What We Found Behind the Wall
Dave cut a small inspection hole below the window. The smell hit us immediately. Musty, earthy, wrong. Behind that rippled paint was drywall so saturated it peeled apart in layers. Black mold spots dotted the paper backing.
The source was obvious once we could see inside the wall. The flashing above the window had failed. Every rain since who knows when had been trickling down between the siding and sheathing, pooling on the window header, and wicking into the drywall.
The damage extended two feet past what was visible on the surface. In Ballard, where rain falls sideways during winter storms, water finds every gap.
The Repair Process in Seattle's Wet Season
Timing a repair like this in Seattle is tricky. You cannot leave a wall open during rain season, but you also cannot seal up moisture behind new drywall. Dave had to work in stages.
First, the mold remediation company came. They removed all affected drywall plus six inches beyond the visible damage. They treated the studs with antimicrobial solution. Cost for that phase: $1,800.
Then Dave had a window contractor fix the flashing. Another $650. The old flashing had been installed flat instead of angled, so water sat and eventually found its way in.
Finally, Dave rebuilt the wall himself. New insulation rated for wet climates, new drywall, tape, mud, texture, paint. His material cost was around $200. If he had hired the labor, that phase would have added another $800 to $1,000.
Warning Signs Seattle Homeowners Should Watch
After Dave's experience, I started checking my own Fremont house more carefully. Here are the early warning signs to catch before you have a four-figure repair:
- Paint that feels cooler than surrounding areas (indicates moisture behind)
- Slight waviness in otherwise flat walls
- Musty smell near windows during rain season
- Baseboards that feel soft or show discoloration at the bottom
- Condensation on window frames that drips onto sills
A moisture meter costs about $25 on Amazon. Dave wishes he had checked his walls when he first noticed the ripple.
Seattle-Specific Moisture Prevention
Dave's house was typical Ballard construction from that era. Single-pane windows, minimal insulation, no rain screen behind the siding. Modern Seattle construction handles rain better, but older homes need attention.
He added these upgrades after the repair: extended downspouts away from the foundation, resealed all window trim, and installed a dehumidifier that runs October through April. His energy bill went up $20 a month, but he figures that is cheap insurance against another $4,200 disaster.