Build Outdoor Fireplace With Cement Board

Using drill attach cement boards to frame with concrete screws.

Build outdoor fireplace with cement board.

Once your concrete footing has cured for 24 hrs or more you will need to build a level base on which to construct your firebox. Move the board back and forth as you slide it across the concrete adding more concrete to fill in any gaps around the edges. But on the metal surround use high heat adhesive to attach the cement boards. Cut cement board to size using chop saw.

The metal lath will provide support for the stone that will be placed on top. The concrete also needs steel reinforcement. To build an outdoor fireplace make a detailed plan of what the fireplace will be for where it will go and what will go around it. Tap the sides with a hammer to release any bubbles that may be trapped in the concrete.

Add cement board to the entire area you ll be tiling for us that means the floor and all 4 sides of the fireplace leaving room for wood mantle. For smaller areas of frame use chop saw to cut cement boards to size. You will want a minimum 4 thick up to 8 thick reinforced concrete pad. Just remove the burner and lift out the tank when it needs to be refilled.

The metal lath will provide support for the stone that will be placed on top. The door provides access to the burner controls. Next you will build your firebox to whatever size you have chosen using firebrick and refractory cement from your local masonry supply. Run a long flat board or concrete screed across the top of the concrete laying it on the board edges to keep the board level.

I suggest 4 solid block for this purpose. This outdoor fireplace looks like a solid concrete cube but this hollow box holds a standard propane tank and regulator the same components that fuel a typical gas grill. On the ground and drywall use thinset and screws to attach the cement board. Use screws to attach metal lath which is a wire mesh over all of the exposed cement board.

If you are building on a pre existing concrete pad or one much larger than your fireplace footprint be sure to form or cut expansion joints around the fireplace. There s a secret inside this outdoor fireplace. Once you know what you want to build lay a concrete foundation put a layer of cinder blocks over that then build the firebox and chimney out of firebrick and use a jointer and brush to remove bubbles from the mortar.