Dispelling myths about stucco siding
Stucco siding on homes often gets an unfairly bad rap.
Q: I have been told that if you buy a home with the exterior having stucco, you are just looking for trouble. I have looked at a home that I just love but it has stucco on the outside.
A: That couldn’t be further from the truth. Like any siding, it depends on whether it is installed correctly and properly maintained.
Stucco is water resistant and weatherproof, but is permeable to water vapor to let moisture escape from the wall. If water penetrates the finish through cracks or there is moisture buildup in the wall, stucco can deteriorate. Watch for defects in gutters and downspouts, flashings and drip edges that can cause water to leak behind the stucco.
Inspect stucco walls for cracking and try to find the cause of it. For cracks that go through all layers, cracks that hold water, and offset cracks and breaks in the stucco, I would recommend immediate repair. Cracks can appear in stucco over wood framework when framing members shrink, especially at floor level, where there is the most shrinkage. Vertical and horizontal cracks can take place when there is some foundation settlement. Cracks in all directions can appear during the curing process of the stucco. These can be hairline cracks or be deeper involving the under coats.
Stucco can be detached from the wall due to trapped moisture — bulging and sagging can be a sign of that. A homeowner often will paint the stucco with impermeable paint. Stucco should be painted with a permeable masonry paint, which allows moisture to escape. You can tap the wall with a screwdriver handle and listen for signs that the wall is detaching. Areas in the wall coming loose will make a dull thud when tapped. Acrylic stucco, the kind most commonly used, is applied over polystyrene sheets and fiber mesh netting. Push against the wall with your hand to see whether the surface is pulling away from its polystyrene base. It is a good product.
When you build a home, what you choose for siding — stucco, brick, wood, vinyl, composite — depends on the quality of the installation. In our area, we are lucky to have many quality builders that take pride in their work.
—Rich Duerkop of American Sentry Home Inspection is a state-licensed home inspector and president and education director of the Wisconsin Association of Home Inspectors, Central Wisconsin Chapter. He can be reached at 715-241-8222 or by email at americansentry1@charter.net.