How to Build a BBQ Pit on a Patio Slab

Draw a circle on the slab with chalk. Use a compass to get an accurate shape and size. Make a 3-foot diameter circle to form the inside of the pit, building around the exterior of it.

Combine the ready-mix mortar with water in a wheelbarrow according to directions. Use a garden hoe to stir the mix thoroughly to the consistency of thick mud.

Lay a 1/2-inch layer of mortar around the exterior of the circle. Make the width of this layer equal to the width of the bricks.

Set a layer of bricks around the circle with the long sides facing inward. Keep a 1-inch gap between the bricks at their closest points to allow for airflow underneath the fire in the center.

Apply a 1/2 inch layer of mortar over the top of the bricks with a trowel. Spread the mix evenly.

Set a layer of bricks over the mortar facing the same direction as the layer below it. Stagger the bricks so each brick bridges two bricks underneath it. Apply mortar to the finished layer as you did the preceding layer.

Continue the formation of the pit until it reaches high enough to hold your insert or grill.

Set a 4-inch layer of gravel at the bottom of the pit. This prevents the fire from scorching the patio and catches loose embers that fall down.

Set a pair of bricks on the gravel spaced evenly inside the pit. Set a grate from a grill onto the bricks. This is where you will build your fire.

Set a larger grate over the top of the pit. Ensure this grate rests firmly on the bricks. This is where the food will cook.