• 6” layer of crushed rock
• Coarse sand to fill in over rock
• Undisturbed soil for a base
• Modular concrete retaining wall block with tapered sides
• Concrete adhesive between courses
• 1+ block stacked above grade for the walls and capstone

1. Get the concrete

   Modular concrete retaining wall blocks are perfect for a concrete fire pit liner. Their uniform thickness makes stacking easier, the tapered shapes easily form a circular ring, and they are widely available and affordable.
   
   Buy enough for the liner ring to extend at least a full block above the surrounding grade.
   
   The added visibility will increase safety, and help prevent pets and toddlers from accidental tumbling over the edge.
   
   

2. Trace the footing of the concrete fire pit 

   For circular shape stone fire pits, use a wood stake and rope to make a simple compass and use it to trace an outline on the ground.
   
   

3. Create the pit

   Dig out the pit area and check that the bottom of the hole is reasonably level, then fill it about 6 inches deep with gravel or crushed rock. 
   
   

4. Set the base

   Tamp the rock down firmly, add sand and repeat. Most of the sand will filter down to fill voids in the rock. Keep adding until you have a top layer of only sand about 1 inch thick.
   
   This will provide a good setting base for the ring of blocks and also will make it easier to scoop out ashes. 
   
   

5. Lay the first course

   Set the first course of concrete block into a complete ring to check the fit. Make adjustments as necessary, then use a rubber mallet to tamp each block firmly into the sand.
   
   

6. Complete the fire pit construction

   Check for level then add the remaining courses.
   
   Use dabs of mortar or concrete adhesive between courses for stability and to glue the walls and capstone into place.
   
   

7. Firepit grill

   Need a cooking grate? Contract with a local metalworking shop to weld one for you. While you're at it, see if they also can fabricate a cover for the pit to enclose it when it's not in use.

Outdoor Gas Fire Pit