Firepits add a lot of ambiance to a patio or the backyard, but their construction doesn’t have to break the bank. The key factor is to build safely by choosing one of three materials (especially of using pavers or retaining wall stone): a fire bowl, a liner, or fire brick.
Although fire bricks can be used to protect the inside and bottom of the pit to insulate the decorative blocks, the preparation takes longer and costs more. For a quick, easy, and cost effective install, the liner or bowl work best.
1. Retaining wall blocks or pavers
2. Fire pit liner or fire bowl
4. Hand tamper
5. Rubber mallet
8. 3/4 inch gravel
9. Leveling sand
10. Construction adhesive
You may want to check with your county’s building code, but the standard recommendation is that a fire pit should be about ten feet away from houses and trees. Budget stones are easy to install and are affordable. However, they are not graded for fire. This can be offset and made safe by a buffer of metal and gravel.
Because retaining wall blocks are porous and hold on to moisture, they may burst in extremes of heat or temperature change. This is less likely with paver stones. When filling the pit with stone also avoid river rock, since it is known to explode with vigor when heated. Stick to granite or lava rock.
Liners are hollow metal tubes that fit over the stones, and the bottom of the pit is filled with gravel. A fire bowl, on the other hand, holds the fire above the ground and away from the fire pit walls, providing an adequate buffer.
A Matter of Shape
Decide whether you want a square or circular construction, and be sure the size will fit the liner or fire bowl size desired. Trapezoidal pieces are for round pits, but both types of blocks are designed to fit together in a stack 2-4 tiers high. There are a number of kits available that come with the correct number of pieces to put a pit together without having to buy separate components.
Backyard Ground Preparation
Lay out the base stones and mark it with paint, or use a shovel to start the circle. Removed the stones and dig about seven inches down. Keep the soil and turf on a tarp for filling in any unsightly gaps after building is complete.
Pack the dirt in the hole well. Use a level and piece of wood to check that everything is even. A hand tamper is not necessary but makes the job much easier. Fill the hole to a depth of 5 inches with gravel such as Quikrete. Wet and tamp down.
Check leveling again. Set down a layer of leveling sand and rake it over the surface.
Build the Wall
Lay down the first layer of wall. If the blocks don’t line up or are tilted out of level, use sand pushed underneath to adjust. A gentle rap with a rubber mallet can help get a stubborn block to sit properly.
Stagger the seams on the blocks just like with brick. Don’t secure the blocks with adhesive yet. Stack first and be sure the fire bowl and liner fit properly. If not, make adjustments.
Some retaining wall stones have a lip that prevents them from lining up for a fire pit construction. Gently tap it off with a hammer so they fit even and tight on top of each other. Pavers do not have the lip issue. It is not advised to build higher than four tiers.
Use the liner and fire bowl as a guide. Make sure they sit properly on the final course. Once you are satisfied with the placement and design configurations, use construction adhesive to secure the stones.
If there is a gap between the liner and the gravel, fill in with more 3/4 inch gravel or lava stone so that it reaches to the base of the liner with no space. This is a safety measure and will protect the blocks from heat. Fewer stones can be used for the bowl but are necessary to provide adequate drainage to keep the pit from becoming a pond.
If there are any patches left around the dug area, fill in with the reserved soil and turf.
The set up for a patio construction is similar, however, the pit can be built directly on top of the pavers. Take extra care to line up the stones with the insert or fire bowl, using them as a guide for size and placement. Secure the first course with adhesive directly on the patio. Continue assembly the same as for a ground pit.
Once constructed, fill the bottom of the pit with lava stone or granite gravel as before to provide a buffer and drainage.