How a Roof Leak Exposed Hidden Mold at an Issaquah Rental Property

Valta Homes provides property maintenance and management services across King County, WA. We handle everything from roofing and mold remediation to plumbing and gutter services so landlords can protect their investment without the guesswork.

The call came in on a Tuesday. A landlord in Issaquah had noticed a water stain on the ceiling of a second-floor bedroom. It was small. Maybe the size of a dinner plate. They figured it was a minor roof issue and asked us to take a look.

What we found was anything but minor.

That small stain was the visible symptom of a much larger problem. The roof had been slowly leaking for months, water had been pooling in the attic, and mold had already started colonizing the rafters and sheathing. What looked like a quick patch job turned into a full roof replacement and complete mold remediation.

This is the full behind-the-scenes story of how we handled it, what it cost, and what every King County landlord can learn from this project.

The Initial Inspection: What a Water Stain Really Means

When our team member Yao arrived at the property, the first thing he did was get into the attic. That is always the move when you see ceiling stains. The ceiling itself is rarely the problem. It is just where water ends up after traveling through the roof deck, insulation, and framing.

Inside the attic, the picture became clear fast. Water had been entering through a compromised section of the roof near the valleys, the areas where two roof planes meet. Valleys are one of the most common failure points on any roof because they channel the most water during rain. When the flashing or shingles in a valley degrade, water finds its way underneath.

The leak had been slow and steady. Not enough to cause dramatic dripping or visible flooding, but more than enough to keep the attic sheathing damp for weeks at a time. And that is exactly the environment mold needs to thrive.

The Mold Discovery

Our team used a thermal imaging camera to map the moisture in the attic. The thermal scan lit up several sections of the roof deck where moisture had been sitting. Where there was moisture, there was mold.

The mold had spread across several rafters and along portions of the sheathing. It was not the dramatic black mold that makes headlines, but it was active growth that needed to be addressed before any roof work could begin. If you replace the roof without treating the mold underneath, you are just sealing the problem inside.

This is something we see regularly in the Pacific Northwest. Our climate, with months of steady rain followed by mild temperatures, creates perfect conditions for mold growth in attics, crawl spaces, and anywhere moisture gets trapped. If you own a rental property in King County, attic inspections should be part of your annual maintenance routine. (We wrote a full that covers this.)