Installing a flagstone patio or path can give your landscape design a huge boost and really impress your guests (or customers if you happen to be a pro).
I love the natural feel they give to a landscape design. Instead of just using boring old paver blocks or even cement, flagstone will make your backyard more interesting and unique.
In this article, I’m going to share exactly how to install a flagstone patio (or path) easily and without the use of concrete or special tools.
Just like everything else, there is more than one way to get this job done. The method I’m showing you is optimized for a balance between simplicity of installation, longevity, and a high-quality professional look. So, not only will it be easy to install, it will last a lifetime.
Let’s get started…
Quick Disclaimer: Make sure to check local codes before installing anything in your home as your area may require a different process for building a patio. And be sure to use the proper safety equipment while using tools (gloves, eye protection, etc.).
Also, the links below are affiliate links. That means I receive a small commission if you click on them and buy (which I really appreciate). This does not cost you anything additional and it allows me to put out free information like this.
You’ll need the following tools:
- Flat nose shovel
- Spade shovel (this one’s pretty cool)
- Metal rake
- Wheelbarrow
- Hand Tamper or Plate Compactor
- Line Level
- Mason’s Line
- Stakes (wood or steel)
- Measuring Tape
- 4′ Level
- 5 gal. Bucket
- Small hand shovel
- Angle Grinder with Diamond Blade
- Mini Sledge
Step 1: Plan Your Patio
Besides the obvious considerations such as patio placement, size, and shape, here are a few more things to consider that aren’t so obvious.
Grading: You must build your patio so that it drains properly; otherwise, you’ll end up with puddling problems later. Never build your patio perfectly level. Instead, build it at a slight angle, so water easily drains off of it. That angle will be about 1/8″ of drop per foot of patio. You’ll want to take note of the existing landscape drainage on your property and work with that. (Watch the video for a more thorough explanation)
Stone Size: The bigger the stones, the less work you’ll have to do puzzling them together. However, bigger stones are heavier, thicker, and more expensive. So, find a stone size that works for you.
Stone Thickness: Thinner flagstone will tend to crack under heavy weight. Thicker flagstone is heavier and more expensive. If you’re building your patio in your backyard, then 1.5″-2″ thick flagstone is perfectly fine. If you’re building a driveway out of flagstone, you’ll want to go with stone at least 2″ thick and ideally thicker.
Irrigation Lines: If you plan on installing an irrigation system or even a gas fire pit, run the lines before building the patio. And, be sure to “call before you dig” so you don’t hit any existing lines in the process of building your patio.
Step 2: Dig
You’ll need to dig down far enough to accommodate 3-4″ of packed gravel base, 1″ of leveling material, plus the thickness of the pavers. That means in most cases you’ll want to dig down about 6″.
In some cases, you can add dirt surrounding the patio, but you’ll need to plan that out before you get started. If the patio is close to a building, don’t build up too high, or you’ll end up having dirt right up to the siding – which is a great way to get termites.
6″ is quite a bit, especially if you’re building a large patio, so you’ll want to consider what you are going to do with the dirt.
Step 3: Add 3-4″ of Packed Gravel Base
Unless you don’t mind an uneven patio, the gravel base is critical. It will keep your patio nice and flat for the long term and support your stones so they don’t crack and break. This is the patio’s foundation, and if you want a professional finished product, don’t skimp here.
Add the gravel 2″ at a time, and pack it down well before adding more. You can back it down using a hand tamper or a plate compactor. Either way, just make sure it’s packed down really well.
If you’re building a flagstone driveway, you’ll want to go with 6″ of gravel base at a minimum.
Step 4: Install 1″ of Leveling Sand
Actually, you don’t want to use sand because you’ll need to walk on this layer a lot, and as you know, sand moves when you walk on it. So instead, you’ll want to use some crushed rock that includes the screenings.
Where I’m from, the best stuff to use is called Decomposed Granite (DG). This stuff looks similar to sand, but it packs down much better so you can walk on it. Since it’s composed of both bigger pieces of sand (1-2mm diameter) and fine dust, it’s able to pack down similar to dirt, but it’s still easy to level out, and weeds have a hard time growing in it.
Since this is the final layer before you start laying stones, you’ll want to make sure it’s flat and graded properly. So, use a mason line tied between stakes in the ground and a line level to set the grading just right and ensure a flat patio.
Once it’s level, spray with the hose to get it damp and pack it down thoroughly. Level again if you have to.
Step 5: Puzzle Together The Flagstone
Start by grabbing the larger stones and placing them around the perimeter of the patio. You want to use the larger stones on the outside because smaller stones will move and shift with time. Large stones will lock the smaller stones toward the center in place.
Then, start adding the rest of the stones to the center, working toward the middle of the patio. Cutting the stones is time-consuming and dusty, so spend a few minutes trying to puzzle them together, so you have to make as few cuts as possible.
Here’s a quick tip: The tighter and more consistent you try to make the seems, the longer it’s going to take because you’ll have to make waaaay more cuts. If you don’t mind bigger gaps, you’ll save a ton of labor, and you can get by with fewer stones to save some cash.
To cut the stones, you can use anything with a diamond blade on it. You see me using an angle grinder in the video, but there is a much easier way to cut the stones, which is to use a concrete saw with a larger diamond blade, as I demonstrate here.
Step 6: Level the Flagstone
Oh, you thought you were done? Ha! There’s still one step to go – leveling the stones.
Unless you don’t mind the flagstone shifting around as you walk or constantly tripping on edges, you’ll need to go stone by stone and level each one out. Since many of the stones will be uneven on the bottom, you’ll need to add some DG (decomposed granite) here and there and remove it in other places. You might even have to pick up a stone and make adjustments 5 or 6 times to get it sitting properly. That’s just how it goes.
I recommend having a bucket of DG and a small shovel handy, so you can quickly add and subtract DG as necessary.
To level each stone, start by placing a 4′ level on the stone to see how it sits relative to the grading you set and the other stones. Then simply make adjustments from there.
This step isn’t fun, but it gives you a very professional finish if you take your time (and lots of breaks).
Step 7: Fill In The Gaps
Now comes the easy part – filling in the gaps. You can use whatever you want for this step. You can use soil which would allow you to plant moss or something in the gaps. Or, you could just use more DG, which will help keeps weeds at bay.
Whatever you add, just make sure and spray it down with a hose to lock in the stones, and you’re ready to enjoy your hard work!
How to install a flagstone walkway
Building a flagstone walkway or path requires the same exact process.
Here’s a video that will show you this entire process compressed down to just 5 minutes. It should also be helpful for building your patio as well.
Q&A
Do I need a 4″ base if I’m just building a flagstone pathway?
It depends. The base is there to keep the stones from shifting and becoming uneven over time. A little movement in a pathway usually isn’t a big deal, so you could just do two inches of base material if you want. Or, just eliminate the base and do two inches of decomposed granite.
Where do I get the materials?
The flagstone can usually be purchased at a local nursery. Shop around, though, because some places have a much better selection.
The gravel base and the decomposed granite (DG) can also be found at most nurseries or rock yards. If they don’t have DG, just ask them if they have something similar. Chances are, they’ll have the same thing, but they’ll just call it by a different name.
Do you have a video on building the retaining wall in the video?
Sure do. You can find that tutorial right here.
Have another question? Let me know in the comments below.
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Very nice how to, one of the best and extremely helpful for a home owner seeking to so a DIY.
Have viewed alot of procedures online for laying flagstone. I think yours is the best. Lays it out simply. Well done sir. Thank you
Hey,
Great post you very well explained how to use a flag stone in building a patio. I’ll take note of this and try using it next time. Right now my patio is built with brick stone which is also a good flooring material
Keep it up
Zac
Thank you for this instruction. I am going to try it on a patio/walkway combination. If it turns out well I will post pics 🙂
What kind of sand should a person use to set flagstones in a patio. Also how much sand should be used under the stone? Will playground sand work?
Decomposed Granite, not sand.
Mulch and Dirt yards sell crushed granite. Google it or look it up on the map, and call one close by. One place quoted $65, and another quoted $85 per yard (which should equal about 2,000 pounds) and should fill the back of a pick up truck.
We are putting in an above ground pool, and I accidentally bought masonry sand, and then had to by bank (orange clay sand with no roots for the pool). Bank sand is $18, and masonry sand is $25 per yard. The place I ordered the sand from will deliver in a dump truck if your within a short miles distance near them for $75.
Can I use the masonry sand under the flagstone? And then the granite on top? Or is the masonry sand to pose-able? Like it will slip and move too much. I don’t know what I can use the masonry sand for that’s in the back of my pick up.
Dan where have you been? I’ve been searching for a practical way of laying flagstone since my first home purchase in 2010. My feverish search waned over the years but the fire never went out and now here you are. Thank you so much for the information, demonstration, ideas and video. My flagstone project can now begin.
Very formative instruction. I got a question: can I fill the flagstone gaps with cement/mortar? I want a match with other laid area.
You’d have to lay the stones in cement, too. Otherwise the joints would split and crack pretty much immediately.
Thank you for the instruction! If you wanted to grow some moss\grass in between the stones would you use dirt in between the stones instead of DG? Thank you!
Yes, dirt is fine between the stones, just not under them.
Very well explained.
How does one go about determining the amount of gravel, dcg, etc.
Is it a simple square footage calculation or is the compacting factor in?
Overall, an excellent presentation and very helpful, especially the advice on using DG as the setting base vice sand. But (small but, not a big but) the artisan in me winced when you said cutting (to fit) the stones “sucked.” To me, that’s part of the art of working with irregular flagstones. I note that virtually all your cuts, presumably with the electric cutting tool, were pretty much perfectly linear. While I am not for making a project like this needlessly more difficult than it has to be, to me there is a craft, a skill, to be learned and followed here and it’s and old and honorable one in terms of masonry and working with natural stone. If speed and ease are the the major considerations, one should hire a crew to come in a lay down flagstone-style stamped concrete. Please don’t encourage shortcuts. Allow for artistry in the process. And thanks again for the video.
Agree!
Hi Dan,
Fantastic video!. Simple, straightforward and just enough talking to get your point across!!!! Quick question for you. Could you use polymeric sand for the gaps between the flagstone?
You can, and my mom did on hers. It cracks though because the stones move a bit.
Can you use pea stone under your flagstone and when done and cement to fill in the gaps????
I wouldn’t recommend it.
Dan
Can you be a bit more specific on the gravel? Crushed? Size? Do you put a separation fabric between gravel and stone dust or let it fill the gaps?
I second Eric G’s question:
“Can you be a bit more specific on the gravel? Crushed? Size? Do you put a separation fabric between gravel and stone dust or let it fill the gaps?”
I also have that question – what size gravel?
It’s a type 2 gravel base – the same stuff they use underneath roads and pretty much any paver patio. The rock yard you go to will know what to sell you.
Dan
Thank you for a great tutorial. Wish you were in Northern California I’d have you put one in my backyard.
Simple but very complete. Question, how do you treat the raw edges that don’t fit next to a wall, or house? Some joints will lead out to the edge, so how would one go about filling them in so the joints don’t wash away? In your picture, I don’t see any edging material or the like.
Many thanks, I’ll be ordering materials next week!
I just use the larger stones around the edge so they don’t move easily and they stay in place well.
Great tutorial, thanks for taking the time to help us all out! Question, if I wanted to use mortar for the joints instead of DG, would that be ok in your opinion? Or would it lead to cracking issues over time? Thanks in advance.
JG
It would crack unless you set the stone in concrete.
I have laid flagstone many times directly on the crushed gravel, sand is nice, but you must be careful not to use too much and mostly only use it for easy leveling. Also, a polymeric ‘dust’ that is made for flagstone joints is a nice finish. It hardens like mortar but flexes with moisture and lasts a long time 🙂
You guys do amazing work!
Flagstone was laid last year,professionally(?) Over the winter, a lot of the polymeric sand loosened a lot. I have swept a lot of it away. Should I apply more more of the sand or use the granite as you suggested? Or will they combine? Thanks.
HI Nancy,
What did you use underneath? There are different ways to install flagstone for different applications. Did you use sand or spec mix right Thin set underneath? If you used a concrete type base then you would want to use the same for the grout. If you used polymeric sand in the joints and you used a sand or DG under, then you might just want to re apply the sand which is very easy to do. I’m installing Flagstones now on a driveway, and we’re using Spec mix, and will use the same spec mix between joints. In the backyard, I’m installing pavers over a rock base and fine sand. Then I will use polymeric sand for that application. I hope that helps.
Jason – IMEU Design and Construction
Dan,
Do you do any over build on your gravel and DG base? If so, how much?
Thanks
Great work Dan. I”m very impressed with the finished product.
We have flagstone in our backyard in Gilbert, AZ, and the large red pieces are literally disinigrating into dust..every time we sweep it it’s a huge pile and about a week later we have another pile to sweep up. It’s only the pieces that are red.. any recommendations? I’m wondering if theres a seal missing or something?
Thanks!
This is very helpful. I’m creating a small patio approximately 6×6. it will be on top of concrete that is in good shape. Will I still need the gravel layer.
No need for gravel if you already have a base.
Dan, I just had a beautiful new alumawood patio cover installed. Now I can see how awful the concrete patio, with its cracks, looks. Can the concrete be replaced with flagstone without having to rip my brand new cover out? Or, can flagstone be installed on top of the concrete?
In case you still need an answer, I’d look for ways to remodel or improve a concrete patio. You can even get old slate roof tiles and mortar them in place on top of a concrete slab – there are lots of relatively cheap options, when talking about concrete.
I’d love to hear more about mortaring slate tiles onto concrete. I’m looking to cover a concrete patio, and I’ve sourced some cheap flagstone, but I’m also swimming in slate roof tiles and would love to know how I might incorporate those.
Dan
I have a raised flagstone patio the outer edge pieces move a good bit, is it possible to mortar or concrete the edges down, or is there a better way
Can you use a 14″ power tamper to set the flagstones in place? Just wondering if the power tamping will crack the stone.
Hi Dan,
Thank you for your help! I’m on to my second project using your guidance. One thing I’m not clear on that I’m hoping you can help to clear up. If the base is graded properly before laying the stone, are you saying that you then lay the stone level, i.e. not at a grade? I’m not clear as to why you would use a level to arrange the stone if you’re expecting them to be on a grade (not level).
Thanks for your help!
Is decomposed granite also known as 3/8 minus?
Thanks!
No, it is only known as decomposed granite or “DG”. 3/8 minus would be a crushed rock/gravel product.
Great info! Thank you. Question: In terms of water damage to my foundation is it better to have the flagstone come right up to my concrete foundation or should I leave a gap filled with pea stone or gravel? On that note should we tilt the entire patio away from the foundation?
I don’t see any need to leave a gap. And yes, always grade so that water flows away from your house.
We are building a flagstone patio. There is little slope and underneath is rock shell mixed with clay. We do plan to dig it more to fit 4 inch rock base layer 21a plus 1 1/2 inch sand paver or dg. Looks like we may need another row of brick wall to support the base. Am I correct? How to go about drainage location? Do I need to dig a row in lower section and put one layer with cement brick with drainage and than our brick wall?
I have steps going up the center of a retaining wall from a sunken patio. Id like to run a flagstone path at the top as a top step. The top of the wall has an 8 inch block as the base of steps filled with gravel. Could I put a flagstone as the top step? And since there’s block already, get away with one or 2 inches of gravel just there and resume 4 inches etc on the rest? Basically is the block a decent enough base for a section of the path
Hi–This was very helpful. I’m going to try to do a small patch outside my back door–4’x4′ flaring out at the front with a trim of bricks around it. Ques. #1–should I put down a weed screen first after I dig? #2 What is the difference between gravel and the Decomposed Granite?
I wouldn’t worry about a weed barrier. Gravel has bigger rocks in it. DG is mostly small round rocks from granite.
Thank you very much and pleased you are still answeing questions even tho it’s been so long since you wrote this. I am going to put 3/4 gravel as you suggested, then DG.
Do you recommend stabilzed or UNstabiled? My local store said to used “stabilzed” on the whole thing, but last time I did this it was not permeable and had puddles and mud. Yes, I graded the best I could, there aren’t many options to direct the water to and in my area they want water to seep into the ground, not into the street. I was going to try UNstabilized and then stabalized on the top between the flag stones. Whatcha think? And thank you again.
I’m not sure what stabilized means. Does that just mean with the screenings? If so, then yes, you want stabilized.
Thank you for the video. I’m starting an 11′ x 11′ rough circle. Had river rock (2′-3′) in the area. Dug out a lot of it. The area is surrounded by the river rock.
I’ve put 3″ of sort of a pea gravel, but not round pieces. (Neighbor had it for free) For the top, I plan on using 2″ deep red sandstone/flagstone pieces, from Lyons, CO. Should that work ok? (And, I like your idea of putting the larger pieces on the outside for stabilization.)
Dan – I agree with all of the comments already posted here regarding how awesome your video is compared to the many others that I’ve watched. I really feel like I am well prepared to tackle something like this now. Quick question: We are about to put in a walkway from our front porch out to the sidewalk on the street. We would like to put some sort of stone edging around the walkway. Can I just set the stone edging in the ground following the same instructions that you provided for the flagstone, or do I need to cement the edging? I feel like I should be able to do it without concrete, but many of the videos I’ve watched about a border use concrete to set the border. Thanks in advance for your answer.
Very helpful! Appreciate the emphasis on the base road & NO sand!
I also found Devin Devine at devineescapes.com to be very helpful. Gives a lot of details from the base up!
Sorry…one more thing….the walkway that we are planning to put in will be a flagstone walkway, with a stone border on the edges. Thanks.
This has been so helpful and we’re following your instructions! I’m a little stuck on the DG layer. I added layer of DG and maybe need to do one more. I spread it out, wet it and tamped it down. However today, the DG is really hard! Are we not supposed to lay the DG down until the flagstones are ready? We were hoping to spread out that work over the course of several days.
You want the DG to be hard so you can walk on it. You should still be able to manipulate it with a shovel though.
Yeah I think it’s making sense to us now. Now that we have a mostly even DG layer we can use loose DG to place and level each individual stone. Guessing the weight of each stone plus water will help set it in place?
Loved the video. Have all my base and dg down amd ready to lay stones. Problem though, excavation and base building took longer than I thought and won’t be able to finish before going to cottage. Can dg or in my case limestone screening get wet? Would putting down a tarp suffice? Any advice would be great!
Yes it’s fine if it gets wet
Very helpful video. Especially liked your directions on the base material, DG and slope technique. I only wish I’d seen this a year ago. Now the job is started. There is barely 1-2″ of base rock. 270 sq ft and only 2T of base rock. Then after quickly packing they put the sand down (not a coarse sand). In some places it would need 3″ of sand to bring to level to meet with pool bullnose. I’ve stopped that phase. I feel like the sand should be broomed into piles and carried off. After seeing my son-in-laws project, using the DG, I’m thinking this Dakota & Red Canyon flagstone would be better set on DG and gaps filled with same DG. And the slope was not clearly done. In fact, they were going to put a drain 15″ from the house wall–which would indicate sending rainwater toward the house. I am will to restart with whatever I need to do–if it takes another year. Hope you can have some advice for me. My base ground, under the rock base is hard clay–except around the pool apron there was a lot of coarse sand–which I think may have caused the pool deck to drop 1/2″ to 1 5/8″.
The drainage is very important. That would justify redoing it for sure. You never want water draining toward your house. You may be able to get away with a small amount of base material, but just understand you are risking the stones heaving up in places down the road.
Thank you Dan, for your much appreciated reply. So, I’m thinking you would get the sand out and rebuild the road base as needed. Then top and fill with DG. That just makes sense to me–from various sources. Cutting the flagstone is a little scary but I will review your guidance on that. One last concern, IF I can not finish this before the rains come, I’m wondering if I can DG fill the flagstones that are in place and complete the rest as weather permits. Who says we can’t keep learning–at 78. Thank you so much!
So we are just about done cutting the flagstone. There is a compacted DG base and we have plenty of DG to do the leveling. Just one question:
Should the DG be dry or damp or wet when leveling the flagstone for final placement?
Thanks much.
Damp is good. You don’t want it too wet because then it gets stuck on everything. Dry is fine too.
Thanks for the easy to follow instructions for installing a flagstone patio. The one piece of info I haven’t found is a maximum or minimum width the gaps should be between the stones. I have removed the poly sand that was used when the patio was professionally installed 5 yrs ago because the flagstone has heaved and pieces have broken off of the slabs. I know there is a recommrnded width for gaps when using poly stone; is there a minimum or maximum gap width if using crushed stone? Thanks in advance.
It really doesn’t matter. Just do it to your preference. Smaller gaps will require more cutting, bigger gaps will have more placed to grow weeds.
Very good video and instructions, Dan! We left 1.5-3″ gaps (mostly 1-2″ gaps) and filled with DG, The big problem is the legs of our patio furniture pierce the DG. How do you really tamp down the DG between the small gaps? Any special technique for that? Thank you!!
Thanks for the instruction.
what about the need for metal edging around the patio? Can I lay the flagstone flush with the grass and expect them to not move, or do I need edging to secure it?
Place the larger stones toward the outside as I discuss in the video. No edging needed.
Question on grading: per your instructions, the dirt, concrete, and DC should be graded. What about the flagstone’s themselves? Should these be level all the way across the patio or do they also need to be graded?
That is the most important part to be graded because otherwise the water will pool up.
I noticed you don’t use any retaining wall when you dig for your sub base. I dug out 8 inches and had to retain the sides with boards. Now I am thinking about curved edges instead of square. Any advice?
They sell flexible plastic edging for locking the edge of a field of pavers. You can get it at either of the big ome improvement stores. In use, it is generally spiked down with foot long spikes, on top of the sand base prior to laying the pavers or stones.
What do you suggest sealing with after the top layer of DG?
I don’t recommend sealing. I try to use chemicals as little as possible, unless they are absolutely necessary.
Dan, should I be grading each later? The dirt base, the gravel and the DG? Or do I start grading st a particular layer?
All layers should be graded.