Symptoms
- Fine hairline cracks in a spiderweb or straight-line pattern
- Wider cracks you can fit a coin or fingernail edge into
- Cracking near windows, doors, or corners
Likely causes
- CommonNormal shrinkage cracking as stucco cures and agesHairline cracks are extremely common in stucco and rarely a structural concern.
- PossibleBuilding movement or settlingCracks that are wider, diagonal, or growing can indicate foundation or framing movement.
- PossibleWater intrusion behind the stuccoCracks let water behind the stucco, which can then damage the wall sheathing over time.
What to do
- Measure crack width; hairline cracks under about 1/16 inch are usually just cosmetic.
- Check whether the crack is straight and stable or diagonal, stepped, and seems to be growing over weeks or months.
- For hairline cracks, clean the area and fill with a flexible stucco or masonry caulk, then touch up paint to match.
- For wider cracks, rake out loose material and patch with a stucco repair compound, feathering to match the existing texture.
- Check inside the home near the same area for any matching drywall cracks that might indicate the same movement.
- Photograph and monitor any wider or growing crack over a few months before assuming it's stable.
- Have a foundation specialist evaluate if cracks are widening, stair-stepped, or paired with sticking doors and windows.
Tools and parts
- Putty knife
- Wire brush
- Caulking gun
Flexible stucco patch/caulkSearch: “stucco crack repair caulk”
When to call a pro
Call a stucco contractor for larger repairs and a structural engineer if cracks suggest foundation movement.
Safety
Generally low risk
Generally low risk for a careful person. Stop if anything looks different from what this guide describes.