How to Build a Fire Pit. Information for home design and remodeling.
Although sophisticated fire pit designs can include elaborate features such as gas lines and built-in seating, simpler versions that burn wood or charcoal give plenty of dramatic punch to a backyard.
Building a backyard fire pit is easy for the amateur, requires no special tools, and is relatively inexpensive (about $600).
For a fire pit like the one we built, allow roughly four hours to dig the pit and between eight hours and a full weekend to install the retaining wall and surrounding pavers. Although you should apply concrete adhesive to secure the top layer of retaining wall units, you don't need to mess with mortar.
In choosing a site for the fire pit, look for or create a flat area at least 10 - 12 feet in diameter. Ideally, you should prep the area surrounding the pit (not within it) with a layer of decomposed granite, pavers, or concrete to create a nonflammable surface.
Small, modular retaining wall units, used to create the fire pit enclosure, are available at most builder supply stores for $1- $2 each. A variety of colors, shapes, and sizes of units provides plenty of room to use your imagination as you select the color and style best suited to your yard.
MATERIALS Retaining wall units (Use a kit, or get a supplier's estimate of the number needed.) Coarse concrete sand (1 cubic yard) Gravel (Road base material is best; pieces vary in size up to 3/4 inch in diameter.) (1 cubic yard) Concrete adhesive
TOOLS Shovel Rake Handheld tamp (To create a homemade tamp, wire a 12x12-inch piece of plywood to a sledgehammer.) Level String Stake Tape measure Marking paint Wheelbarrow Mallet Wet saw or circular saw (to cut pavers, as needed) Safety Glasses Hand compactor or rented plate compactor
Cut a piece of string the same length as the radius of your fire pit. Tie one end of the string to a stake in the center of the fire pit location, and tie the other end of the string to an upside-down can of marking paint. Draw a circle with the paint to identify the perimeter of the pit. For this project, we used a circle with a 28-inch radius (for a 56-inch-diameter pit).
Dig out sod and dirt within the marked circle. Make the pit approximately 18 inches deep.
Pour 6 inches of gravel into the pit, raking the gravel smooth after each load to ensure a solid base. Rake the top layer flat, then tamp it down. (Many installers spread a thin layer of sand over the gravel but some suppliers say this is unnecessary.)
Using the string mechanism from Step 1, mark an inner radius as a guideline for placing the first layer of retaining wall units. (We used a 19-inch inner radius.)
Place the first row of retaining wall units in a complete circle, securing them into the gravel base with a mallet. The retaining wall units in the kit we used were contoured to fit around the circle with no cutting. Use a level to make sure the units are level from side to side and front to back.
Add the second row of retaining wall units. The retaining wall units for our project each featured a groove on the bottom side and a ridge on the top, allowing the rows to interlock. Add the coping, or top, row. Our coping units had grooves on their undersides but no ridges on top. Make sure the units are clean and dry, then use a concrete adhesive to glue the coping row into place.
To surround the pit with pavers, create a 4- to 6-inch gravel base topped with 1 inch of coarse concrete sand. Lay the pavers in the pattern of your choice. Some patterns let the bricks align on the edges, while others create a staggered layout with every other brick sticking out. Creating a smooth edge is a more complicated process because it requires you to cut bricks as necessary. After the pavers are in place, install a plastic or aluminum edge-restraint around the edges of the pavers to keep them from moving. Sweep concrete sand into the joints until joints are full; compact the surface of the pavers with a hand compactor or rented plate compactor.