研究の知恵

Why Your Roof May Be Breeding Mold Colonies

Imagine walking into your attic on a damp afternoon and being hit by a musty, earthy smell—like wet soil after rain, but less pleasant. That’s what Linda, a homeowner in Portland, Oregon, experienced last spring. At first, she brushed it off as “just seasonal humidity,” but when her 8-year-old’s allergies flared up with relentless sneezing, she called a local inspector. What they found shocked her: black mold colonies spreading across the roof’s wooden beams, thriving in the moisture trapped under damaged shingles. “I never thought my roof—something I barely look at—could make my kid sick,” she later told friends. Linda’s story isn’t unique. Across the U.S., from the rain-soaked Pacific Northwest to the humid Southeast, roofs quietly become mold hotspots, often unnoticed until problems escalate. Here’s why your roof might be hiding this unwelcome guest—and what you can do about it.