#Concrete fire pit full
#Concrete fire pit crack

I dug about 8' down and used a stamper to flatten and compact the soil at the bottom of the hole. If you're building in cold climate, I recommend putting in footings that go beneath the frost line under each corner. Since I built the fire pit in southern California, I didn’t have to worry about putting in footing below the frost line. Place the frame in the desired location and mark about 6' around the outside perimeter. Make sure to put the L-brackets on the inside corners of the frame since the outside ones will be buried in concrete.

The inner frame is made from 2 panels that are 23' long and 2 panels that are 20' long. I used 2.5' deck screws and 15' long pieces of 2x4 to make the 4 large panels for the outer frame. I used 6' L-brackets to join the panels at the corners. If you do use a circular saw, I recommend using a speed square to make sure your cuts are nice and straight. I used a circular saw to cut them, but a compound miter saw would make this task a little easier. Each panel is made from 2 pieces of 2x4 and 2 pieces of 2圆. The outer frame will be made of 4 panels that are 43.5' long. RYOBI 10' Sliding Compound Miter Saw with Laser I used L-brackets to join the panels at the corners. I used 2x4s and 2圆s held together with 2.5' deck screws to make the panels for the formwork.

#Concrete fire pit crack

The lava rock is heat-resistant and won't crack or shatter.

#Concrete fire pit full

I used two 5 gallon buckets full of lava rock that I purchased from the masonry supply yard. I used about 7 bags of Quikrete 3/4' gravel for the foundation layer. This rebar frame will keep the different layers of concrete securely bonded to each other. Wire the horizontal pieces to the vertical pieces so that the horizontal pieces will be embedded in each layer of concrete. Make sure you drive the vertical pieces through the gravel and into the ground so that the ends are at least 3.5' below the top of the wood forms. Use 18' long pieces for the verticals and 36' long pieces for the horizontal pieces. I recommend using a combination of pre-cut 3/8' diameter rebar. I should've purchased 18' long sections for the verticals. I bought pre-cut rebar in 12' and 36' sections. I followed the directions that came on the mortar clay bag. I mixed my own mortar from a combination of Portland cement, mortar clay and sand. Fire bricks are heat-resistant and will protect the concrete from cracking. They aren't the prettiest looking, but after a few fires they will turn black from the soot. I used fire bricks from a local masonry supply yard. It’s great for making tables, pavers, stools, and lamps and is typically found in 80-pound bags at Home Depot, but 60-pound bags are also available.

This is the recommended concrete mix to use because of the high early strength and low price. QUIKRETE® 5000 Concrete Mix is a commercial-grade blend of stone or gravel, sand, and cement and is specially designed for higher early strength. If you're building a fire pit in a cold climate, I recommend putting a sonotube footing under each of the four corners. 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. 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. 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. Concrete fireplaces and fire pits should be constructed carefully. This isn't a difficult project, but it's time consuming and labor intensive. This modern concrete fire pit can be built over a single weekend and is a great centerpiece for outdoor entertaining.