How to Build a Fire Pit

Start at the store, not the yard. Brad holds up a tumbled retaining wall block and talks through why the shape matters. Blocks with a slight wedge or trapezoid shape curve into a circle without gaps, which is exactly what you want for a round pit. Buy one extra course worth so you have spares. For a pit this size he uses about 30 blocks across three rows. Grab a matching cap block too if your line offers one.

Find a flat, open spot well away from the house, fence, and any low branches. Brad rings the area with loose marker stones to set the outer diameter, then works out where the inner wall will land. Once you like the size, score the grass along the line so you have a clear guide to dig to. Measure across a few directions to keep it round. A garden hose laid in a loop works great as a flexible template if you want to fine-tune the shape.

Now the sweaty part. Strip the sod inside your circle and dig down a few inches across the whole area. You want the bottom course of block to sit below grade so the wall locks into the ground and won't shift. Keep the floor of the hole as flat and level as you can as you go. Pile the dirt in a wheelbarrow or cart so you can move it out of the way. This is the step that makes everything after it easier, so don't rush it.

Water is the enemy of a fire pit that sits all winter. Brad digs a deeper pocket in the center, pours water in, and watches how fast it drains. If it sits, dig down further and pack in some loose gravel so rainwater has somewhere to go instead of pooling around your ring. This one small step keeps the pit from turning into a bowl of soup after a storm and helps the base stay solid over the years.

Pour paver base gravel into the pit to build a firm, flat pad for the first row of block. Spread it out, then drag a straight screed board across the top to pull it dead level. This is the single most important step for a wall that ends up even, so take your time and check it from a couple directions. A tamped, level base means every block after this sits right the first time and you won't be shimming later.

Set your first block on the base, then work your way around the circle placing each one snug against the last. Check every block with a level, front to back and side to side, and tap it down with a rubber mallet until it sits flush. The first course sets the tone for the whole build, so get it level and evenly spaced before you stack anything on top. If a block rocks, add or scrape a little gravel underneath.

Build up from there. Set the second row so each block bridges the seam below it, the same way bricks are laid. Staggering the joints locks the wall together and keeps it from splitting along a vertical line. Keep leveling as you go. Brad takes the pit up to about three courses, which is a comfortable height for sitting around. Run a bead of landscape adhesive under the top row to keep the cap blocks from getting knocked loose.

Home stretch. Drop the metal fire ring insert down inside your stone wall. The ring protects the block from direct heat and helps the pit last. Once it's seated, pour in a bag or two of lava rock to fill the bottom. The lava rock spreads heat, helps drainage, and gives the pit a finished look. Brush a border of pea gravel around the outside if you want, then you're done. Light a fire and enjoy the spot you just built.