What You'll Need
- tape ruler
- spray paint (for marking)
- handheld tamp
- modular retaining-wall units (often sold in kits that eliminate the need to cut units)
- gravel (1 cubic yard; road base material)
- coarse concrete sand (1 cubic yard)
- concrete adhesive
- pavers (optional)
* Before installing an open fire pit, check local codes and beware of any burning bans.
Site the pit on a flat area about 12 feet in diameter. Place the stake at the center of your desired circle (ours is 56 inches in diameter), tie the spray-paint can to a string attached to the stake, and mark a circle. Dig out the dirt within the circle to about 18 inches deep.
Fill the pit with 6 inches of gravel. Rake smooth and tamp after each load to make a solid base. Then spread a layer of course sand over the gravel, tamp, and check that it's level.
Use the stake, string, and paint to mark an inner circle guide for placing the first layer of retaining-wall units. Our inner circle is 38 inches in diameter.
Place the first row of retaining-wall units in a circle. Use the mallet to set them in the sand and gravel. Check that it's level from side to side and front to back after you place each unit.
Add the second row of retaining-wall units. Many products feature a groove on the bottom and a ridge on top, allowing the rows to interlock. Add the top row of blocks and glue in place with the concrete adhesive. Make sure the blocks are clean and dry before you apply the adhesive.
To surround the pit with pavers, first create a 6-inch gravel base topped with 1 inch of course concrete sand. Lay the pavers in the pattern of your choice. After the pavers are in place, install a plastic or aluminum-edge restraint. Sweep concrete sand into the joints until the joints are full. Compact the surface with a hand-compactor or rent a plate contractor.
Make sure a fire pit is installed away from potential fire hazards, such as wood decks, shrubbery, fuel tanks, or any structures.