If your home’s chimney or exterior brick walls are showing signs of deterioration, it’s probably time to repoint the mortar between bricks. While this is a job often best left to professionals, and especially for severe cracks, chips, and other such damage, a homeowner might make minor and simple repairs on their own.
To repoint brick mortar, you’ll need an angle grinder, a hammer and chisel, some muriatic acid and a glass jar, a thick trowel, and enough sand and lime to mix together for new mortar. You’ll also need thick work gloves, safety glasses, and a breathing apparatus as well as a well-ventilated, safe work environment!
Using the angle grinder or hammer and chisel, remove a chunk of mortar and place it in your glass jar along with enough muriatic acid to cover that chunk. Let the acid etch away at the mortar until you see the original sand color. That original color tells you how much sand to use for new mortar so that your patching material matches the current mortar!
Using your angle grinder or hammer and chisel, remove the remaining damaged mortar, using caution that you don’t damage nearby brick. Once finished, remove all remaining dust and dirt; use a stiff-bristled outdoor broom or even a leaf blower if needed.
Next, mix your new mortar. Use one part lime to three parts sand, adjusting the amount of sand used until your new mortar matches the color of the existing mortar, as exposed by the muriatic acid.
Wet down the current brick so that it doesn’t pull water away from your new mortar and so the new mortar stays a proper consistency as it dries and hardens. Use a trowel and push new mortar into the end of the gaps where you’ve removed damaged mortar.
Wait several hours for the new mortar to set and then use a stiff brush or rag to remove excess mortar from the face of the brick wall or chimney. Use caution that you don’t pull away fresh mortar from the repointed joints.
If these steps don’t create fresh mortar that sticks to brick and the current mortar, or you can’t seem to create a matching mixture, consider calling a professional. He or she will ensure that your new mortar is mixed properly and coordinates well with existing brick and other materials.