Build an In-Ground Fire Pit
GATHER AROUND AS PRO BRICKLAYER DOUG MONTZKA SHARES HIS TIPS FOR BUILDING A LASTING OUTDOOR GATHERING SPOT
PLAN AHEAD
This project needs to be spread out over a few days. First, you’ll have to pour the footing and give it time to set. Then you’ll have to mortar the bricks into place.
Before digging out the space for your fire pit, call your utility companies (dial 811; for more info, go to to check the location of buried utility lines.
Also check the fire pit code in your area. Most require a fire pit to be 25 ft. away from any structures and overhanging trees. And think about how the prevailing winds affect your space.
1 MARK OUT THE FIRE PIT
First, choose a spot in your yard for the fire pit base. A 3-ft.-dia. pit creates enough room for a good fire, yet keeps everyone close enough to chat (and complies with most codes).
To make your own forms, rip a 4 x 8-ft. sheet of 1/8-in. hardboard into four 8-in.-wide strips. Carefully bend and screw two strips together to create a 36-in.dia. circle, and use the other two to make a 48-in.-dia. circle. Set the larger form in position and spray paint around it.
2 DIG AND LEVEL THE HOLE
Following the painted guide, shovel out the soil to a depth of 8 in. for your fire pit base. Do not disturb the underlying soil.
Check the bottom of the hole with a level and remove any high spots by scraping off soil rather than digging. This leaves the underlying soil intact.
Compact the soil with a hand tamper or a 4×4 post.
3 STAKE THE FORMS
A concrete footing will create a stable base for the pit walls and keep the sides of your pit from cracking as the ground moves over time.
Stake the forms and mix up ten 80-lb. bags of concrete mix per manufacturer directions.
If you’re using hardboard forms, stake them so they’re nice and round.
If the forms aren’t quite level, raise one end and drive a screw through the stake.
4 ADD THE REBAR
Bend the two rebar lengths to form a 42-in.-dia. circle. Bind the overlapping ends with wire to form a sturdy ring.
Fill the forms halfway, then press the ring into the concrete for strength. Make sure it doesn’t touch the sides of the forms.
5 FINISH THE FOOTING
Shovel in the remaining concrete until the forms are filled to the top and then tap the forms gently with a sledgehammer until the concrete mix is level.
Recheck the level, hammering the forms down if necessary, and smooth the top of the footing.
Let the concrete completely set up overnight. Remove the forms the next day.
6 DRY-SET THE FIREBRICK LINER
Regular clay brick can crack at high temperatures, so we’re using firebrick (also called refractory brick) to line the inside of the fire pit walls. You will need 25 firebricks for a 3-ft.-dia. pit.
Because firebrick is so dense, it’s tougher to split than regular brick. “Soldiering” the brick (standing it on end) minimizes splitting and lets you easily accommodate the pit’s curve.
For this project, you’ll only need to split four firebricks, which you’ll place across from one another around the pit to create draw holes for oxygen for your fire (see Step 8).
Dry-set the firebricks in place on top of the footing. Space out the bricks so that you won’t have to cut the last brick to fit.
Mark the position of every brick on the footing.