How to Repair Masonry Surfaces
Over the course of your masonry surface's lifetime, you'll likely need to make a few basic repairs. This tutorial shows you how to repair cracks, flakes, holes, and more.
No exterior material is perfect. Masonry surfaces, for example, suffer some of the same categorical damage as other surfaces. They often display cracks or damages that require patching.
Patching damaged masonry can prove more difficult than repairing wood siding because even the best masonry repairs are visible, if only slightly. Although it's almost impossible to match the texture and color, getting a tight seal between the patch and the original surface is what really matters. Cracks and holes in stucco let water into the walls and will cause problems far worse than a mismatched patch.
When pigmenting a stucco patch, take the time to experiment with pigment proportions until you find a tint that matches the existing stucco when the patch dries.
Make necessary repairs to the underlying structure before you begin. Plan on building up your repair in layers over several days, allowing the patch to cure between applications. Thick applications will crack.
While the exact method varies with the masonry material, most repairs can be made in a few days. Our tutorial will help you mend mortar joints, concrete block, stucco, and more.
What You Need
- Raking tool
- Patching compound
- Masonry jointing tool
- Caulking gun
- Wire brush
How to Repair Masonry Mortar Joints
Flaking brick doesn't necessarily indicate a structural deficiency but does pose an aesthetic problem. Once flaking begins, it is almost certain to continue, even if you paint the brick. The best solution is to apply a skimcoat of mortar over the entire surface. Let it cure, then paint.
If it's just the mortar joints that show serious deterioration, rake out the loose mortar with a raking tool, remove the dust, and tuckpoint them.
Small cracks can be enlarged and filled with a masonry-repair patching compound. Whatever kind of repair you make, be sure to smooth the joints with a masonry jointing tool so the contours of the repaired joints match those of the old.
How to Repair Narrow Cracks in Concrete Block
Narrow cracks in concrete block (less than 1/4 inch wide) can be filled with caulking made specifically for this purpose or painted with an elastomeric wall covering. Both products expand and contract with the block, effectively bridging the crack, and both can be painted.
How to Repair Wide Cracks in Concrete Block
Wider cracks in concrete block should be keyed (made wider at the bottom of the crack than at the surface) with a cold chisel. This helps them hold the patching mortar more effectively. Remove residual dust with a brush or vacuum.
How to Patch Concrete Block
To patch a repaired area, mist it lightly with water, using a spray mister, and fill the recess with concrete patching mortar. Let the mortar dry thoroughly before painting the repaired area.
How to Repair Stucco
Step 1: Clean the Area
Clean out the damaged area with a wire brush, removing any loose stucco pieces. Blow the dust out with compressed air.
Step 2: Apply Stucco
Using a pointed trowel, narrow putty knife, or margin trowel, apply a thin coat of stucco patch and let it dry. Apply two more layers in the same fashion until the patch is level with the surrounding area. Do not let this coat dry before going to the next step.
Step 3: Roughen for Texture
Roughen the final coat of stucco patch until its texture matches that of the surrounding stucco. Add isolated clumps of patching material to increase the roughness of the texture.