How to Install A Flagstone Patio: Two Methods

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.

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

If 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.

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.

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.

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.

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.

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.

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.

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.

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

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

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.

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.

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.

Now, 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.

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.

Clean up any spilled mortar immediately with a wet sponge.

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.