Intro
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.
Prestart Checklist
Time
An hour or less for a small patch (not including drying time); several days for a large patch
Tools
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
Skills
Measuring, laying out a job, driving nails, cutting with a knife
Prep
Protect plants and the lawn with a drop cloth or plastic sheeting.
Materials
Stucco caulk or exterior caulk, stucco patch, stucco mix (basecoat and finish), roofing felt, stucco lath, roofing nails