A few damaged bricks can greatly impact the overall appearance of a brick wall. If you can find appropriately matched bricks, consider replacing them yourself. The cost is often minimal, and the impact such a repair can make on your yard can be significant.
Begin by using a masonry attachment on a power drill to score the face of the brick. This makes it easier to remove as well as ensuring that when you remove the brick the breaks are even.
Next, get a cold chisel and a hammer and carefully chip out the damaged pieces and as much of the surrounding mortar as possible around the damaged brick. Always work from the top down, row by row, to be able to remove as much of the damaged brick as possible as efficiently as possible. Use a wire brush to remove debris and dust as you go.
When all of the damaged brick has been removed, you can begin to replace the damaged area with new bricks. Make sure that you have purchased bricks that have the same fire rating and color as the existing brick. Mix the mortar with pigment as needed to match the surrounding mortar. Given the color difference between dry and wet mortar, you may want to do a test batch for color matching purposes.
Now wet the area where you will be replacing the damaged brick with water. This will help the mortar better adhere. Use a trowel to apply mortar about an 1″ thick on the bottom and sides of the hole where the damaged brick once was. Wet the replacement piece lightly, then apply mortar to the sides and the top. Press it into place so it fits with the existing rows. Continue these steps until you have finished filling the area that once contained the damaged brick.
Now check the mortar around the bricks. Make sure that the mortar is flush with the wall, if it is not press in a bit more mortar. Then, using your trowel, work the joints until they look the same as the surrounding joints. The type of mortar finish you will need will depend on your particular wall. Then allow the mortar to dry until the excess crumbles slightly, then brush it away.
Replacing damaged brick is an easy job so long as the bricks are not part of your house, the flue of your chimney, or a very tall wall. If you find damaged brick in those places, call a professional because of the safety issues at play. Damaged brick in a chimney flue can be particularly dangerous, so be sure to contact someone as soon as possible for problems of that nature.