- 1). Dig a rectangular pit that's at least eight inches deep and is 40 by 56 inches around. Measure and clear the required area first. Level the area after digging with a hand tamp.
- 2). Lay a bed of gravel that is two inches deep within the pit. Spread a layer of mortar around the area over the gravel that extends two inches inward from the edges of the pit. Use dry mortar mixed with water and spread it with a trowel.
- 3). Smooth down the area, using the trowel when the mortar is wet. Place flat cinder blocks along the edges of the pit, making sure each block is level. Fill up the rest of the hole between the blocks with dirt after the mortar is dry.
- 4). Spread and smooth another layer of mortar over the cinder blocks to lay the first layer of bricks. Lay each brick horizontally across the pit edges, applying mortar to the brick edges, and surround the pit's perimeter. Add two more rows of bricks so you have a layer of bricks three wide around the perimeter.
- 5). Add another layer of bricks on top of the first, applying another layer of mortar on top of the first layer first. Use the "alternating pattern" for the second layer, meaning the ends of two bricks on one layer meet up with the middle of one brick on the other layer.
- 6). Insert metal braces within the next layer of mortar you apply over the second layer of bricks. The braces will be along the inner edge of the brick layer, pointing toward the pit's center. Add a final layer of bricks on top of the second layer.
- 7). Wait for everything to dry overnight. Place the bars of a metal grill within the center of the pit, balancing it on the metal braces.