The outdoor fire pit has become a really popular backyard feature for many homeowners. And it provides a great centerpiece for outdoor get togethers. Many times a basic one is all a backyard needs, and we’ll tell you how to build a simple fire pit. It is fairly easy to build and could be a weekend project if you have a layout plan and the construction materials on hand.
Fire pits are best located on level ground for ease of construction and to create an enjoyable seating area around the fire pit. They also should be located safely away from nearby structures.
This fire pit measures about 38 ¾” square, outside to outside. It was constructed with concrete block (CMU), concrete pavers, gravel, and construction adhesive.
Before beginning a fire pit project, check with your local building department for safety issues and to comply with your local code.
Construction materials used to build this fire pit:
- 16 – 2 courses (8 for each course) of 4” x 8” x 16” solid concrete blocks (CMU)
- 20 – 5 ½” x 6 3/4” concrete pavers (for capping)
- to fit – 4” x 8” concrete pavers (for side veneer); some cutting may be needed
- Coarse gravel – for the 4” base, the outside of the CMU wall below grade, and the inner pit; the gravel also allows for water drainage
- high quality construction adhesive
How to Build This Fire Pit
The inside opening of the fire pit measures 28” square. The total excavated area was 44″ square to include the CMU wall and 4″ of coarse gravel around the perimeter of the wall. The depth of the excavation was 15”. About 4” of gravel was placed on the bottom of the entire excavated area. The CMU wall was built first, and then 4″ of gravel was placed along the outside of the wall, leaving the gravel about 3″ down from the top of the excavation for soil and/or lawn cover.
The first course of CMU was installed on top of the 4″ of gravel applying a high quality construction adhesive to the vertical joints in a tight zigzag pattern. Use a level to make sure the gravel and concrete block are level. The ends of the CMU overlap at the corners (See sketch below). The second course was installed and connected to the first course by applying the adhesive in between the courses and to the vertical joints in the same zigzag pattern. Avoid getting the adhesive along the edges of the CMU that will be closest to the fire.
About 3″ of the second CMU course was below grade on this fire pit. The finished height of this fire pit is about 6 1/2″ above grade (the lawn). The inside of the fire pit has a depth of 9 1/2″. To create a pit with more height, make the excavation less deep, but the first course of CMU’s should be completely below grade. The paver sizes used for the side veneer should be considered if adjusting the height.
When installing the second course, stagger the joints in relation to the first course to provide for a more stable structure. (See sketch above)
Concrete pavers were used to give the structure a decorative finished appearance. The CMU courses were capped with 5 ½” x 6 3/4” concrete pavers (see photo below), installed flush with the inside wall of the fire pit. The 4” x 8” concrete pavers were used in a running bond on the outside of the CMU wall as a decorative veneer. All the pavers were installed with the same construction adhesive.
After the fire pit is built, add enough gravel inside the fire pit to cover only the first CMU course. The finished depth of the inside of this pit is about 9 1/2″.
Fire pits built with concrete materials can be damaged and deteriorate over time when in direct contact with the heat of the fire. These materials can be protected by using a heavy duty metal insert.