Things You'll Need
Damaged mortar or brick can become saturated with moisture from your home's exterior or interior. During cold seasons, this water can freeze and expand, causing cracks in the brick. Over many winters, this process can cause the brick face to fall off. Brick that has begun to crumble in this way is referred to as "spalled." Unfortunately, spalled brick is impossible to repair without replacing. Once a brick has begun to crumble, it cannot be reassembled.
Drill holes in the mortar at all four corners of the spalled brick. The holes should be small enough to do this without touching or damaging the other bricks in the wall.
Tap in a masonry bolster between the brick and the mortar, on all four sides of the spalled brick. The mortar should start to crumble and fall out. Repeat this process with increasingly large bolsters to widen the hole around the spalled brick.
Remove the brick if it is loose enough. If it is not, continue to tap around the brick with a bolster until the brick will come free.
Line the sides of the hole with fresh mortar and allow it to sit for 10 minutes. Insert the new brick and insert more fresh mortar into the hole around the brick using a narrow tuck pointing trowel.
Determine the cause of the spalled brick before replacing it. Often spalled brick is caused by a leak or moisture problem. If you do not fix the source of the problem, you could find yourself replacing the spalled brick all over again in a few short years.
Brick made prior to 1930 were softer and more porous than today's bricks. This type of brick requires a softer, lime-based mortar. Have your mortar professionally tested before placing fresh mortar in your home, to determine what type of mortar is appropriate for your house.
To protect your eyes from flying mortar, wear safety goggles during this process.