Things You'll Need
Thin plywood sheets
Demolition hammer with chisel bit
A raised hearth in front of your fireplace may provide the protection you need from sparks or rolling logs, but in the process it cuts off a large area of your floor space and creates a visual barrier that may make the room appear smaller. Removing the raised hearth and replacing it with flat tiles gives you the fire protection you need while allowing you to keep the floor space clear.
Place the thin plywood sheets around the raised hearth over the surrounding floor, covering an area of about 5 feet in every direction. Tape the plywood sheets in place with masking tape to prevent them from moving. The sheets will protect the rest of the floor from damage during the hearth demolition.
Put on a pair of safety goggles, a particle mask and some earplugs.
Attach a chisel bit to a demolition hammer. Place the tip of the bit at a mortar line on the raised hearth. No matter the material forming the hearth, you'll need to go through the mortar, as this is likely the weakest point.
Turn on the hammer and break your way through the mortar lines of the hearth, clearing the spaces between the hearth's stone, brick or tile surface. After you clear the mortar from the joints, aim the chisel tip at the base of the hearth cover material and pry the stones, bricks or tile up from the hearth core by undercutting them. With the top layer of material removed, you can see what composes the rest of the raised hearth.
Continue to cut away the mortar surrounding each brick if the hearth is brick all the way to the subfloor. Pry up the bricks after removing the mortar by undercutting the brick to the next layer down. Continue to remove bricks layer by layer until you reach the base of the hearth, the concrete or wooden subfloor of the room.
Chisel through a solid concrete hearth with the demolition hammer if the removal of the surface material revealed a concrete core. Work from one end of the hearth to the other, breaking the concrete off in sections until you reach the subfloor under the hearth.
Haul off all of the debris from the raised hearth in a wheelbarrow. Brush off the subfloor with the bristle brush, and then vacuum up any debris remaining.
Measure the height of the new tiles. If you intend the new hearth to be level with your floor, use concrete to fill the space, minus the height of the tiles. Mix the concrete in a large bucket using a drill with a grout mixing bit, following the manufacturer's instructions. Screed the concrete level with a 2- by 4-inch board and then allow the concrete to cure overnight.
Mix a batch of thinset mortar in a bucket. Spread the thinset over the concrete in the hearth hole with a notched trowel, then run the notched edges over the thinset to raise ridges throughout the surface.
Set the tiles in place over the mortar. Use either the center of the fireplace as the centerline of the tiled surface, centering the first tile laid in alignment with the center of the fireplace, or use the center as the point for the joint between the first two tiles placed. Set the rest of the tiles in place from there, butting them tightly together to remove the need for grout. Cut the tiles for the ends of the surface, when you need a partial tile placed, using a tile cutter.
Place a carpenter's level over the tile surface to make certain the tiles are level with one another. Tap raised tiles deeper into the mortar with a rubber-headed mallet and raise low tiles higher by adding more mortar to the base of the tile. Allow the tiles to dry overnight and then remove the plywood and masking tape.