How to Repair Mortar in a Brick Wall

Whisk away all the crumbly debris with a stiff-bristled brush, then check that the blade of your tuck-pointing trowel will fit into the joint. If the blade is too wide, grind it down with an abrasive wheel. Mist the wall with water until the brick is thoroughly damp and starts to drip; this is a critical step because dry materials will suck the moisture out of the new mortar and prevent it from curing properly. Wait until the next day before filling the joints.