Stucco water damage in Tucson

Monsoon storms drive rain horizontally against walls that have spent months baking and opening up fine cracks. Water goes in through those cracks, past the finish, and into the assembly behind it. A stucco wall holds that water rather than shedding it, and in a wall cavity it can sit against sheathing and framing for a long time.

The damage is therefore usually much older than the symptom. By the time there is a stain inside, or soft stucco at the base of a wall, water has been getting in for at least one season and often several. That is why the honest version of this work involves opening the wall rather than sealing the outside and hoping.

Signs water is getting in

• Staining or a tide line inside on an exterior wall
• Soft, crumbling or sandy stucco near the bottom of a wall
• Bubbling or peeling paint on the exterior
• A hollow sound over an area when tapped
• Efflorescence, the white powdery deposit, on the surface
• Stucco that runs down into the soil with no visible weep screed
• Damage concentrated below windows or at roofline junctions

How water intrusion is handled

Find the entry point, which is rarely where the damage shows. Water tracks down and sideways inside a wall. Common Tucson entry points are window and door perimeters where sealant has failed, roofline and parapet junctions, penetrations for hose bibs and electrical, and the bottom of the wall where stucco has been carried down into the dirt.

That last one deserves its own mention because it is so common here. Stucco is supposed to terminate above grade at a weep screed, which lets any water inside the assembly drain out. Where stucco runs straight into the soil, moisture wicks up into the wall continuously and no amount of surface sealing stops it. Correcting that termination is real work and it is the actual fix.

Then open, dry and rebuild. Damaged stucco removed, wet paper and rusted lath replaced, substrate checked and repaired, and the assembly rebuilt properly with correct flashing and sealant at the perimeter. Then finish and texture matched back in.

In Barrio Viejo and South Tucson, cement stucco applied over old adobe traps moisture and erodes the wall from the inside while it looks sound from the street.