Charmaine Suarez Firepit February 19th, 2018 - 09:54:10
The reinforced concrete was poured to a depth of 100mm, allowing the firepit lining stones to protrude 100mm above it, with a slope of 1:100 away from the pit. Letting the concrete cure for a week, we then laid out random limestone pieces to gauge the best arrangement. Random stone comes in varying thicknesses and sizes and takes a great deal of patience to lay properly. You can simply start laying and choose matching pieces, filling in the many small gaps with small pieces but we prefer to shape the stones so that gaps are consistent and the small pieces are minimal. Once the stone was shaped and mortared down the gaps were grouted with mortar, coloured to match the stone. The final thing was sealing the limestone with a good quality stone sealant. And there is your party feature! When you light a fire and let it burn for a few hours the limestone patio begins to heat up and radiate to the surrounding seats making a very cosy spot on a cool autumn evening.
Seat distance from the firepit is critical. Too close and the fire will be too hot; too far away and the heat wont reach you. You can vary the distance with each seat but we found that for a pit 800mm in diameter the seats should be about 1m away from the pit. This allows people to walk in front of each other around the fire. Once the rock seats are in place the next job was to pour concrete around the pit and around the bottom of the seats so that the outside line of concrete joins all the stones about halfway. The back of the rocks protrudes out into what will become turf.
Its a bit tricky to get the heavy slabs in an exact circle with a consistent height but its best to prop them up and backfill with the gravel so that each stone is buried 150mm leaving a 450mm deep pit. The top of the granite should be 200mm above the surrounding ground level to allow for the concrete slab and paving. You could cut each stone lengthwise along one edge to make them fit flush with each other but it isnt necessary. The bottom of the pit was then paved to make shovelling out the ashes easier.
Procedure: First, we excavated a pit approximately 1metre (3 feet) in diameter and 800mm deep. The ground we were working on was very rocky so we used a backhoe and it was difficult to carve a smooth hole as you can see by the photos. Next we dug a drainage channel from the bottom of the hole to a lower point beyond the extent of the fire area. This was essential in this circumstance due to the heavy rainfall and the heavy soil. If your soil is porous it may not be necessary to provide drainage to the pit. In the channel we laid the plastic drainage pipe and covered it with gravel. Because we wanted to line the pit with the 600mm granite slabs we placed extra gravel in the bottom of the pit to set the stones on upright in a circle.