Funny thing, I’ve seen more mold on window sills in “updated” homes than in old drafty ones. My theory—those older leaky windows let enough air through that nothing stayed damp for long. Once you get those tight seals and double panes, any missed spot in the flashing or a tiny caulk failure and you’ve basically built the perfect little greenhouse for mold.
Had a job last winter where the homeowner swore the new windows were leaking. Turned out the condensation from showers was just sitting on the sill because the bathroom fan barely worked. Even with good exterior sealing, if humidity’s got nowhere to go, that wood’s gonna stay wet.
Ever notice how paint starts to bubble before you see the black spots? That’s usually my first clue something’s up under the surface…
I’m not convinced there’s ever a totally “maintenance-free” window, especially in bathrooms or north-facing walls. Anyone else think ventilation gets overlooked compared to all the talk about caulking and flashing?
I’m not convinced there’s ever a totally “maintenance-free” window, especially in bathrooms or north-facing walls. Anyone else think ventilation gets overlooked compared to all the talk about caulking and flashing?
Nailed it—ventilation gets tossed aside way too often. Everyone obsesses over fancy seals and triple glazing, but if the air inside can’t move, you’re just trapping humidity. I see this all the time on jobs where the windows are technically perfect, but the bathroom fan is ancient or never used. Doesn’t matter how good your caulk job is if you’re basically running a sauna in there.
Funny thing, some of those old single-pane windows with gaps actually helped keep mold down just by letting stuff dry out. Not energy efficient, obviously, but less rot and black spots under the paint.
I tell folks now: even with new installs, crack a window sometimes or upgrade that exhaust fan. And don’t trust those little “trickle vents” to do all the work. Maintenance-free is a myth, especially in damp rooms—just comes down to picking your battles.