Build Outdoor Fireplace With Cement Board

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.

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. 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. Use screws to attach metal lath which is a wire mesh over all of the exposed cement board. The metal lath will provide support for the stone that will be placed on top.

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. Nail gun nails drill screws chop saw shovel chimney cap protective gloves screwdriver masonry anchors or bits. 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. But on the metal surround use high heat adhesive to attach the cement boards.

On the ground and drywall use thinset and screws to attach the cement board. 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. We had a plan of attack.

I suggest 4 solid block for this purpose. 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. 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. Just remove the burner and lift out the tank when it needs to be refilled. Tap the sides with a hammer to release any bubbles that may be trapped in the concrete. Cut cement board to size using chop saw.

Using drill attach cement boards to frame with concrete screws. The metal lath will provide support for the stone that will be placed on top. 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.