How to Lay a Flagstone Patio

Flagstone Patio

Flagstone Patio

Do you like puzzles? Then you’ll love putting together a flagstone patio.

Before you start, take care to protect yourself. Flagstone is heavy so wear a back brace, gloves and goggles.

Pick a level spot. If you start with a level area it’ll be easier to make sure the finished patio will be level.

Measure, measure, measure. Measure and string out the sides and stake the sides of the patio. Check to make sure you have a perfect rectangle. The two diagonals should be of equal length.

Dig out to a depth of 4-6 inches. With a spade (a flat shovel meant for cutting straight down) cut through the sod, into the soil. Do this completely around the perimeter of the rectangle you just made. Now with a digging shovel, remove all the sod, soil and rocks to a depth of 4-6 inches.

Level. Set a scrap plank down on the ground so that it runs the length of the patio on the left hand side. Put a carpenter’s level on the plank and check to see if it’s level. It probably won’t be exactly level but it shouldn’t be hard to correct it. Scrape away dirt on one end or the other to make it level. Repeat the process on the other side of the rectangle and then in the middle. Follow the same process for the other two sides.

Moisten the soil in the dug-up area with a garden hose and tamp it with a tamping tool. Put down landscape fabric over the base that you just made for your flagstone patio. This will prevent possible weeds later.

Create a Form. Now that you’ve got a level base, you’re ready to frame in the rectangle with a form made of four 2x4s nailed together to enclose the area. The idea is that the form acts as a mold to contain the 2” layer of sand that you are going to apply. Excavate around the perimeter another 1.5” x 1.5” deep to accommodate the 2×4. You want to have 2” of the form sticking up so the sand will be contained within the form.

Shovel 2” of Sand over the landscape fabric. Cut a piece of 2×4 to a length of 8’2” to use as a screed. Starting at one end of the rectangle you’ll slide the screed across the full length of the sand. Sliding the screed along the top of your form will level the sand. Excess sand will be redistributed to low areas and you’ll have an even surface when you’re done. Remove sand if you’re having a tough time moving the screed. Tamp the sand with a tamping tool.

Lay the flagstone. After finishing the sand the patio base sits 2” down into the ground. Coincidentally the flagstone you’ll be using is 2” thick so it will fit perfectly. Begin in a corner and place the stone pieces in the sand base like pieces in a puzzle keeping the gaps between the stones as small as you can.

Tamp the stones with a rubber mallet. Keep checking to make sure everything’s level as you work. If a flagstone is too low, take it out and put more sand beneath it. Do the reverse if it’s too high.

Cut stones to fit. Using a pencil mark where the cut needs to be made. While wearing your safety goggles score a line with a brick set and mini-sledgehammer. Repeat on the opposite face and the sides. This process will create a perforation so the flagstone can break where you want it. Place the scored stone on a piece of wood and strike it along the score using a mini-sledgehammer. The stone should split. If it doesn’t, repeat the scoring process going deeper to make it easier to break. Now you’ve got smaller pieces you can use elsewhere on the patio.

Sweep sand between the flagstones. Now that all the stones are in place you can dump more sand on the patio. Sweep the sand into the cracks between the stones.

Remove the 2×4 form and fill in the hole left behind with sand and tamp it firmly using the end of a scrap 2×4. Or you could use some stone to frame the patio for a different effect.