I used QUIKRETE® Mortar Repair – gray (No. 8620-09) with a standard caulking gun. The stuff is a sanded latex acrylic that sticks to brick, block, stone and concrete. The texture and color blends with the surrounding mortar. And the square applicator tip is designed to smooth mortar joints. Puncture the tube and apply it deep into the joint, and fill from back to front. The unique square applicator tip is designed to fit between the bricks and smooth-out the caulk as it’s being applied.
Mortar joints get damaged from bad, harsh weather, mostly water and temperature changes creating and contraction, and ice. Bricks can last a century, but mortar less than 25 years. Cleaning out decaying mortar, and tuckpointing and, repointing joints with the caulk is easy enough if you have patience and time.
Tuckpointing and repointing can’t fix cracking bricks, or wall cracks from a shifting foundation. Remove the bad mortar and clean the joints to a depth of ¼ inch to 1 inch. You can use a screw driver, hammer and chisel, wire brush, raker bar or an angle grinder with a masonry blade. Then clean the joint with a broom, leaf blower or even a little water.
Apply the mortar repair caulk.
Keep the applicator tip clean as well as your hands with a rag and water or you will have caulk staining everything. Be patient, and take your time. And clean the brick around the mortar line to create a clear line.
After a week, you can apply a sealer to the area, but it’s not really needed.