How To Repair Damaged Brick Work
Like many home repair tasks, damaged brickwork should be fixed sooner rather than later to prevent further damage. Replacing one or two bricks is something that most DIY enthusiasts can tackle, however if more than 4 bricks need replacing then get the professionals in, especially if it's a load-bearing wall. But if you fancy having a go yourself, here's how it's done.
Step 1: Remove the brick
The trick is to take the worn brick out without causing damage to the surrounding ones. So, rather than bashing away with a hammer and chisel, try drilling a series of holes in the mortar instead.
When you have gone all the way round, the brick will feel loose - now you can use your chisel to completely work it free and clear away the left over mortar. Remove any dust with a stiff brush, then wet the cleaned area with water to prevent the surrounding bricks from leeching moisture from the mortar.
Step 2: The replacement brick
Getting bricks that exactly match your wall is key to a successful repair. If your damaged brick is only marked on one side, you can simply turn it around and replace it. But if it's rotten throughout, shop around until you get an exact match. If your new brick isn't quite right, you can lighten or darken it. See "how to characterise bricks" for the know-how.
Lay a mortar bed along the bottom and sides of the hole to about 2 centimeters thick. Wet the replacement brick and 'butter' the top and sides. Now the fun bit, slide it into place on the wall. The mortar will ooze out around the edge, but keep tapping it in until it is flush with the other bricks. Use a trowel to add more mortar to the joint, packing it in to hold the brick in place.
Step 3: Finishing up
Scrape off any excess mortar from the face of the wall. Run a pointing tool, or length of rubber piping firmly along, compacting the joints to create a weather proof, concave finish.