Make a concrete firepit for winter evenings outdoors
With chilly evenings heading our way here's how to build a simple concrete firepit that will add a dash of style to an outdoor patio, while warming up cold nights in the garden.
The inspiration for this project came from an old metal fire bowl that was headed for the trash. Instead of throwing out they decided to reuse the metal bowl. By creating a square concrete frame and filling it with gravel and pebbles, the bowl was set in place and can be used to burn wood or charcoal.
You need a solid area for building the concrete firepit. Add a sand bed if you need to make a level area.
Make up a form for pouring the concrete. You can nail together pine or shutterply (cheap plywood) to make the form and will find this at your local Builders. You need to build an outer and inner frame and secure with stakes set on the outside of the form. Use two stakes per side. These will also secure the form to the ground and keep it from moving around. Use a spirit level to ensure the form is level on all sides.
Use a hammer to drive steel rebar into the form at the corners and at 20cm intervals along the sides. Make sure the rebar is securely in the ground and sits below the edge of the frame. Run lengths of rebar horizontally between the vertical rebar and tie these together with steel wire to make the reinforcing grid. For extra reinforcement, add chicken wire mesh. Cut pieces to fit inside the form and tie to the rebar grid with wire. Steel rebate and chicken wire can be found at your local Builders.
Pour concrete inside the frame. Find instructions here for quantities for mixing concrete. Use a wood batten to tamp down the concrete so all holes are filled; you don't want any air bubbles trapped inside the form. Smooth off the top with a wood trowel. Once the form is filled, tap with a rubber mallet while still wet. Leave to dry for 48 hours.
After 48 hours you can carefully remove the forms and use a steel trowel to clean up and smooth the outside.
To finish off, pieces of slate to fit the top of the frame and mortar in place and then add gravel about three quarters of the way full, so the top of the fire bowl will be flush with the top of the concrete frame. Add or remove gravel until the bowl is at the correct height.
Top up around the bowl with decorative pebbles so that only the top rim of the bowl is exposed.