This modern concrete fire pit can be built over a single weekend and is a great centerpiece for outdoor entertaining. This isn’t a difficult project, but it’s time consuming and labor intensive. Concrete fireplaces and fire pits should be constructed carefully. When exposed directly to high amounts of heat, the moisture trapped inside concrete can expand and cause the concrete to crack and in extreme situations, explode. I lined the inside of the fire pit with fire brick and filled the bottom with lava rock to ensure that the majority of the heat didn’t come in direct contact with the concrete. I built this fire pit in southern California, so I didn’t have to worry about putting in footings that go below the frost line. If you’re building a fire pit in a cold climate, I recommend putting a sonotube footing under each of the four corners.