM, 4 June 2012

    So glad to see this great post. Thank you for taking time to give so much explanation and such detailed pictures. I am getting ready to lay stones on a long thin grass walkway next to my house. Looking at this, it seems I can place my stones on the grass, mark and then remove the grass from under the stone leaving the established grass in place, since this isn’t just sod that can be “rolled” back. I plan on 4-6″ between stones since I like that look with lots of grass. After I fill the stone-shaped areas with 3-4″ of 1/4″ gravel, do I need to, or should I, also put down some sand? Do I need to tamp the stones down with something more than just my feet?

    Thanks for your help! –Elizabeth

    PS I realize the grass in-between the stones will get damaged to some extent during the process and I am ready to level with additional dirt and reseed. I just want to save myself the hassle of removing all the grass. I’m just trying to think through all the step out loud here.

    • Roger
      8:34 PM, 5 June 2012

      Basically you’re planning on doing all the right things.

      The 4-6″ of spacing between flagstones is great. I wouldn’t use sand if you’re using 1/4″ gravel or smaller for your setting base. The gravel will work fine for setting the flagstone.

      In terms of tamping, if you have a hand tamper that will work great for this sort of project. But I think you’ll get by with just packing the ground and gravel base with your feet. For the flagstone themselves, your feet and weight (I’m not implying anything here 🙂 ) will also be adequate.

  • jim
    9:09 AM, 17 June 2012

    I am building a narrow stone walk using 3 inch flagstones on a downhill pitch. I would like to have grass in between stones. Must I install a base, or can I just embed stones into dirt to ground level and then plant grass or place sod in between? Most stones are quite large and heavy.

    • Roger
      10:24 AM, 17 June 2012

      One concern I have when setting flagstones is the build-up of moisture underneath the stone, but in your situation you’re on a slope so it’s less of a concern.

      For me I would still dig down an inch or two deeper than the thickness of the stone and use a small sized crushed stone or very coarse sand (or grit) as a “setting base”. Yes it will help prevent moisture build-up under the stone, but also it just makes it so much easier to set each flagstone and get them sitting nice and stable.

  • jim
    10:31 AM, 17 June 2012

    OK, great. Thanks so much for the advice. — jim

  • Vicky
    3:04 PM, 20 June 2012

    I am going to do a simple labyrinth in the lawn out of 5 1/2 square pavers. I want to set them flush to the grass so we can mow over them. There will be about 2 inches of grass inbetween each square. Is there a good tool to cut out the sod? Do you think I need to put crushed stone beneath each square even though they are small?



    • Roger
      6:18 PM, 21 June 2012

      Hi Vicky,
      I’m thinking it would be most efficient to remove the grass throughout the area the pattern will be. That includes the planned 2″ joint of grass you want when the project is complete. Then, you’ll set the stones as you wish the pattern to be and simply replace that 2″ joint piece w/ sod (or soil and seed) after the stones are set.

      I don’t know how many stones you’re planning on setting in your pattern, but it would take a lot of time and hard work to remove the existing grass and leave that 2″ joint of grass in between each.

      To cut the outline through the turf that you’re planning to remove I’d use a garden spade. If the area is relatively small that the stones are covering, you can use the spade to also slide under the turf and remove it like sod. If the area is quite large to remove, we then use a grape hoe to chop out the existing turf after we cut the outline with the spade.

      I do think it’s a good idea to dig down an inch or two more than you need, and lay down some fine gravel or coarse sand to set each stone. I think you’ll really appreciate how much nicer (and easier) it is to set and level each stone with a little setting bed material.

  • Sammy
    1:48 AM, 4 July 2012

    Thanks for the info in this article. My project area is quite large (40 X 15) so I was thinking of mowing the grass as low as I can, put coarse sand under the stones and let the grass grow back and fill the gaps. Do you foresee significant issues with this approach?

    Thanks a lot for your time & effort.


    • Roger
      5:53 PM, 4 July 2012

      The problem with this approach is you’re leaving the grass (even cut short) and its root system underneath your flagstone. Yes the coarse sand and flagstone will kill the grass beneath, but you’ll have this unstable layer of organics (i.e. decomposing grass, roots and other organic matter).

      Also, you’re not recessing the stones within the existing grade/soil, so the stone is floating on top and free to wander.

      Perhaps another approach would be to strip the grass and its roots of the area. Set the flagstone with a little coarse sand to help with the leveling & stabilizing, and then place top soil between the set stones and seed.

  • J J
    11:07 AM, 12 July 2012

    I live in North Dakota with freezing and hot temps. I am planning a flagstone patio with the layers of crushed rock and sand. I am also doing a walkway from the patio to my garage do you think I also need the under layers for this or would right on the soil work? Is it a good idea to do the layers for the patio? Thanks.

    • Roger
      3:20 PM, 12 July 2012

      In your location I would prepare the base thoroughly. That would include a gravel base of 4″. Also, I would not use sand to set the flagstones. We have found that sand (even coarse mason sand) can hold enough moisture that it reacts with the “freeze/thaw cycle” and can heave your flagstones. We use a 1″ or so layer (setting-bed) of small crushed stone such as 1/4″. Our base below that is usually 3/4″ crushed stone.

      It’s also advisable to compact the sub-base of earth before you add the gravel layer(s) for your patio. You want to minimize any settling of your flagstone over time.

  • genie
    6:57 PM, 12 July 2012

    What a great article–thank you, Roger!
    We’d like to turn our concrete patio (14’x14′) into flagstone with turf. Our friend suggested we layer with cement (vs crushed gravel) underneath each stone but I’m concerned aobut drainage. What do you think of this “wet” approach?
    Thanks, again!

    • Roger
      3:34 PM, 14 July 2012

      Your concern for drainage is valid. Grass will need both drainage and sufficient soil depth to establish and grow.

      We have installed pavers and flagstone over existing concrete slabs, but not with grass joints.

      If your heart is set on flagstone w/ grass joints you should demo and remove the existing concrete.

  • Luke
    10:33 AM, 14 July 2012

    I’m just about finished my flagstone walkway and i’m not sure what I should fill the cracks with? I know you have talked about decorative stone in between. What else is good to use in between say 1 to 2 inch apart cracks?


    • Roger
      1:34 PM, 14 July 2012

      If you’re located in an area w/ freezing temperatures you’ll need to be conscious of “heaving”. This is where moisture below your flagstone may collect and then cause the flagstone to heave (move) when it freezes. This, as you’d expect, affects what you’ve used in the joints.

      If you have freezing temps. and you’ve set the flagstone on a well-built, well-drained base of crushed stone (4″+ deep) including a finer crushed stone (e.g. 1/4″) as your setting bed, the flagstone should stay stable year round. In this case you could use a polymeric joint filler product like Gator Dust.

      If, on the other hand, you’re concerned about the flagstone heaving in the winter, you’ll want to use a non-polymeric material like plain coarse mason sand or plain stone dust.

      If you use a polymeric based product that binds and hardens on a flagstone surface that heaves, the joints can become dislodged. It’s then unlikely they can be returned to their original position within the joint. A plain coarse sand or stone dust can easily be re-swept and placed back into position when the flagstones settle back after heaving.

  • genie
    2:33 PM, 17 July 2012


  • Luke
    8:55 AM, 20 July 2012

    Hi Roger,

    Would envirostone work between my flagstone joints? You did mention Gator dust but it isn’t at hand for me. The envirostone for flagstone wont harden like mortor but is more courser binder.


    • Roger
      10:17 AM, 20 July 2012

      I just checked out Envirostone on their website and it seems like it should work fine. Thanks for bringing this product to my attention.

  • Luke
    9:38 AM, 20 July 2012

    Im just wondering about the depth of my flagstone spaces because Ive wedged the crushed limestone under the flagstone and the edges so they stand firm. When I put the final product to seal the cracks Im hoping that there will be a ok depth of 1 to 2 inches. Most of my flagstne path you can see the crush limestone in between. I’ll probably have to take some out in order to apply the final product.


    • Roger
      10:23 AM, 20 July 2012

      The remaining depth you have for your joint material (of 1″ or >) should be fine. There’s no need to make it any deeper, and by doing so you could undermine the stability of the flagstone.

  • brian
    11:54 AM, 21 July 2012


    Thanks for the article. I’m in san antonio with warm temps most tine. Is there or what is the problem with setting flagstone directly on grass with no base. I have bermuda greass very thick. I think it will settle ok. Whats your opinion.

    • Roger
      1:07 PM, 21 July 2012

      My main concerns would be: 1) the flagstones right away would be unstable sitting on grass, and even over time the decomposing grass and roots would present an unstable, organic base. 2) With the flagstones sitting “on top” they would be a tripping hazard and the lawn mower would be bumping into their edges and sides.

      By digging down and removing the grass and roots you solve both concerns. And even though you don’t have to worry about freeze-thaw and heaving, I’d still dig deep enough to lay down 1″ of setting-base (e.g. coarse sand, fine gravel, etc.) to set the flagstone on. It will make it so much easier for you to level and get the stones nice and stable.

  • Luke
    6:31 PM, 27 July 2012

    Hi Roger,

    I choose to go with the Gator Dust for my flagstone joints. My question is: For the winter for snow removal and ice, will salt deteriorate the joint filler or flagstone when applied to melt snow?

    Regards, Luke

    • Roger
      8:38 PM, 30 July 2012

      Hi Luke,
      Sorry for the delay in answering this question, but I’m still waiting to hear back from a couple of suppliers as to whether salt will affect a polymeric sand product.

      Actually, the landscape contractors in my area use ice melt products w/ calcium magnesium in them. It’s way more forgiving to paved surfaces and the adjacent landscapes. (However, it is more expensive than salt.)

  • Luke
    7:06 PM, 30 July 2012

    Hi roger:

    Im just about done my flagstone front walkway/small parking spot. What I did not mention to you was that I wanted to use it to park a smaller car on. Now i’m not sure what joint filler I should use for my flagstone spaces? I want something that will seal the joints to keep it smooth to the surface with no cracking. I’ve done a fair bit of research on all the different products out there. My concern now is I like what Gator Dust can do but they say its not used for driveways. Gator Dust has a ten year warrenty over all the other products and there are dozens of good reviews on it. Where I live in Canada, Gator Dust is called Permacom, and i’m still trying to find a supplier near me to get it. I will be taking back the joint filler I got at Home Depot : Poly Dust Bond.

  • Luke
    10:44 PM, 30 July 2012


    Thanks for these resourses!
    The only problem is my flagstone joints are larger than 1.5 inches all around. Would these products work with larger joints?


    • Roger
      10:09 AM, 31 July 2012

      If you call Alliance and describe your situation I’m sure they’ll be able to guide you on their product line.

      At the end of the day it might be best to fill the joints with a small “crushed” stone (3/16 – 1/4″). Considering the climate and use (parking car), the crushed stone will drain well (presuming the base was done correctly) and move with the dynamics of the surface.

  • Luke
    11:01 PM, 31 July 2012

    Thank yor Roger so much for all the help.

    I have purchased some gator dust ( in Canada its called permacon ).
    So i will be gettting ready to sweep it into the cracks. It has been a excellent project and looks fantastic!
    My last question is this: What happens if it rains in between the 24 hour curing process after ive completed the installation of the Gator Dust? Will it be ok? There lots of rain headed our way this coming week and I have no choice but to sweep it in tomorrow evening. The next day is supposed to be sunny all day than the rain will start up again. I’ve tarped my walkway the whole day today because of the rain. Before I sweep the Gator Dust in the joints they need to be absolutely dry right?

    Thankyou once again for your assistance,

    • Roger
      8:02 AM, 1 August 2012

      Hi Luke,
      It sounds like your project is turning out great!

      I’m a little concerned about using the polymer sand with flagstone on an area you may park a car. I think you had mentioned that was a possibility. Any movement in the flagstone (like from the weight of the car) will cause the hardened polymer joint to crack and possibly become dislodged.

      In terms of the 24 hour curing period, you don’t want to chance getting rain on it. Can you simply tarp over the area?

  • Luke
    9:17 PM, 1 August 2012

    Hi Roger,

    My project is finished and looks geat! The Gator Dust seems to be setting perfectly. There is though a slight chance of 1 mm of rain in the forecast for tomorrow. That little bit of rain shouldnt harm the curing process should it? The watering process of the Gator Dust was done around 6:30pm and the 1mm of rain is forcasted for possibly 12pm tomorrow. So it will be rainless for 18 hours.
    As for the parking on it, that is out of the question for us now. This flagstone path will only be used for walking on.

    Thanks Roger

    • Roger
      11:20 PM, 1 August 2012

      With that little rain, and after 18 hrs., you should be OK.

      Feel free to email a picture of the finished project. I’d love to see it.

  • Luke
    9:11 PM, 2 August 2012

    Hi Roger,

    Now that the Gator Dust has cured a good 27 hours + could I wash down the flagstone? I was wondering if down the road, say some of the Gator Dust needs some topping up…. Could I spread more of Gator Dust over the areas to repair it? Is it normal for the product to have some spots where when you press it its somewhat soft. For the most part the joints are sealed rock hard. It’s quite a impressive product!!


  • Grace
    5:44 PM, 11 September 2012

    I have a very nice stone walkway in my yard. The soil between the stones has eroded over time and I find the need to fill the space and my preference is grass. The stones are about an inch apart and I’m not sure the best way to go about building up the soil and ultimately spreading grass seeds (i.e. a mix of soil and seed?). I tried that fluff stuff with the seeds in it but that didn’t work; probably because there wasn’t enough soil in there. Could you offer any suggestions?

    I know at one time there was beautiful grass growing between the stones so I don’t think its impossible!

    • Roger
      11:37 PM, 11 September 2012

      Hi Grace,
      One inch of joint space is not a lot for grass to thrive, but I’d give it a go since you’ve had grass there before.

      Is it reasonable to suggest removing the existing soil between the joints? I guess it depends on how many joints there are. I have a narrow mason’s tool for jointing – it’s about 1/2 -5/8″ wide, and that would work well to clean out the joints of existing soil. Just dig and flip the old soil onto the flagstones (with the narrow tool) and then sweep it up later. If you could remove about an inch deep and then loosen the base while you’re at it, that would be good.

      Then, if you can get some good quality top soil and fill in the joints to just below flagstone height (1/4″ below or so). I would then add the appropriate grass seed (sun or shade mix/blend) on that soil level. I’d finish it off by adding a bit more top soil on top and just press it firmly with your hands. (In a large lawn area we’d use a roller for this step.)

      The trick now is to water/mist it gently and keep the soil slightly moist for germination. BTW, this is a perfect time of year for this.

  • Steve
    10:03 PM, 2 December 2012

    Hi Roger, your posts have inspired some good ideas. I have a combination of a few of the previous posts, but not sure of the best solution overall. We have 2 small lawns joined by an informal flagstone walkway. The flagstone is simply imbedded into decomposed granite. This walkway has been adequate for the 15 years since I built the house and landscaped the backyard. We now have 2 large labs that kick up a bit of dust so I find myself sweeping the walkway often and never find it looking very tidy. I was thinking of refinishing this walkway with gator dust or some other polymeric sand product and have a couple questions:
    1. Should I contain the walkway with a rigid border of some sort? I want to keep the informal feel, but don’t walk the walkway breaking down either.
    2. In a couple spots of the existing lawns, the lawn remains tracked and muddy in part due to the dogs, but also due to downslope/drainage, etc. Is it crazy to install a couple slabs of flagstone randomly in the lawn area? these locations tend to be adjacent to the walkway in question, so by removing some of the lawn border, I may be able to blend nicely.
    Thanks for your thoughts. Steve

    • Roger
      9:11 AM, 5 December 2012

      I’d like to help, but I’m having trouble visualizing the situation.

      Could you email me a picture or two?

      • Roger
        1:04 PM, 6 December 2012

        I got your email with the 2 pictures.

        In your email you mentioned you intend to make the entire area where the flagstone path is currently *all* flagstone. I agree. Try to make the joints reasonably small and then use a polymeric joint sand like Gator Dust.

        Also, where the flagstone meets planting areas you could use a border paver edging, but realize that you’ll need to cut the flagstone along that edge to meet the plastic edging. Alternatively, just use larger pieces of flagstone along the outside and they should, for the most part, stay in place because of their size and weight. Then you don’t have to cut the edge or use plastic edging; it will look more natural.

        With regard to the “muddy” area by the walk and garage door you mentioned a drain you had installed. Where does the drain exit?…to a dry-well or an open space somewhere? Make sure the drain is working correctly. I can’t tell by the picture how you have the drain designed and built, but here are some pictures of a “stone intercept drain” we built along a walkway.

        This area is low because the lawn had to be graded this way to keep the surface water moving. The lawn in this spot would stay excessively wet, and the walkway would become dirty and discolored because of the constant flow of surface water over it.

        In this first picture you’ll see we excavated the area, pitched the base of the excavation toward where the plastic catch basin was installed, and even drilled 1/2″ holes in the sides of the plastic drain basin to give more spots for water to enter into the basin.

        The excavation was lined with filter fabric and then coarse gravel was added to fill around and up to the top of the basin. The top of the basin was deliberately set 3 – 4″ below the projected finish grade so we could add decorative stone work on top to disguise the drain work below.

        Now, all of the water runoff has no choice but to enter into this stone intercept system. BTW, it is piped underground to exit into a nearby dry-well on the property.

        The homeowner was very pleased because the drainage solution actually turned out to be an interesting feature in the landscape.

        I hope this helps.

  • Steve
    2:37 PM, 6 December 2012

    Roger, thank you so much for both suggestions:
    1. I will decide on whether to use a border once the stone is bought and laid out.
    2. The stone interceptor drain is exactly what I need and will work here. Thanks so much.

    Okay, so now you’ve got me rejuvenated for my yard. All around the lawn border, the grass elevation has risen thru the years to where it is now above the patio or adjacent mow strip. Is this normal with time, and is there a clever way to lower it. The lawn is in good shape, but is small so I am not apposed to removing and reinstalling if need be.

    Thanks again for all your help Roger.

    • Roger
      1:42 PM, 10 December 2012

      Hi Steve,
      I have come across lawn areas that have gradually risen over time. And there could be a number of reasons for this happening. Often the spot that has gotten higher is on the receiving end of a run-off situation. The run-off carries small particles of organic matter (and the like) that collect in this particular lawn area.

      In any case we usually remove the lawn, regrade and either re-seed or sod. If the existing lawn is in good shape you could carefully lift the sod, regrade, and then replace the sod that you lifted.

  • Pamela Walker
    2:51 PM, 11 December 2012

    Roger, THANK YOU so much for this wonderful trunk full of useful info! For 7 years I have lived in a Co-Housing Community in Davis, CA. When I moved here there were flagstone paths between back yards, but they weren’t wide enough for my wheelchair and they had unsettled and weeded over through time. I formed a Path Committee and we have slowly redone different areas each year. (You can see our paths on our website photo: I’ve been learning the ropes through doing, but your notes have helped so much! For example, I’ve been using a mix of a gravel layer AND a sand layer. It seems to me now that I should NOT use sand and use a bit more gravel. Yes?

    This year I am tackling a bigger project than paths. The back patio of our Community House has some drainage problems and the adjacent entrance has tripping hazards. I am planning to redo the whole area (currently it is a mix of concrete, uneven flagstone, sunken bricks and cracking pavers) in flagstone. Quite a project, but I visualize a great result, especially if I can get the community to agree to buy EnviroStone to joint the stones.

    Two questions I have for you now, but you are likely to hear from me again if you don’t mind: (1) Do you recommend 4 1/4 in. gravel for our area and how much settling can I expect? (I will be trying to match the flagstone level with the concrete entrance pad level for wheelchair access.) (2) Is there a time of year that flagstone goes on sale or is cheaper to buy?

    • Roger
      9:52 AM, 13 December 2012

      It looks like a nice community you’re in.

      With regard to your questions, you mentioned using 4 1/4 in. gravel. Perhaps that’s a typo, but your base for the patio should be made up of 3/4″ (+ or -) gravel. Settling can be minimized (or eliminated) by compacting the sub-base earth before you install the 3/4″ gravel. Try to use a power plate compactor rather than compacting with hand tools. You can rent one. If we’re unsure of the sub-base (earth) make-up or stability, we’ll lay down filter or landscape fabric after we compact. Then we put the 3/4″ gravel on top of the fabric.

      For the top layer setting-material we prefer to use a coarser material than sand for setting flagstone. A 1/8 to 1/4″ crushed stone works great. For us here in the northeast it maintains a porous base underneath the flagstone so we minimize (or eliminate) “heaving” from freeze/thaw cycles.

      You mentioned a drainage problem and it’s hard for me to comment on that w/o knowing the details. I will say this though: make sure all your work is pitched “where you want the water to go”. And this includes the sub-base. As the water migrates down through the base material you want the sub-base pitched to encourage the water to move in the right direction.

      Re flagstone costs: In our area the flagstone cost remains consistent regardless of the time of year. The best thing to do is shop around. A vendor may have too much of one type of flagstone and want to discount it.

  • Leah
    12:44 PM, 23 March 2013

    Hi Roger –

    Thanks so much for this great post on how to lay flagstone in lawn, and particularly for all your follow-up answers to peoples’ questions in the comments. Our lawn frequently get soppy in Winter – I live in Victoria BC – and a flagstone path cutting across to the driveway will be good to have. With all your helpful tips I feel like I can go ahead and do this job, and do it well!

    All the best and thanks again –

    • Roger
      5:24 PM, 23 March 2013

      Hi Leah,
      Thanks for leaving your comments and kind words.

      In your situation in particular, the gravel base is so important. This is what will keep your flagstones stable in those wet conditions and reduce any “heaving” you might get with the freeze/thaw cycles.
      All the best.

  • Steven
    12:09 PM, 15 May 2013


    Thank you for the article. I went through most of the comments and have a question. I am extending my current patio and I want to use flagstone with 4-6″ of grass (already well established) between each stone. The seller of the flagstone said that I would need a layer of concrete as the base if I purchased 1″-1.5″ flagstone. If I purchased 2″-2.5″ flagstone, I dont need to put concrete below the stone. Based on what you said…

    “I wouldn’t use sand if you’re using 1/4″ gravel or smaller for your setting base. The gravel will work fine for setting the flagstone.”

    …I am leaning in the direction of the 1″-1.5″ flagstone on a 3-4″ base of 1/4″ gravel. Is this correct?

    Thank you in advance for you time and answer.

    • Roger
      3:33 PM, 19 May 2013

      The thicker the better for dry-set flagstone work. The reason is stability – the bigger and heavier the piece of stone, the more stable it will be.

      Having said that, it would be OK to use the 1 – 1.5″ flagstone (set on 1/4″ gravel), but do your best to use large pieces. I would say nothing smaller than 18 X 24″. If you set them nice and solid on that 4″ base and then have 4-6″ of soil and grass between them, you should be fine. The lateral support that the earth and grass give will help secure them. Try to make sure when you’re setting each stone that there’s no wobble to the stone…no matter where you step on it.

  • Beverly Hull
    2:27 PM, 3 June 2013

    I have a Bermuda lawn that probably has very deep roots. Would you recommend some type of material, cloth, plastic or……to keep the
    Bermuda at bay? Thank you for your assistance. Bev

    • Roger
      11:18 PM, 5 September 2013

      Hi Bev,
      I don’t have any experience with Bermuda grass as it’s grown in the southern part of the US.

      I would think a barrier of some kind that’s strong & solid and goes down into the earth several inches would control its spreading. Masonry, stone, heavy plastic, etc. These are the same methods we use (to one degree or another) to control any number of spreading/invasive plants.

  • ceasar
    10:11 PM, 11 July 2013

    Thank you for this great advise. I have one question my customer ask me to expand her drive way with flag stone for a extra car( her son is starting to drive). I really need to know if this is OK to do. Am worried about weight, possible cracking?? And she wanted grass joints. Is this OK to do?? Extra precaution to make sure job lasts. Please help. These is my first flagstone job am comfortable your advise was great just wanted to make sure if needed I do the extra steps. Thank you

    • Roger
      9:36 PM, 14 July 2013

      Hi Ceasar,
      Thanks for your question. I’m so glad you’re researching how to do this work for your customer correctly. They’re lucky to have you doing the work.

      I contacted my friend and colleague Dave Kennedy, who is one of the contributors here on LandscapeAdvisor.

      Dave sent over a picture of a flagstone driveway landing he did back in 2000. He said the flagstone he used was bluestone and it averaged between 3 and 4″ thick. It was dry laid on a 1 ½” stone base with 3/8” bedding stone. The flagstone is driven on everyday and no stone has cracked in 13 years.

      Hope this helps.

  • Cherylynn OMelia
    8:04 PM, 19 July 2013

    I bought a fifties cottage and would like to do a flagstone path and patio in the grass/backyard. I have not done this type of work before. I am somewhat strong; however, I am female. Will this be an overwhelming job for me?

    • Roger
      12:46 PM, 21 July 2013

      There are a couple of stages of flagstone setting that can be physically demanding.

      Excavating the area to the proper depth can be difficult depending on the size of the area and the hardness of the ground. You certainly can and should consider renting a mini-excavator for the task if it’s too big a job.

      After excavation you’ll need to bring in the “base stone/gravel”. You can have that delivered and then move it to the patio/walkway area with a wheelbarrow.

      The flagstone can also be delivered and you can move the pieces with the wheelbarrow too. For dry-laid flagstone work I always recommend bigger and thicker pieces for stability. This is where it may become difficult for you. Perhaps at some of the more physically demanding phases you could get some help. For example, having two people to maneuver the flagstone pieces and help set them would be great.

      If you approach it casually and take care to not push yourself beyond your physical capability, you could make it a nice DIY project. Please be careful. I have back issues from years of landscape construction work and I would not want you to have anything similar.

  • Joey Zamora
    11:50 PM, 22 September 2013

    My parents just moved into a new home in Houston where the sod was just laid a few days ago and there is a good layer sand laid underneath the sod. I’m wanting to lay a flagstone walkway on the side on the house leading to the poolhouse. My question is can I get away with using the sand that is under the sod instead of using gravel to stabilize the flagstone. I will be using large pieces of flagstone with 6″-8″ spacing between the stone


    • Roger
      8:17 AM, 23 September 2013

      You should be OK. I’m curious why there’s a layer of sand underneath the sod. Is the soil naturally sandy or did the installers add the sand?

      Since the sandy ground should drain well and Houston is in a warmer climate zone, the flagstone should set just fine. Plus you’ll be using large pieces…great!

  • Liz
    12:40 PM, 5 November 2013

    We are considering stone pavers of some type through a lawn area. Will extra work need to be done between the pavers or can we just mow over the walk as a whole? Thank you for your input.

    • Roger
      11:17 PM, 5 November 2013

      Hi Liz,
      I’m not sure I understand what you’re planning to do.
      Most manufactured pavers are set so that they touch and form a continuous surface. With that you’ll not have any grass growing between the paver units.
      Now there are some manufactured “pavers” that mimic flagstone, both irregular shape and dimensional pattern, e.g. 12 X 18″, etc. Something like these you could set as we did on this project and have grass growing between them. And just like on this project, you’d run the lawn mower right over them.
      I’ve found that over time the grass does begin to grow over the edge of the stone. Perhaps once a year you should take a knife or some other edging tool and cut back the encroaching grass to the original edge.

      Here’s an example of such “pavers” from Techo-Bloc.

  • Allie
    3:43 AM, 18 February 2014

    Hi Roger,

    This is a really great article showcasing some really beautifully done work.

    I’m about to install a flagstone path across what will be a large lawn area. The soil on the property is very sandy & compacts very tightly. I’m wondering if we could forgo the crushed gravel if the soil base is thoroughly prepared & compacted, and the flags are wiggled into place to insure good contact. The flagstone will be a very durable 2-3″ thick with 12-18″ spacing of lawn in between pieces.

    I’d really appreciate your thoughts!


  • Allie
    3:45 AM, 18 February 2014

    I forgot to specify—this site is in coastal CA where we never get hard freezes, and the soil is extremely well-draining.

    Thanks again 🙂


    • Roger
      9:40 AM, 18 February 2014

      Hi Allie,
      Considering the flagstone you’ll use is 2-3″ thick, existing soil is sandy and well-drained, and your temperatures are moderate, I think you’ll be fine working with your ground as the base.

      Plus, the fact that the existing soil is sandy will make it relatively easy to adjust when leveling and stabilizing each flagstone.

      You might consider keeping a small amount of the excess sandy soil just in case there’s some settling.

  • DJ
    3:50 PM, 5 March 2014

    We live in San Antonio Tx on 2 acres. We are building a pool with a flagstone patio. We don’t want to mow or water grass. We were going to just lay down extra flagstone to take up some of the land but now our pool builder is talking to us about synthetic grass. Can flagstone be laid on top of synthetic grass? Nothing but dirt right now. So anything would be an improvement. Thanks for the help.

    • Roger
      10:23 PM, 5 March 2014

      DJ, I’m not completely clear on your situation, but here are some of my thoughts.

      A common look for an inground swimming pool is to have a patio/walkway around it. And this can be made from a number of materials, such as the flagstone you were planning. Typically flagstone is either “dry-set” on a prepared base or “wet-laid” on a concrete base. You could create a look that combines grass with the flagstone like is shown in this post. I’ve done this before, but used “patterned” flagstone, i.e. squares & rectangles. It’s not the most practical thing because cutting & maintaining the grass in-between the stones is a challenge and invariably causes grass clippings in the pool.

      The idea of using artificial turf would solve the problem of cutting & lawn maintenance. And the base preparation you would do for the flagstone should be similar to how you’d prepare for artificial turf. If you used artificial turf in-between the flagstone, I’m not sure how that would work. Specifically, how do you securely install smaller strips of artificial turf so they don’t move?..although I’m sure there’s a method. Is that the look you’re going for?

      Otherwise, you could do a flagstone patio/walkway without turf in-between, and then cover other open areas with the artificial turf.

      You could also use all artificial turf – right up to the pool coping.

      Again, it’s hard to give advice on matters like this when I’m not actually there to see and discuss with you. Don’t hesitate to comment again if you have further thoughts or questions.

  • May McIntosh
    12:56 AM, 7 April 2014

    Hi there!
    I live in Coquitlam BC. Our soil is very thin 1″ and we have clay,silt and rocks underneath. We never had drainage problems as we are on a hill, on the high side. We had a large plastic sandbox for 5 years and removed it last week. The ground under it is now compact soil (mind you loaded with earthworms!). I didn’t lay 4″ of sand under each flagstone, only 1″. Now I have standing water against the last row of stone against a retaining wall. I think because I lifted the sandbox, I’ve exposed a compact ground that isn’t used to draining yet. I used a pitchfork to aerate around the stones. Should I dig a drainage trench and dry well or wait for the ground to revive after a couple weeks? My final plan is to grow mossy ground cover between the stones.

    • Roger
      11:27 PM, 13 April 2014

      Without seeing the situation it’s hard to give precise advice, but it’s important the area you’re working on has pitch (amount of slope). In other words, there should be approximately 1/4″ of pitch per 1′ of run. So if the area is 6′, you should have 1.5″ of pitch, which will ensure that water moves out of the area and continues on its way.

      It’s likely the compacted ground is not helping, but proper pitch is the most important factor.

  • Roman
    11:32 PM, 7 April 2014

    Hi Roger. Thank you for providing us with your article. I am in the process of installing flagstone slabs. I want to have these set in with the grass growing in between the gabs. These slabs are 2″to 3″ thick. The first challenge was moving them from my driveway back into my backyard, they weigh in range of 200 to 300 pounds. I lay them down in the best possible pattern. They sat for a week. I just scraped the grass from under each one of them and added decomposed granite, in some spots where needed to keep them from wobbling. A couple of them broke because they were thinner on some corners as a stepped on them to verify that they were stable. I thought the weight on these slabs would be enough to keep them in place. The turf they sit on is fairly leveled with a small slope to where water will run off. I am not at ease, thinking that some day they will break. I know about the gravel and sand base technique. However, I wanted to know if they stones would be ok with just a sand base. I know the hard work involved in digging and filling for each stone. I need some advice on the least expensive and more reliable method of material to use under those stones. Or should I leave them as they are with soil and some decomposed granite I use? My next step was to let them sit for a while and settle. Then I was going to force sand through the sides with water pressure, to keep them from breaking in the future.
    Thank you, Roman

    • Roger
      11:39 PM, 13 April 2014

      There’s no question the stones will be better off when set in a well-drained, stable base. A coarse, masonry sand would be a good choice, but we really like to use crushed stone in a very small size.

      Could you get someone to help lift the stone vertical so its on edge? Then, as the one person holds the stone vertical, you could dig out the existing soil, turf, etc. and fill will coarse sand or smaller gravel. Lay the stone down together and check that it’s set right. You can either lift again to adjust, or tweak as it sits by packing from the sides.

      It’s great that you have pitch (slope) so that the water drains properly. I’m sure you’ll continue to maintain that if continue to work on the stones.

  • Brendan
    3:08 PM, 23 May 2014

    Hello Roger. I am in the process of expanding my patio into my garden. Basically what I did was reclaimed a section of my stone driveway and and a section of my garden. I want to use the irregular flagstone spaced 5-7 inches apart and grow a Blue Star Creeper ground cover as well as strategically placed plants to make patio/garden area so the garden feels less separated from the sitting and entertaining area. I decided to use fill dirt and top soil to level the area that was once the driveway rather than just pour and tamp a paver base so the plants will have sufficient soil to root and thrive. I found your article to be the most compatible with my design idea because it only calls for the paver base to be put beneath each individual stone. I called the stone yard to order my paver base and he sent over what he called “quarry dust.” It doesn’t seem as though this quarry dust packs down as tightly as the paver base I’ve used before but it does seem to allow me to forgo using the paver base and then using sand in order to level the stones. My question is will this “quarry dust” be enough to keep the stones from settling and sinking into the ground. I am concerned since the fill dirt is about a 1 foot deep and was just recently put in. I did use a lawn roller to compact the fill dirt so I don’t expect too much settling but would like to protect myself from having to pull these stones up again in a couple of years.

    • Roger
      8:37 PM, 4 July 2014

      Your design idea sounds great. The wider spaced flagstone with low plants between them is a great look and will make for a nice transition to the nearby patio.

      I’m not too concerned Where you’re setting flagstone in the previous stone driveway area. That ground is presumably well compacted.

      It’s the section of existing garden where settling could be an issue with the flagstone.

      Quarry dust should eventually bind and get quite hard. The roller will help with compaction. Whenever you’re compacting materials you should do it in “lifts”. That means to first compact the base of your excavated area, then add 4″ or so of new material (e.g. quarry process) and compact that. Then add another 4″ or so and compact that – and so on until you reach the desired height of compacted base material. The one inch setting layer of sand (or quarry dust) you use last for leveling the flagstone becomes compacted as you set and tamp each stone.

  • Scott
    10:49 PM, 9 June 2014

    Great walk thru! Thank you!

    I am starting from scratch – no lawn in place, no flagstones. Tillered and prepped the area
    (pretty small – 14×14) for planting sod. I see one of two approaches:

    1) Lay down the sod, give it a couple three months to take root, and then remove the sod where I want the stones to go (essentially as you have described). Downside here of course is the extra time and wasted expense on sod that gets cut out.

    2) Lay the flagstone wide enough – 3 to 5 inches or more – and then work the sod into the cracks. My concern here is that the more narrow and irregular pattern to the new sod won’t take root. Is this concern valid?

    I prefer the second approach for sake of time and money, but don’t want that sod to go dead or shallow.

    Thanks much!

    • Roger
      11:49 AM, 20 July 2014

      I like the way you’ve thought this through and your 2 “approaches”. And, as you’ve mentioned, there are pros & cons to each.

      I’d also go with the second approach. Try to keep the space for the grass joints wider – leaning more towards 5″. And after the flagstones are set (with gravel/aggregate), go through each joint and just clean them up of any excess gravel and replace (where necessary) with top soil. You could even add a soil additive like Soil Moist to this joint soil to help keep it from drying out prematurely and until its roots take hold.

  • Rita
    1:20 PM, 20 June 2014

    Could I simply place the stones on the existing grass which would kill the grass after a bit of time? Wouldn’t the stones “settle” into the lawn allowing me to mow over them?

    • Roger
      12:17 PM, 20 July 2014

      I’m afraid that just setting the stones on your existing lawn would not work too well. At the very least I would set the stone, trace around it, and remove the grass and enough soil to recess the stone flush with the surrounding grade.

  • Jon
    12:41 PM, 3 July 2014

    does a walkway made out of irregular flagstone has to be complete flat? i have seen some work where it the walkway made out of irregular flagstone is not completely flat that they are some stones higher than other.. is the right?

    • Roger
      1:49 PM, 13 July 2014

      Unless you’re trying to achieve some type of irregular look, I would make all your flagstone edges as even as possible to one another. Pitch is another topic entirely, and I have an article here on that.

      When walking surfaces have uneven edges it becomes a real safety hazard, not to mention a nightmare to shovel snow.

  • Beth Ann
    5:19 PM, 26 July 2014

    This is all helpful information. One question – I have St Augustine grass and I am wondering how well it will work in between the stones. Do you think that it will be a lot of extra work to as the “runner” of grass with start growing onto the rocks?

    • Roger
      1:41 PM, 6 October 2014

      Beth Ann,
      I don’t have any experience with St. Augustine grass, but most grasses (even in our northeast location) just by their nature spread – some more aggressively than others.

      In our area I find that if the grass is cut back to the flagstone’s edge once/year, the look and function is maintained. I use a heavy duty knife with a 4″ blade. It’s the same one I use when laying sod and cutting/fitting the sod around objects.

      Just find the edge of the stone under the over-growing grass and stick the knife in right against the stone. Simply trace the outline of the flagstone while cutting with the knife. I keep my sharpening stone nearby to freshen-up the knife’s edge every now and then.

  • Paul
    9:39 PM, 11 September 2014

    You may have gone thru this but I am wanting to do a dry lay walkway leading up to a pool. My only issue is is is a dry area 90 percent of the time and during the summer here in lousiana, but when the sun shifts and we get the wet weather, this area could become a little wet. I was planning on cutting out the grass and digging the flagstone into the ground, but what should I do with a wet area? Thx!

    • Roger
      10:54 AM, 30 November 2014

      I would excavate the path area (length & width) to 6″ deep so you can install a base layer of 3/4″ crushed stone/gravel. If your soil is generally clay-like and does not drain well, then I would also install a run of 3″ diameter perforated drain pipe that ideally can be run (with pitch) and tied-into a nearby drainage system. Or perhaps there’s a nearby lower area where the pipe can “exit to daylight”.

      Once the perforated drain pipe and 4″ of gravel are installed you can then set your flagstone on top using a finer, 3/8″ crushed gravel to the proper level. If you plan to have grass-joints in between the flagstone, simply lower the gravel within the joints to at least 3″ and replace with top soil (and seed or sod). This flagstone path should remain solid all year long.

  • David
    8:47 PM, 27 March 2015

    I’m installing an outdoor fire pit in my backyard and I’m planning on surrounding that fire pit with some flagstone so I have a solid surface for patio chairs and whatnot. My sod is 1 year old on top of a fairly hard dirt but I’ve never had a problem with draining. I plan on the stones being set 6″ – 9″ apart to give my bermuda plenty of room for a strong root system. Given the spacing, would you dig everything up and lay the sod back down or dig separately for each stone? What are the pros and cons for each method? Thanks!

    • Roger
      11:00 AM, 28 March 2015

      Given your situation (intended use, joint spacing, type of grass), I would simply lay out the flagstone as you’d like and cut/mark the footprint of each stone.

      You can then prep and set each stone individually. That is: make sure the outline is cut with a spade, remove the layer of sod, dig & remove soil to a depth that is 1″ greater than the thickness of the flagstone, use coarse sand or a small gravel as the 1″ setting bed, set each flagstone respective to the grass.

      The 1″ setting bed (coarse sand or fine gravel) will just make it so much easier and effective for setting each stone.

  • Sim
    4:28 AM, 12 April 2015

    Hi Roger
    Very informative.thanks for explaining so well.
    I have a couple of questions-
    1.I have a patch of grass,and I need to make a flagstone patio on it.Do I need to take out the grass,put gravel,then sand and put the stone over it or do I just put the stone directly on the grass??

    2. I tried digging just a little bit,and saw the sprinkler white pipe line under it.Do I need to take this out or just do my work over it?(I have bought a new house and not familiar with much stuff.)


    • Roger
      10:31 PM, 13 April 2015

      For a long-lasting, stable patio you’ll want to prepare the base and install as I explain.

      With regard to the sprinkler line, you’ll want to take care with that. Do you have a sprinkler guy that services your sprinkler system? If so, I’d ask his opinion and guidance. He’ll know the specifics and the role that particular pipe plays in the system. If it’s rigid PVC pipe (and if it’s white it probably is), then it could be a pressurized main line.

      Whenever we have sprinkler lines (or any utility line) going under a patio, walkway, etc., we’ll always provide a PVC “sleeve” for the utility to run through. A “sleeve” is simply a larger pipe that the utility can freely be fed through. This sleeve protects the utility and makes it possible to replace or repair the line if it ever needs to be. Also, a sleeve enables you to someday add other utilities like landscape lighting wire should you decide.

  • Sim
    11:50 AM, 14 April 2015

    Thanks so much Roger. Really appreciate it!!!!

  • jamal
    6:24 PM, 23 April 2015

    Hi Roger,

    Very useful article! I am living in the Netherlands and I couldn’t find a clear Dutch instructions for laying flagstones in a existing lawn. Sand is cheaper and easier to get then crushed little stones. I wonder if I need to water the sand before putting the flagstones on sand? My lawn is just 3 weeks old, so i think that removing a part of the grass shouldn’t be a difficult job. Could you please help me out Roger? Thank you so much!

    • Roger
      10:53 PM, 23 April 2015

      I looked up the climate in the Netherlands and it seems to be moderate, i.e. without extremes. Whereas here in the northeast US we get freezing temperatures in the winter. And this is why a properly draining base comprised of gravel is critical.

      I would think sand would be fine in your situation and climate. Try, if possible, to get a coarse textured sand.

      And if you excavated down so that you ultimately had 2 inches of bedding sand, that should work nicely for you.

  • Nancy
    8:47 AM, 13 May 2015

    Thank you for this awesome article! I’d like to make a pathway from my garage to the backyard and it’s about 50′ long (I live in NE Ohio). The neighbor’s house is slightly elevated from mine and so the rain water tends to run down into that walkway area and remain wetter than the rest of the yard, however, it’s not so much that it’s constantly soggy, just takes an extra few days to dry up vs. the rest of the yard. I don’t really want to go to the expense of installing a french drain or anything. Would I need to do anything extra before installing the flagstone to dry and make this a dryer area for the walkway? Or will laying the base properly absorb enough water to keep the area somewhat dry? Thanks so much for your expertise — it is invaluable to DIYers like us!! 🙂

    • Roger
      11:20 PM, 13 May 2015

      I think you’ll be fine with the gravel base. The flagstone should remain stable even during periods of rain and wetness.

      We have done walkways and patios in low, wet areas and installed perforated drain pipe within the gravel base. The perforated pipe collects excess water and directs it to another spot (e.g. dry-well, another lower area on the property).

      I get the feeling this is not necessary in your situation.

  • Chris
    4:05 PM, 1 June 2015

    The quarries around my area, offer an abundance of limestone/sandstone, flagstones. the same stuff they crush to make crushed rock roads.
    I can get 2-3″ thick flagstones of random dimension by the ton, very reasonably. Will this type of stone hold up for this type walkway?
    I would imagine that over time (a great deal of time) that this stone would deteriorate – but its an affordable option compared to the prices of pre-cast “natural look” flagstone alternatives at the landscaping center.

    • Roger
      9:56 AM, 2 June 2015

      I would take advantage of the natural flagstone that’s available in your area.

      At 2-3″ thick, even if it isn’t of the most solid make-up, it should work fine for the walkway. And, I might add, look a heck of a lot better than the manufactured flagstone.

      You’ll see right away how tough the stone is as you begin to handle it. It might be that you’ll need to take a little more care handling it and setting it if it’s less strong. But once it’s down and well supported by a good, solid aggregate base, you should be fine.

  • Les
    8:33 AM, 3 June 2015

    Wow, what a great site. May I ask you if there is a preferred stone dimension on a flag path? I am putting in a formal path 30 ft x 4 ft on clay (with gravel base), slightly sloping for drainage and within rolled edge metal borders. The yard where the walk goes through is an area that is 16 feet wide and along a mixed plant border. The flag spacing will be filled with breeze and the landscape plan calls for ground cover to spill over the edge. My flag pallet comes in large 3-5 ft slabs but that seems too big to just lay down as is (and trim edges for a 1 inch spacing). I saw that you said stones should be no smaller than 18″x24″, but I didn’t know if there is a ratio for the dimension of the stone based on size of path. Is there a recommended stone cut size I should use so as to not make the stones too small or make them too big/overbearing on the yard area?

    • Roger
      9:03 PM, 21 June 2015

      You mentioned a “formal” path — are the flagstone pieces cut to square and rectangular dimensions, or are they irregular in shape? I’m presuming they’re irregular.

      I would say for a 4′ wide path you could occasionally span the full width with one piece, and for the rest of the walk you’ll most likely have a combination of 2 pieces to span the 4′.

      I would suggest laying the stones out first and playing around with the pattern(s).

  • Yvonne
    2:01 PM, 11 June 2015

    Hi Roger-

    My husband and I are looking to set a material called Shenandoah indian ridge flagstone (3ft x 2ft x 24in) into the grass just as you described in the article. It will be used for a patio area where I plan on setting a table and chairs on. I like the large pieces and the material. I am concerned about the 1 inch thickness. Do you think it will crack over time? And if I cut out the grass how much gravel would I need?

    • Roger
      10:14 PM, 21 June 2015

      So do you intend to have/leave grass joints between the flagstone for this patio? It’s possible, but it’s going to be more work — both initially when constructing the patio and afterwards, in terms of maintaining it. The grass joints will begin to grow over the flagstone with time. It’s likely you’ll want to trim/maintain the grass to the original joint size — that can be “a little” work.

      The one inch thickness should be fine with a properly prepared base. Therefore, you’ll want to excavate approximately 5″ down. This will allow 4″ for an aggregate (gravel) base. The base could be 3″ of 3/4″ gravel, and then 1″ of 3/8″ gravel as a “setting bed”. Add the 1″ of flagstone and there’s your 5″ of excavation. It’s work, but this base preparation is what makes the patio stable and long-lasting.

      If you’re in an area that does not have freezing temperatures, you could make the base 2″ of the 3/8″ gravel and that should work fine.

  • m
    2:27 PM, 8 August 2015

    Hi, Roger –

    The article was great. I’m trying to re-hab my flasgstone path which is very over grown with roots, moss, etc. After I find the edges of the flagstone, the growth above it can be 2+ inches. Here’s the question: do I need to bring the flagstones up to the height of the lawn, i.e., lifting them, placing soil underneath & re-setting them? Or, am I just OCD thinking in those terms.

    Thanks for your kind response.

    • Roger
      6:19 PM, 10 August 2015

      It depends how the existing flagstone height is next to the existing grade. And when I say existing grade I’m talking about the height of the ground — not the blades of grass.

      Your stone should be level with the “ground-height”. Think of it this way — when the wheels of the lawn mower go from the grass to the flagstone, the wheels should not drop down, but roll smoothly.

      You still should have to maintain the grass edge surrounding the flagstone. It will instinctively creep onto the stone. It can be maintained with a line/string trimmer.

      If I have to cut back a couple of inches of grass over-growth on flagstone, I’ll use a knife outlining the stone’s edge, and peel away the cut portion. This is not easy and time-consuming. I would rather maintain the edge with a string trimmer.

  • Matthew
    3:51 PM, 28 August 2015

    Hello roger
    I’ve read through all of your comments and they’ve really helped. I’m doing a flagstone walkway for the first time here in San Antonio tx. My question is is there a way that you figure out how much material for the base to purchase? I don’t want to buy too little and would hate to get too much. Other than that I think I’ve got it. Thank you

    • Roger
      10:47 PM, 30 August 2015

      To calculate the amount of material you will need to cover an area you need to know 2 things: 1) the square footage of the area, and 2) the depth of the planned material.

      To calculate the square footage of a square or rectangle simply multiply the length X width. For other shapes use one of these formulas.

      Once you have the square footage of the area, and know the depth of the material you plan to use, look up the amount you’ll need on this chart. The chart is applicable for any material you plan to use.

      If you’re not excavating the entire walkway area, but rather just under each individual flagstone, you can figure slightly less base material.

  • richard mitchell
    10:33 AM, 18 January 2016

    Should the elevation of the flagstone walkway be flush with the top of the grass or with the top of the underlying soil. It would appear to be the later.

    • Roger
      12:08 PM, 18 January 2016

      You are correct. The top of flagstone should meet with the soil level. Of course this is presuming the grading in the area is fairly consistent (not up and down). Otherwise you could have one edge of the stone meeting grade nicely, but on the other end it’s not. In instances like that I’ll recommend correcting the grade(s) as part of the walk install.

  • Roger
    9:09 PM, 2 February 2016

    Years ago we used sand and had problems with the flagstones occasionally “heaving” in freeze-thaw cycles. Although “coarse” sand will technically drain well, if the sub-base (earth beneath sand) is not draining well, then the moisture is partially retained in the sand.

  • kelly
    10:50 PM, 1 May 2016

    if you are still reading these posts, need help installing manufactured bluestone on grass where there is currently no grass. I had adjust the slope (wheelbarrow at a time0 with fill and clay soil.) Do I put down the topsoil, 4 inches at least, tamp it down then set in the stones (stone dust and water) by carefully scraping away the least amt of topsoil, set the stones to soil grade then seed the area?

    • Roger
      11:35 PM, 1 May 2016

      Try not to set the flagstone on any top soil. The best scenario is gravel first, as I describe in the article. If you can find a gravel that’s 1/8 to 1/4″, that would be great. And not round gravel, but “crushed”.

      You can use stonedust if need be. It’s not necessary to wet it. Coarse mason sand would work too. We like to use gravel because it does not hold water/moisture. Here in the northeast that’s important to avoid “heaving” during the winter.

  • Debra Lloyd
    8:39 AM, 3 May 2016

    I left for the city, while landscapers installed the flagstone in bare ground. Then they seeded all through the path. They left me with enough inventory to finish what I wanted done. I thought I could trace the stone out on the earth, lift the stone and dig out…that’s ridiculous. I’m thinking I should just shovel a route 1.5″ deep and drop the stones down, cover around with earth. The landscapers did not use sand or gravel underneath. I have to do at least another 20′. I’m 66, hearty but not crazy. What’s my best route?

    • Roger
      8:55 AM, 3 May 2016

      The method your landscapers used by leaving out any base preparation is already minimal. You can’t simplify it any more than that.

      You could do it in stages (e.g. 5′ at a time) to break up the task.

  • LeRoy Haynes
    12:08 PM, 18 May 2016

    I would like to have moss growing between my stones. Any suggestions of what to use. There seems to be an abundance of moss in parts of our yard. Can that be transplanted? Can the stones be placed right on the earth without gravel? What is the risk there? My walk will slant down to the road so using a string to check the level probavly won’t work. Any suggestions?

    • Roger
      9:28 AM, 20 May 2016

      Here’s a great article all about using mosses in the landscape.

      It’s a good idea to use a small gravel or even a coarse mason’s sand to set the flagstone. Just make sure you dig down to provide enough space for the gravel or sand, and to set the flagstones flush with the surrounding earth. Use the adjacent ground levels to determine the height of each stone — in this case a string line is not needed.

  • Shirl E. Gilbert II
    1:27 PM, 30 May 2016

    I have hard clay soil(Baton Rouge, LA, what tools do I use to dig out the soil to the shape of the flagstone ??, and can you use sand for the base to lay the flagstone down on?? I see several bases, crushed rock, gravel, sand, etc, which is best ?? I’m laying a flagstone walkway from my front sidewalk to my back yard, some 80′, is that too long a run for this kind of walkway???

    • Roger
      1:46 PM, 30 May 2016

      To loosen the clay soil to remove for the base material I’d use a mattock and/or a grape hoe. With the soil loosened you can then use a flat shovel (or similar) to excavate the soil to the proper depth.

      Although you could use a coarse mason sand for the base, I’d recommend a small, crushed gravel — especially with a clay sub-base which does not drain well.

      80′ is a relatively long walkway, but this type of walk should work well.

  • Shirl E. Gilbert II
    8:53 AM, 31 May 2016

    Thanks Roger, your response is very helpful. I will start the project next weekend.

  • Patrick
    10:01 AM, 10 June 2016

    I intend to let the stones to sit on the grass for a period of time (2 weeks say) so that the grass below the stones are dead and therefore easier to remove as well the shape of the holes easily identified for digging…. would this be a good / workable idea…. I know contractor normally don’t have the luxury to wait… but as homeowner I do… do you think I should go for this “technique”….

    • Roger
      5:49 PM, 11 June 2016

      Well that’s an interesting technique you describe to mark where the stones will go and where to cut to remove the grass. And certainly that would work, especially given the time you have.

      On the job I’ll use any number of methods depending on the situation. For example: I always have a bucket of granular lime (same as used in the garden) to mark-out lines on the ground. It’s not permanent and doesn’t harm anything. I’ll scoop up some lime with a coffee can and sprinkler an outline of each flagstone. After lifting the flagstone I can cut out the shape.

      Your other question is about using a grinder to cut the sod. If you’re looking for a clean, accurate cut it’s really not necessary in this situation. Frankly, you want the cut outline to be slightly larger than the stone itself. You’ll need that little extra space to adjusting the stone. Also, within a week or two the grass will easily grow back up to the flagstone.

      The tool I use most often to cut the outline and help with removing the sod and soil beneath is a “heavy duty” spade.

  • Patrick
    10:03 AM, 10 June 2016

    One more question… I intend to use a Angle Grinder to cut existing sod out of the hole hopping to have a nice clean edge for laying the stones…. would this make sense as I never see such method from the internet and I think it might work and I haven’t bought the Angle Grinder yet… but intend to buy one just for this…. please let me know what do you think about that too. Thanks.

  • Barbara
    10:54 AM, 27 June 2016

    Roger, I laid a stone pathway thru my backyard a month or so ago thinking if I just lifted the existing layer of sod (it was only put in last summer) I could just lay it on the existing ground… Of course that didn’t work. I am wanting the grass to be between the stones but, while the stones are slightly above the ground, the grass stays way too tall after mowing over. I’ve attempted to raise the stones by adding gravel under them but I’m not sure the depth to set them at to keep the mower from hitting and the grass from taking over? Seems if they’re laid too high they would be a tripping hazard? As Patrick said above, I’m wishing I’d have just laid them on the existing grass and let them settle! Doesn’t help that the yard is a slight downhill incline.

    • Roger
      9:07 PM, 27 June 2016

      The top of your flagstone should be even (same level) as the “soil level” of the adjacent grass. This provides a smooth, consistent level for the mower to travel over — and eliminates any trip hazard.

      Invariably the grass will begin to creep over the flagstone. You can “keep after it” by trimming with a line trimmer (with some regularity), e.g. every time you mow or every 2-3 weeks. Or, wait till the grass has grown over the flagstone an inch or two and then trim each stone using a knife (or similar). You might only have to do this once or twice a year.

      As far as setting the stones on an slight incline grade: the flagstone should mirror the grade/incline and match the surrounding soil level.

      Hope this helps.

  • Sam
    2:16 PM, 23 July 2016

    Hello Roger,

    I am exploring to have a small patio (About 125 to 150 sq feet) by my basement door. Want to go economical route. Do not know what my options are. Recently, I installed drain pipes to prevent water puddle in the area. Thank you.

    • Roger
      10:07 AM, 25 July 2016

      So smart you’ve taken drainage into consideration!

      In terms of your choices, of course there are many. I would choose a material 1) you aesthetically like, and 2) can be dry-set (i.e.) set without cement.

      I suggest visiting stone yards and masonry supply places for ideas and suggestions. We have several in our area, and they have displays showing exactly how each material looks. I often meet with homeowners at these places to choose their materials. Also, bring photos with you to show the setting where the proposed patio is going.

  • Tim
    3:55 PM, 15 November 2016

    Installing flagstone walkway on established yard. Should I remove area with sod cutter, then cut out and apply base

    • Roger
      11:11 PM, 15 November 2016

      You could either remove the sod throughout the entire flagstone path or use the flagstone pieces as templates and just cut the sod out within that shape.

      That’s a call you’ll need to make based on personal preference. But here’s a few things to consider.

      If the existing sod/lawn is thick and healthy, you may want to preserve that and cut out for each stone.

      On the other hand, if the existing sod/lawn is thin and weak it probably makes sense to treat the path as one and remove all the grass.

      Another way to look at it (again, it’s personal preference) is leaving the existing lawn and just cutting out the grass underneath each stone is tedious work. The thinking here is you’d rather take the time and effort at the end patching in with new sod or top soil and seed.

      You can see that the method you choose depends on the site conditions, how long the walk is, and how you would prefer to work.

  • Carrie
    5:31 PM, 2 February 2017

    If a flagstone path is install can you drive on it say backup a trailer to move furniture? I don’t want to ruin it but trying to figure out hoe close I can get to the house. Builder says “it was installed properly”. Whatever that means.

    • Roger
      8:42 AM, 3 February 2017

      I would not drive over a flagstone walk — even with a trailer. You can place plywood over the flagstone and that would protect the flagstone and disperse the weight over a larger area. If you don’t have plywood, perhaps you can borrow from someone. Builder?

  • frances
    1:40 PM, 3 May 2017

    Roger, We are laying an area about 4′ by 50′ of flagstone on a part shade area. it’s been dug 4 inches deep already ( it was regular soil)
    we want to lay the flagstone with enough space in between to plant moss or some type of ground cover. I am a bit confused on what material to use and how much needed to make sure the stones are firmly set but my plants can grow.
    what I am thinking is to add 2 inches of packed sand to set and level the rocks on then sweep more sand on top to fill the gaps between the that good environment for plants to survive? how deep should I plant them below the sand?
    should I use a different material instead of sand like crushed granite?

    Ideally, i would like a material that will get hard but I am unsure if I can plant in that material or if the plants can spread.

    I realize this is an old post, I am hoping someone can respond.
    Thank you all in advance for your help.
    Blessings to all!

    • Roger
      11:27 PM, 3 May 2017

      So you’ve excavated throughout the entire 4′ x 50′ area — and about 4″ deep. Your intending to plant between the joints.

      In our area of the NE we excavate a bit more and then use a gravel for our base. We do this because of the freeze/thaw factor. If we did not excavate deep enough and/or used a base material that retained moisture, then the freeze/thaw cycles would likely cause heaving.

      If you’re in a climate where freeze/thaw and heaving is a concern, you may want to at least use a small crushed stone/gravel, such as 1/4″ or so. Perhaps the crushed granite you mentioned would work.

      I would then set each flagstone using the gravel, but try to minimize the amount between the stones (in the joint spaces). Certainly there will be some spillage that falls into those spaces. Ultimately you’ll want to use a good soil to plant your moss and/or groundcovers in — and fill the balance of the joints with. If some of the setting gravel happens to mix with your planting soil, it should not be a problem. Just try to keep it to a minimum.

      Over time the groundcovers and moss should grab hold and establish — firming up the soil within the joints.

  • frances
    11:20 AM, 5 May 2017

    Wow, never thought you would actually answer! Thank you!!!! We live in OKC Oklahoma. It does get fairly cold, we are zone 7.

    Reading your suggestions and what I have read, To make sure I understand, I should dig a few more inches and add small gravel, pack it down and level the stones on top of it leaving 1 1/2 – 2 inches between rocks. Then fill the gaps with good soil to plant the ground covers.

    6 inches deep, 4 inches gravel, stones on top and sweep dirt in the gaps …. No sand at all?

    You have no idea how much I appreciate your help! Kind of excited I got an answer! Have a blessed day.

    • Roger
      9:48 PM, 5 May 2017

      You’re right on track — except I might make the joint space wider if you’re planting groundcovers — more like 4″ or so. We have found much greater success with groundcovers (and the like) when the joint spaces are not too narrow.

  • Sabrina Cherry
    12:56 PM, 21 May 2017

    Hi Roger I live in Texas and we are creating a porch out of flagstone in front of our front window. I have two questions for you. So imagine a full moon and divide the moon into 4 parts. Take one of those parts and that’s the shape of our area that we want to create this porch. How do we measure this area since it is not equally squared off? Second question is…is it ok to use sand beneath the flagstone? Thanks

    • Roger
      11:05 PM, 21 May 2017

      The way you describe the area it’s a quarter of a circle. To calculate the square footage of that quarter circle, you would calculate the square footage of a full circle (based on this quarter circle measurement) and then divide that by 4.

      Here’s a nice square footage calculator tool online. Click on the “CIRCLE” tab in the navigation bar. Now, just enter the radius (measured in feet). The radius is half a circle — therefore, measure one of the flat sides of your quarter circle area and that’s the radius. When you hit the blue “Calculate” button you’ll see the “Result,” i.e. square footage of the circle. Now, just divide that number by 4 and you’ll have the square footage of your quarter circle area.

      In terms of using just sand to set your flagstone: if you’re in an area that does not freeze you should be OK.

  • Connie
    8:58 PM, 10 July 2017

    I live in Ky. What is the best base based on my location. Sand or gravel or both? Using creek rock.

    • Roger
      9:56 PM, 10 July 2017

      Here in NJ we have a stone we call creek flats. They’re really nice — rounded on the edges and do make a beautiful path. But try to use larger ones if possible. I have found that the smaller ones do not have enough mass & weight and can easily come dislodged.

      I’m not a fan of using just sand as a setting base — especially if there can be freezing temperatures. A small, crushed gravel really works well. The gravel pieces can and should be small (around 1/8″).

  • Stephanie
    8:41 AM, 11 July 2017

    Good morning, We live in South Central PA and want to install a flagstone patio with grass (or moss, aromatic thyme, etc) joints. We removed existing, poorly installed flagstone and paver patio so we are basically starting from scratch on an excavated space.

    Am I correct that you would recommend setting the stones in small gravel only? We have read other articles that recommend a gravel base that is tamped,and then sand. However, I think you are saying that could cause heaving during the freeze/thaw cycle. Its a large space and we/d really like to do it right the first time. How deep should the gravel base be and should it all be the 1/8″ size?

    Also, do you recommend closer to 4″ between the stones?

    Lastly, for the joints, do we just use a blend of topsoil and grass seed?

    Thank you!

    • Roger
      10:06 AM, 11 July 2017

      For dry-laid flagstone we like to have a base of 3/4″ crushed stone (approx. 4″ deep) and then use a small crushed stone (1/8″ or so) as a setting bed for the flagstone — perhaps 1″ deep. This ensures moisture will not collect underneath the flagstone and cause it to heave in winter. Here’s a pic of a dry-laid patio being installed. You can see the gravel layers.

      One challenge you’ll have is getting the grass to grow in between (because of the gravel base). Keep the joints 4″ wide or greater. After the flagstone is set remove some of the gravel in the joints without undermining the flagstone. Replace with a good top soil and then seed into that soil. Watering will be crucial, especially in this summer weather. Keep the soil moist for germination. And then, of course, you’ll need to monitor the grass and make sure it gets adequate moisture all along.

  • Roger
    7:25 PM, 11 July 2017

    I was speaking with a fellow designer/contractor today and your situation with a flagstone patio with grass (or other vegetation) between the joints came up. After some discussion we came to the conclusion that you could use all 1/8″ crushed stone as your base.

    The feeling is you still should have adequate drainage, and at the same time it’s very possible the roots of whatever you plant in the joints will grow into the smaller gravel, which is a plus.

    You’ll still want to do what I talked about in my previous comment with regard to removing as much gravel from the joints (w/o undermining flagstone) and replacing with soil.

  • Sim Mac
    10:45 PM, 12 July 2017

    Hello Roger, I have a side yard that is so soggy I want to make a pathway with cobblestones to the gate. How would I go about doing that? In Southern CA.

    • Roger
      9:13 AM, 13 July 2017

      To deal with the soggy ground conditions I would use a gravel base. But one important thing I would add is to use filter fabric between the subsoil and gravel base. This will ensure the gravel does not mix and migrate into the soggy subsoil — drastically improving the long-term integrity of your walk.

      Here’s an article I wrote on a bluestone pathway with construction like I’m suggesting.

  • Brad
    3:00 PM, 8 February 2018

    Wow! Roger thank you so much for the diligence and completeness of you replies. Great work here, and you’ve made my planning and execution so much easier! Thanks again.

  • Teddy
    2:00 PM, 17 May 2018

    This is a great post, thank you for taking the time to write it up. I’m about to start a flagstone pathway from my back door to the gate entrance at the driveway. It’s not a big stretch, however we have some massive Maples in our yard. I figure I’ll have to cut out some of the roots during excavation.

    From reading the comments this is what I’ve gathered:

    Excavate 6 inches
    Compact dirt (Am I leveling / pitching the area during this step?)
    Dump 4″of crushed aggregate stone 1/4″ into the area
    Compact Stone
    Lay stones, level and pitch as you go
    Brush soil in between 4″ joints
    Apply seed/ground cover

    Does this sounds right? We’re in Eastern LI and our due to the trees are yard is BUMPY.

    • Roger
      8:45 AM, 18 May 2018

      That’s a good summary of the steps.

      Maples are surface rooted, so I can imagine what you’re dealing with. It may be impossible to excavate 6″ throughout with the roots. So you may have to compromise in spots.

      The other strategy would be to do the best you can with base preparation, and if necessary build the walk slightly higher than existing grade. This strategy works if you have enough room and the grades cooperate where you can add top soil to meet the higher set walk. If the area is small and by raising the grade (with soil) it looks peculiar or interferes with proper grading and runoff/drainage, then that strategy won’t work.

      To answer your question, you’re not “leveling/pitching” the sub-base. It’s the final stage of setting the stone(s) where pitch comes into play. Observe the natural (and proper) grade of the area, and set the stones to “work with that grade”.

  • Mark
    11:36 AM, 4 December 2018

    Hi there!

    About to install a flagstone walkway in my grass, about 25 feet long, 2 feet wide. I have already bought a few of the stones, but they are about 3/4 inch thick, not the 2 inch that you recommend. Will that be ok? Also, just so I am clear, I am to dig down 5-6 inches deep of each stone, add gravel just within the parameters where the stones are placed, but try not to disturb the grass or soil in between stones? Then set the stones so that the top of the stone is level with the soil?

    What happens when the grass grows around the stones, will that make the stones look like they are sunk down farther, and the grass will be an inch or two taller than the stone? Is it best to use a weed wacker or something similar to keep the grass shorter around the stones?

    Thanks for this tutorial it is a big help!

    • Roger
      9:48 AM, 28 December 2018

      We use thicker flagstone (2″ or so) because it gives more weight and mass, which helps anchor each stone and minimize it moving. If you’re using 3/4″ thick stones I’d suggest using larger pieces, again to give more weight and more surface contact with the setting bed.

      Also, be extra careful setting each stone to eliminate any wobble. Any wobble just gets worse over time with foot traffic and things like the lawn mower running over it.

      Ideally you want to remove the soil just where each flagstone sits. But that can get tedious and challenging, especially if it’s a long walk. We have at times excavated the entire walkway area, set the stones on the setting bed (gravel) and then removed “some” of the gravel between the flagstone and replaced with topsoil. You have to be careful, though, that you don’t remove too much gravel or you’ll undermine the flagstone. I would first try to excavate just under each stone.

      The soil level should come to the top of the flagstone, then re-seed. This helps stabilize the flagstone, especially once the seed germinates and establishes its root system. But yes, you’ll need to maintain the grass as it will want to creep onto the flagstone. The stringline trimmer will help in your weekly or every other week maintenance. But maybe once a year you may find you’ll need to take a knife and cut back the creeping grass back to the flagstones’ edges.

  • Heather
    10:25 AM, 17 April 2019

    Hi Roger,

    I have e a properly laid flagstone path, but the installer only gave me soil 2 to 3 inches deep before I hit that gray setting gravel. I wanted to plant Irish moss between, but dont have the soil depth needed. Do you have any recommendations on what to plant when you have shallow roofing depth? Thanks!!

    • Roger
      12:03 PM, 17 April 2019

      Planting between flagstone is such a great look, but it can be very challenging to sustain. And you’re right, a big part of the “success puzzle” is having adequate soil. But of course there are other variables such as exposure. For example, full sun is tough on any plants with limited root development — and add to that the heat from the flagstone. And that leads to the moisture and irrigation issue. These are just a few of the challenging variables.

      I have a few projects where we made the attempt to grow plants in the joints and eventually gave up. In those instances we replaced with grass (and even that can be a challenge depending on conditions) or we chose to fill in the joint with something “not living”. For example, stonedust or one of the new polymeric sand jointing products. On one job we removed the soil to the gravel base level, set small decorative stones and then filled in with the polymeric sand product. Turned out to be an interesting look. 🙂

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