What it is, how it works, and the questions to ask before you hire.
Last updated: October 2026
Stucco is a cement-plaster exterior — traditional three-coat over lath, or newer one-coat and synthetic (EIFS) systems — most common in the Southwest and Florida. It handles dry heat superbly and gives homes their distinctive look. Its weakness is singular and serious: cracks that admit water into a wall assembly that dries slowly. This guide covers how stucco systems work, how they fail, and why crack repair is about water, not appearance.
Most hairline cracks are surface-level and cosmetic — stucco is a brittle material and fine cracking is normal as it cures and ages. Cracks matter when they are wide, follow a pattern (stepped, diagonal from window corners), keep reopening after repair, or come with staining and soft spots: those admit water, and water behind stucco is the real problem. A crack that lets water in should be sealed promptly even if it looks minor.
Traditional stucco is hard cement plaster over metal lath — heavy, rigid, and it rings solid when knocked. EIFS (synthetic stucco) is a thin polymer coating over foam insulation board — lighter, slightly springy to a knock, and entirely dependent on its sealant joints and flashing to keep water out of the foam-and-sheathing assembly. They are inspected and repaired differently, so identifying the system is step one.
Yes — damaged sections can be cut out and re-plastered, and cracks can be routed and sealed. The challenges are texture and color matching: patches weather differently from the original surface, so repairs on prominent walls often end with a recoat of the whole elevation for a uniform finish.