How to Apply Cement for Flagstone Patios

Prepare the Base

• 1

  Measure out the area where you want to put your patio, then mark it off using stakes and string to have a visual reference.

• 2

  Excavate the dirt down to a depth of at least five inches. This leaves four inches for a cement base for the patio and one inch for the flagstones. Dispose of the excavated dirt, since you don't need it.

• 3

  Line the edges of the trench with lumber that covers the sides so you can easily pull the wood out when the concrete is finished curing. Use 1-foot by 4-foot boards, cutting them with a saw if you need to shorten them for the proper fit.

• 4

  Mix concrete, combining one part cement with four parts sand. Add enough water to make a stiff mix. Pour this into the trench, spreading it with a trowel, until you have filled the trench. Level the concrete with a flat board, pushing the board across the wet concrete to remove any excess. Allow the concrete to dry for at least 24 hours before continuing.

• 5

  Pull out the wooden forms, since you no longer need them.

• 6

  Lay the flagstone over the patio so you get an idea of where all the stones go, leaving a one-inch gap between edges. This allows you to get everything right and trim the stone before you're setting it into the cement. To trim too-big stones, use a chisel. Draw a line where you want to cut, using the chisel. Next, tap the chisel at the line with a hammer. Move the chisel up and tap again. Turn the stone over and tap from the bottom. The stone should break after repeated tapping.

• 7

  Mix more cement, following the same proportions as described in Step 4.

• 8

  Remove two to three stones from the patio. Mist the patio with a spray bottle to wet it.

• 9

  Spread one inch of cement over the exposed area.

• 10

  Lay the stones back in place. Tap them with a rubber mallet to set them in the cement. Push more cement into the joints between adjacent stones to secure the patio.

• 11

  Work your way across the patio until you've set all the stones. Periodically, use a spirit level to make sure your stones are level so you have en even patio.

• 12

  Wipe any excess cement off the face of the stones, using a damp rag.

• 13

  Allow the cement to dry for 36 hours.