Fireplace Hearth Construction Basics

What You'll Need
Skill saw
Tape measure
Wood glue
Mortar trowel
Silicon-based tile adhesive
Caulk gun
Wood screws
Bricks, stone or tile
Mortar or grout
1/4 inch MDF, plywood or framing lumber
1/4 inch Cement board

The fireplace hearth is a central feature to any home, dating back to a time when family meals were prepared there. Nowadays, of course, it serves a different purpose, but it is no less important in terms of aesthetics. Fireplace hearths can be constructed from many different materials, each attractive in their own right. With a moderate amount of skill and work, you can retrofit your fireplace with a reconstructed hearth, augmenting your mantel in just a few steps.

Step 1: Decide which material to use

The first step is to decide which material you want to use for the hearth façade. Common materials are brick, stone or tile. Make your decision based on your tastes, but also on the interior design of the room and the look of the mantel.

Step 2: Frame or lay foundation

If you will be using bricks, you will want a relatively flat type so they do not protrude too much from the floor. Use the framing lumber to frame in a space to lay the brick. The lumber need not be much wider than the bricks themselves. Most code regulations require that the hearth extend 16 inches out from the front of the fireplace and 10 inches out from either side, so factor this in when you build the frame. Also consider the size of the brick. Unless you have the means to cut them, it is advisable that the size of hearth be such that the bricks fit perfectly without the need to cut.

If you are using stone slabs or tile, rather than a frame, use ¼ inch MDF or plywood to build the foundation. It too should extend 16 inches out and 10 inches to each side, and make sure you build to the exact size of the hearth, for it will lie permanently underneath. Secure the material to the floor with wood glue.

 Step 3: Arrange the brick or lay the cement board

If you are using brick, lay them within the frame, arranging them in the pattern of your choice. Don’t mortar just yet, though, but there should be at least ¼ inch of space between each brick, enough for the mortar.

Or, on top of the secure MDF or plywood, overlay ¼ inch cement board for a non-combustible layer to which the stone or tile will be glued. This should be the exact size of the bottom layer.

Step 4: Mix and apply mortar or set the tile

Mix the mortar and, with the trowel, apply it between each brick so it overflows at the top. Gently scrape away the remainder, and before it sets, manually position the bricks so they are evenly placed.

For tile or stone, arrange them in the desired pattern then, with the silicon adhesive in the caulking gun, affix each piece of stone or tile to the cement board, leaving 1/16th inch between each piece for the grout. Don’t forget the ½ inch sides. If you’re using stone, decorate the sides with smaller, attractive tiles.

Step 5: Grout between the stone or tile

After the tile is set, apply non-combustible grout between the pieces, making sure it is evenly coated throughout. Let the tile work sit until completely affixed.

After the mortar has cured, remove the frame. You can choose to decorate the sides of the brick with tile to add a nice touch or leave it as is. Your hearth is now a complete, uniquely decorated addition to your fireplace. Just add some matching fireplace hearth accessories and enjoy your surroundings.