Broken Firebrick in the Fireplace

Prepare the Area

• Obviously, you don’t want to have a fire going when you’re trying to replace a damaged firebrick so make sure the bottom floor of the fireplace is completely cool and free of logs and soot. If replacing the brick takes precedence over cleaning the fireplace, a heavyweight canvas drop cloth placed over the fireplace’s floor gives you a clean and safe surface to work from. Take a close look and inspect the brick and the mortar around the firebrick; if any other bricks are cracked or adjoining joints are cracked or crumbling, now is the time to repair these areas as well to save you the hassle in the future.

Brush it Away

• Use a stiff wire brush -- metal wire works best -- to scour over the damaged brick and especially the mortared joint. This will remove smaller particles and debris and make excising and replacing the damaged brick easier. Allow all of the debris to fall. If the crumbles fall into the fireplace soot, clean up as much as you can; if the debris falls onto the drop cloth, simply sweep it up with a whisk broom and dispose of it properly.

Brick Removal

• Once the area is free of debris, use a small hammer and a brick chisel to chip away at any mortar that’s holding the brick in place. Use only small strikes: You don’t want to damage any surrounding joints or bricks that are undamaged. Once the brick is loose, insert the edge of the chisel into the mortar slot and pry the brick free. Brush out the hole until it’s smooth and ready for the new brick. If there are other bricks to fix, remove them accordingly.

Brick Replacement

• Prep the mortar according to the package directions. Use a small masonry trowel to smooth wet mortar into the top and bottom of the slot then slide the new firebrick into place. Push the brick in and scrape away any excess mortar that oozes out from the joint. If other bricks need to be repaired, do the same to replace them. Allow several hours for the mortar to cure before firing up the fireplace.