How To Install a Flagstone Patio (2022)

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:

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)

(Video) How To Install A Flagstone Patio (Step-by-Step)

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

How To Install a Flagstone Patio (1)
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

How To Install a Flagstone Patio (2)

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.

(Video) Hardscaping: Flagstone Patio Installation!

Step 4: Install 1″ of Leveling Sand

How To Install a Flagstone Patio (3)

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

How To Install a Flagstone Patio (4)

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 stoneswill 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.

(Video) Don't attempt BASE PREP until you see this video! Base Prep basics to make your project last.

Step 6: Level the Flagstone

How To Install a Flagstone Patio (5)

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

How To Install a Flagstone Patio (6)

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.

(Video) How to install a Flagstone Patio. Back to my Roots

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.

(Video) Installing Flagstone Walkway. I suggest to watch at speed 1.25 or 1.5.

FAQs

What is the best base for a flagstone patio? ›

The Bottom Layer of Base: Crushed limestone is the best material for the bottom layer of a patio base. Using a metal bow rake, spread the limestone one inch thick over the entire area of the patio and tamp it down. Repeat this process until you have four to five inches of compacted limestone.

What is the best material to put between flagstone? ›

Rocks: You can use small rocks to fill large gaps, and gravel or crushed rock can be used to fill smaller gaps. Mulch: Bark and lightweight chunks of mulch are a great option for in-between flagstone. Cocoa shell mulch is small and curls, for a unique look.

What's the best way to install flagstone? ›

It can be laid on a dry bed of sand and gravel or it can be mortared to an existing concrete slab. There are also three options for filling the joints between flagstones. Joints over a dry bed can be filled with sand or can be planted between with groundcover, or can be mortared for a smooth, solid surface.

Can I lay flagstone on dirt? ›

One of the best things about flagstone is that you can easily lay it on dirt. Flagstone is generally heavy, making it the perfect material to lay on dirt surfaces directly. All you need to do is smooth out the soil, place the stones, level them, and fill in the gaps as you piece them together.

How do you prepare the ground for laying flagstone? ›

How To Install A Flagstone Patio (Step-by-Step) - YouTube

How thick should flagstone be for patio? ›

The stones should be at least 1 1/2 inches thick for strength; 2 inches thick is better. Note that "flagstone" merely describes the stones' wide, flat shape; flagstone comes in many different types of stone.

What do you put under flagstone? ›

Fill between the stones with topsoil to within approximately one inch of the tops. Cut sod into strips and press down between the stones. If you do not want grass growing between the stones, put down a layer of landscape fabric below the stone dust and packed stone dust between flagstones.

How do you lock flagstone in place? ›

Polymeric sand, or “poly-sand” seemed great at first. As easy to install as regular sand, almost. You simply sweep the material into the flagstone (or other paver) joints, lightly hose down, then it solidifies. Once it dries and hardens, the sand stays in place.

Can I lay flagstone over grass? ›

Grass won't grow well between crowded stones. Not only do the roots struggle, but the summer sun heats up the flagstones, and, in turn, the flagstones heat up the surrounding soil. This dehydrates the grass roots. Keep stones at least 3 inches apart.

Is flagstone cheaper than concrete? ›

Flagstone will require more labor time and cost to install.

Generally, concrete pavers will cost anywhere from $3-$6 per square foot, while flagstone will run anywhere from $15-$20 per square foot.

Which is better flagstone or pavers? ›

In general, flagstone look great (color, texture, and design) and are natural stones, so they're as unique and unlimited as nature itself. Pavers, on the other hand, are cheaper, more durable and easier to replace. The final decision will be up to you.

How much space do you need between flagstone? ›

You don't want them too far apart so that it feels awkward to walk along your path. Make required adjustments and then begin adding the other stones at one end of the walkway. Position them around the larger stones in the middle to your liking, being sure that the gaps between each stone are around 1" or 2".

How do you keep flagstone from sinking? ›

Use a level to see that the bottom is flat and level. If you're using coarse sand, you may moisten it with a fine spray of water to help tamp it down and pack it tightly. This layer will keep the stone from sinking over a period of time.

How do you level a flagstone patio? ›

How to build a flagstone patio - A Helpful Guide - YouTube

How do you mortar a flagstone? ›

The ordinary way to make mortar is two parts cement, nine parts sand and one part hydrated lime; you'll need to mix these ingredients well before pouring in the water. Once they're all mixed, slowly pour in the water until the mixture is able to be shaped and stand up on its own.

How do I build a budget patio? ›

The cheapest way to construct a patio is to fill the space in with gravel or decomposed granite and add a modest amount of pavers or interlocking tiles to put below your outdoor furniture. If you do this yourself, it can be under $1 per sq. ft. Hiring someone to do it for you might double the cost.

What do you put under flagstone walkway? ›

Helpful Tips. Place a large piece of plywood (large enough to fit across the width of the walkway and to walk on) down at one end of the path and walk on it to further tamp down the stones. Pick up the plywood and repeat the process along the path until you get to the other end.

Does flagstone break easily? ›

Flagstone won't crack, and it won't shift position because of the changing temperatures. The stone is easy to maintain. You don't have to do anything to flagstone to keep it looking good except sweep it or spray it down. If any stains set in, such as from mold, you can remove them with a mix of bleach and water.

How many sq ft does a pallet of flagstone cover? ›

An average pallet covers between 210 to 560 square feet, but, just as with the coverage of flagstone priced by the ton, how much square footage you get depends on thickness and density.

Can you lay flagstone over concrete? ›

While traditionally flagstones are set in a bed of compacted sand and gravel over raw dirt, they can also be installed on top of an existing concrete surface.

What is the best base for flagstone walkway? ›

Concrete, aggregate, bark, gravel, and stones can be set directly on stable soil; paths made of of other materials need a base. Sand is a good choice, but it can wash out from under pavers and bricks, making them settle unevenly. To prevent washout in rainy areas, layer sand over a 2-inch gravel base.

What do you put under flagstone walkway? ›

Helpful Tips. Place a large piece of plywood (large enough to fit across the width of the walkway and to walk on) down at one end of the path and walk on it to further tamp down the stones. Pick up the plywood and repeat the process along the path until you get to the other end.

Can pea gravel be used as a base for flagstone? ›

You can use pea gravel between flagstones to inhibit weeds, and provide a comfortable walking surface between the larger stones. Pea gravel adds a subtle textural contrast and the same long-lasting strength and durability as flagstones.

What do you put under patio stones? ›

The pavers lie on a 5 1/2 -inch bed of sand and gravel. The bottom 4 inches is gravel to provide drainage. The top 1 1/2 inches is bedding sand that helps hold the pavers in place once they're compacted into it. Finer sand, sprinkled between the pavers, keeps them from shifting.

Videos

1. How to build a flagstone walkway part I
(Stefan Grunkemeier)
2. HOW TO LAY+GROUT FLAGSTONE SLABS |PRO GROUTING NATURAL STONE SAND JOINTS |MASONRY PATIO PAVERS
(CarlTheLandscapeGuy)
3. How to build a flagstone patio - A Helpful Guide
(Backyard Water Garden)
4. Installing a Flagstone Patio-DIY
(DIY Network)
5. The ultimate guide to Flagstone Patio building!
(Sierra Landscape Management LLC)
6. HOW TO LAY A FLAGSTONE PATIO: Using Gator Base Instead of Gravel
(REBEKAH HIGGS)

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