Repointing brick walls gives you an opportunity to remove crumbling mortar and prevent water damage by making necessary repairs on the wall. While repointing the exterior of a historical home should best be left to the professionals, repointing freestanding brick fences or other walls is a good project for a careful homeowner. Keep in mind that this project requires the use of a chisel, so be sure you are comfortable with this tool before starting the project.
Before beginning, keep in mind that different mortars are appropriate for different types of brick walls. Historical brick is softer than modern brick, and will react poorly with modern mortar. Adding modern mortar to the wall could cause cracking. Instead, use a traditional mixture of lime and sand to create a mortar that will not damage the brick wall.
Step 1: Remove the crumbling mortar between the bricks with a flat head screwdriver or chisel. Only remove the mortar that is not firmly attached to the brick: do not attempt to chip away the mortar at this point.
Step 2: Remove any cracked areas of mortar using a cold chisel and hammer. Make sure in any areas you want to repair that at least an inch of mortar is removed from all sides of the brick.
Step 3: Clean each mortar joint with a wire brush. This will ensure that any debris is removed from in between the bricks and bits of crumbling mortar you may have missed are promptly removed.
Step 4: Mix the mortar you intend to use for repointing the brick. Pay particular attention to the ratio of water to mortar mix: too much water can cause the mortar to crumble over time.
Step 5: Fill a mortar bag with your mixed mortar.
TIP: A mortar bag looks like the bags used to hold frosting for cake decorating. Most home improvement centers carry this tool.
Step 6: Pipe mortar into the cleaned joints between the brick wall using the mortar bag. Fill the joint completely before continuing to the next section.
Step 7: Use a small trowel to shape the mortar joints so they match the original joints in the wall. Try to avoid getting any mortar on the face of the brick: wipe any mortar from the face of the brick with a sponge immediately to prevent staining.