How to Repair Stucco Cracks and Holes
On a wood-sheathed stucco wall, the sheathing is covered with roofing felt, then wire lath is nailed over the felt. Two or three layers of stucco are applied over the lath. On a masonry wall, stucco is typically applied directly with no lath.
Before patching a small area, press hard with your palm against the surrounding wall. Wherever you find sponginess, the stucco has disengaged from the wall and should be removed and replaced.
Getting a stucco patch to blend with its surroundings is more difficult than it may first appear. However, by experimenting with various tools, you can likely discover how to apply a texture that comes close.
What You Need
Caulking gun
Hammer
Cold chisel
wire brush
Lineman's pliers
Tin snips
Putty knife
Old can opener
Detail scraper
Masonry brush
Magnesium float or flat trowel
Scarifying tool
Paint roller
Wheelbarrow or trough
Masonry hoe,
Ladder or scaffolding
Stucco caulk or exterior caulk
Stucco patch
Stucco mix (basecoat and finish)
Roofing felt
Stucco lath
Roofing nails
What if you Need to Texture Your Patch?
Start with a basically smooth wall that is at the same thickness as the surrounding surfaces. Use a masonry brush or whisk broom to etch swirls, straight lines, or a pattern of alternating straight lines. You may need to periodically rinse the brush in a bucket of water.
To make a series of scallops, use a triangular trowel, sculpting with a semicircular motion.
To produce a spatter texture, dip a brush in a bucket of fairly wet stucco mix and flick at the wall by tapping the brush against a small scrap of wood.
To create a knockdown texture, start with peaks created by pulling back, and gently smooth the surface with a trowel.
Patching Small Holes
Step 1: Clean Hole
Tap with a hammer and chisel to remove any loose stucco. Use a wire brush, then a wet bristle brush, to clean out dust and debris.
Step 2: Attach Mesh
If needed, nail in place a new piece of mesh. Dampen the area with a wet rag shortly before applying the patch.
Step 4: Apply Stucco
Use a putty knife or trowel to apply a ready-mix stucco patch. It may take two or three layers to fill the hole. Allow each layer to dry before applying the next.
Step 4: Add Texture
When you reach the last layer, match the texture. Here, a brush is used in a sweeping, semicircular motion.
Repairing Cracks
Step 1: Widen Crack
Use an old puncture can opener or a detail paint scraper to dig out and widen the crack. Work to make the innermost part of the crack wider than the surface crack.
Step 2: Fill Crack
Apply stucco or mortar caulk, both of which have a grainy texture that blends with a stucco wall. Or to seal but not texture the crack, use regular exterior caulk.