How to Install A Flagstone Patio? Two Methods Explained

How to Install A Flagstone Patio? Two Methods Explained
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One of the most inviting places in any home is the patio.

The lighting scheme, the furniture, awnings, features, and décor all make that place your favorite spot around the house because of the natural beauty of the outdoors coupled with the comforts of a relaxing environment.

If you don’t have a patio and want to build one yourself, you can use flagstone pavers to create a gorgeous, welcoming patio in a fairly short amount of time.

If that’s your goal, we’ve got two types of flagstone patio tutorials, and some info you’ll want to consider before you get started.

Choosing Your Flagstone for the Patio

Choosing Your Flagstone for the PatioBefore you get started with the actual project of installing your flagstone patio, you’ll want to make sure you’ve chosen the right kind of flagstone for your needs and wants.

Flagstones come in either a fractured or cleft slab of various lengths, and will be two inches thick, or more, with random edge shapes.

The commonly used types of flagstones for patios include:

  • Redstone
  • Sandstone
  • Limestone
  • Granite
  • Bluestone
  • Slate

Flagstones will have irregular shapes, or come in cut stone, meaning they have a finished, straight edge and square corners.

Irregular flagstones are great for either casual free-form patios or formal geometric designs, while the cut stone is better for squared and straight shapes.

flagstone patioWhatever kind of flagstone you choose, just make sure it’s at least two-inches thick, or it’s likely to break in short order. And be sure to over-order by 5%, since some of the pavers will break before you’re finished installing the patio.

Larger stones will cover the area more quickly, but they will be harder to move, design, and cut, so keep that in mind as you decide on your stones as well.

If budget is an issue, remember that a ton of flagstone covers about 120 square feet, so you’ll need to go with whatever options fit your price range.

As you decide on your flagstone options, be sure to look for a variety of visuals to inspire your final patio design. Check out sites like Pinterest and do some Google searches for “flagstone patio images” if you’re feeling a little stuck on the exact shape and style of patio you want.

Also, don’t forget to check Pinterest for some awesome ideas.

Basic Ways to Install a Flagstone Patio

Basic Ways to Install a Flagstone PatioThere are a few different ways to install a flagstone patio. You can either use sand or mortar, as well as a few other options. We’ll focus, however, on these two choices, with a step-by-step tutorial for both.

Before you get started, thoroughly read the instructions and materials list to ensure you’re thoroughly prepared to make this awesome and simple sand method flagstone patio.

1. Determine the Size of Your New Patio

The size of the patio will determine the quantity of supplies you’ll need, so before you do anything else, you’ll want to survey the yard where the patio will be installed.

Do some measurements and determine how much space you’ve got to work with, and how much of it you want to turn into patio versus a grassy area or walkway lined with additional pavers of the same style or another for a decorative accent.

2. Gather Your Supplies

Go through the checklist before shopping and before pulling everything out on the day of your patio building project.

  • Crushed limestone or gravel
  • Builder’s sand
  • Edging
  • Flagstones, pavers, or bricks
  • Sledgehammer
  • Yardstick
  • Tamper
  • Shovel
  • Rake
  • Utility knife or saw
  • 10-inch metal spikes
  • Safety goggles
  • Protective gloves
  • Polymer sand – optional

3. Remove the Old Patio or Prepare the Area

Remove the Old Patio or Prepare the AreaIf you’ve got an old, run-down patio in place, this is when you’ll need the sledgehammer to demolish the old one. Make sure you put on your safety goggles and gloves.

This is a great opportunity to burn some calories and some frustration out, so if you or your spouse have had a rough week, let that sledgehammer fly with the destructive energy.

4. Excavate the for Drainage

To make sure you’ve got proper drainage for the patio, you’ll need to excavate the area where the patio will be with a depth of at least eight inches. The finished patio should be level with the surrounding area.

 To determine the exact depth you’ll need, add six inches – this will be four-inches of a compacted base plus two inches of sand – to the thickness of your pavers. 

So, if your pavers are three inches thick, for example, you’ll need to excavate nine inches total.

5. Add the Base and Tamp

Now, you’ll add your base material, which is the gravel or crushed limestone. Tamp the material down so that it’s compact. Be sure to fill the excavated area evenly, measuring all around the perimeter and throughout the center of the patio space to make sure it’s a fairly level base of four inches.

6. Add Sand for the Drainage

Using your rake, level a two-inch layer of builder’s sand into the patio space. The sand will help the patio drain properly and make it easier for you to position the pavers and make the patio level.

7. Install the Edging

Now, install the edging around the perimeter of the patio. Be sure to anchor it with the 10-inch metal spikes. Cut and bend the edging as necessary to fit properly.

8. Add the Pavers

Now, it’s time to lay out the flagstone patio pavers. Slide the individual pieces close together for a clean, sharp look, or leave larger gaps if you want some plant groundcover working its way through. Tamp the pavers gently with your mallet to secure them into the sand.

9. Fill the Spaces with Sand

Finally, you’ll use the builder’s sand or polymer sand to fill any gaps between the pavers. Sweep off excess sand until you fill the spaces.

Note: Polymer sand acts like mortar when it gets wet so it will keep the flagstone pavers more firmly in place than the traditional builder’s sand.

This also discourages weeds from creeping in and keeps the sand from washing over the pavers after rain.

Step-by-Step Instructions: Mortar Method

Step-by-Step Instructions: Mortar MethodCompletely read the instructions before shopping for supplies, to ensure you have everything you need.

Read them completely through a few times before beginning the project as well, just to make sure you have a firm grip on what you’re doing.

1. Determine the Patio Size

Before you get started, make sure you measure the space where the patio will be going and determine the final size you’d like the patio to be.

2. Gather Your Materials

After you’ve purchased the supplies according to the size patio you’re building, you’ll want to gather all the supplies together.

  • Small sledgehammer
  • Hammer
  • Brick set
  • Carpenter’s pencil
  • Shovel
  • Sponge
  • Mason’s trowel
  • Flagstone
  • Rubber mallet
  • Mortar
  • Height gauge
  • Mortar box
  • Mortar bag
  • 2x lumber
  • Burlap

3. Create Your Trial Run

Next, you’ll lay out the flagstones in your pattern in a dry run next to the site where the patio will go.

4. Mix the Mortar

Then, mix enough mortar together for about a 3×3-foot section, and then trowel a one-inch thickness on the slab where the patio will end up.

5. Place the Flagstones

Lift out the stones from the trial run and set them in the mortar in the same pattern you tested in the dry run. Set the larger stones first and use a height gauge to set them at a consistent height throughout the space.

Push the stones down – don’t slide them.

Fill the voids with the smaller stones, cutting the stones to fit as needed. Level the stones with the rubber mallet.

6. Cut the Stones

To cut the stones, mark a cut line on the pavers. You can freehand the lines or use an adjoining stone on top of the one you wish to cut.

Score the line with the brick set. Tap and move the brick set one bit at a time along the line.

Now, set the stone on another stone or a pipe and break the stone with a single blow.

Remove any excess stone along the cut line, shaping it with the mason’s hammer.

7. Level and Cure the Patio

Level and Cure the PatioNow, check that all the stones are level. Pull up any low stones, add mortar, and reset them. Tap down any high stones. If tapping won’t level them, lift them and scoop enough mortar out to make them level.

Clean off any mortar spills or overages with a wet broom before laying down the next section of stones. The mortar will dry before you finish building, so make sure to do this at every 3×3 section.

Once the whole patio has been laid and leveled, let it cure for three or four days.

8. Fill the Joints

After the patio has cured for at least three days, you’ll mix mortar in the mortar box, and fill the joints using a mortar bag or pointed trowel. If possible, use the mortar bag as it squeezes out the mortar directly into the joints and makes less mess.

  1. Clean up any spilled mortar immediately with a wet sponge.
  2. When the mortar holds a thumbprint, finish the joints with a striking tool.

Cover the surface with wet burlap – keep wetting the burlap throughout the time – or plastic, and let it cure for another three or four days before you remove the burlap and begin using your patio.

Creating Your Perfect Patio

Creating Your Perfect PatioYou can easily build a flagstone patio in a single day, whether using the sand method or the mortar method. Of the two, the sand method is quicker, but the mortar method requires less maintenance once it’s installed.

If you’re interested in other methods as well, you can check out the mulch method from the DIY network.

Whichever plan you choose, you can recruit your kids, spouse, neighbors, or friends to help out and make an enjoyable day of creating the ideal place for relaxing evenings for many years to come.


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