Stack stone is ideal for do-it-yourself homeowners because the stones have raised ridges, or tongues, on top and grooves on the bottom that interlock for easy installation. Roman stack stones have rounded edges, giving them a cobblestone look that makes the wall appear older. They are solid concrete with tapered ends to achieve curves without gaps or having to cut the stones to fit. Alternate the tapers to make straight edges and stack the stones with the tapers facing the same direction to make circles. Fire pits are usually round, so Roman stack stone is the ideal building material.
Things You'll Need
- Measuring tape
- Garden hose, rope or spray paint
- Digging tools
- Crushed rock
- Hand tamper
- Concrete adhesive
- Roman stack coping units
Lay out one course of Roman stack stone with the tapered ends facing in to form a circle that will be the dimension of the fire pit. With Roman stack stone, it is much easier to use the natural dimensions based on the fit of the tapers than to try to make additional cuts to the stone to fit your own dimensions.
Measure the inside and outside circumference of the circle made by the first course of blocks, then measure the inside and outside radius.
Outline these dimensions at the fire pit site, using a garden hose, rope or spray paint.
Excavate the circle to a width of approximately 4 inches wider than the measurements and a depth of 4 to 6 inches plus half the height of the stone. Bury half of each stone for added stability and make sure the trench is level.
Spread a 4- to 6-inch layer of crushed rock or foundation base material in the trench. Compact it down 1 to 2 inches, using the hand tamper.
Pour in a 1-inch layer of sand and level it with a short screed. A piece of 1-by-4-inch lumber the width of the trench works well as a screed.
Lay the first course of Roman stack stones into the circle trench, with the tapered ends facing the inside of the circle. Check the blocks to make sure they are level. Pack more sand or remove sand from beneath the blocks to adjust high and low spots, as needed.
Fill in the trench on both sides of the blocks to ground level, using some of the excavated soil. Pack soil around the blocks so they are anchored firmly in the ground.
Lay the second course of stone with the vertical joints overlapping or centered on the stones in the previous course for additional stability. Apply a bead of concrete adhesive inside the groove, plus two more beads on the bottom of the stones. Place the stones carefully to line up the grooves with the tongues on the previous course of stones.
Lay one more course of stone or more courses to suit your height preferences. The final course should be laid with coping units, which are identical to Roman stack stones, but without the tongue on top.
How to Build a Dry Stack Fire Pit
Fire pits are are common features in backyards, gardens, porches and patios. Made of metal, rock and masonry block, fire pits provide...