I’m curious—how are folks handling bathroom fans in these newer airtight homes? I keep seeing them vented into attics, which seems like a recipe for mold down the road. Is there a better way that’s actually being used, or just more code loopholes?
Bathroom fans dumping into attics... yeah, I see that way more than I should. Honestly, every time I’m crawling around up there for a roof job and spot one of those flexible ducts just ending in the insulation, I get this mental image of a mushroom farm sprouting above someone’s ceiling. Not exactly the “green” home people are hoping for.
I get that these new airtight homes are supposed to be super efficient, but it feels like sometimes the basics get skipped. My uncle’s place is a good example—brand new build, all the fancy seals and triple-pane windows, but his bathroom fan just vents straight into the attic. He didn’t even realize until he started getting weird stains on the ceiling in winter. Turns out all that steam was just hanging out up there, freezing and thawing. He ended up having to rip out a chunk of drywall and replace some insulation. Not cheap.
I’ve seen a few builders actually run the vent all the way out through the roof or a gable wall, which seems like the obvious move. It’s a bit more work, but at least you’re not turning your attic into a sauna. There’s also those insulated vent kits—kind of a pain to install, but they help keep condensation from forming in the duct itself, especially in colder spots.
Honestly, I think some folks just want to check the “vented” box for code and move on. But if you’re living there, you’re the one who’s gonna deal with moldy smells or worse down the line. If it were up to me, every inspector would have to crawl up there and actually look at where those ducts go... but I guess that’s wishful thinking.
Anyway, if you’re building or remodeling, definitely worth making sure that fan is vented outside for real. Otherwise you might end up with an attic that smells like a gym locker after leg day.
That mushroom farm image is spot on... I’ve seen insulation up there that looked like it was growing its own ecosystem. Do you think part of the problem is just rushed work, or are folks not getting how much moisture can actually build up? I always wonder if anyone’s ever tracked how much damage this causes long-term, especially in colder areas where that freeze-thaw cycle just wrecks everything.
That’s a good point about the freeze-thaw cycle, especially in colder spots. I’m in the Midwest, and I can tell you—when moisture sneaks into the attic or walls, it’s like a slow-motion disaster. I’ve pulled down insulation that was basically a sponge, and the wood underneath looked like it’d been sitting in a swamp. It’s wild how quick things can go south if the ventilation isn’t right.
I do think a lot of it comes down to rushed work, but sometimes it’s just folks not realizing how sneaky moisture can be. It’s invisible until the damage is obvious. I remember when we first moved in, the builder told us “it’s all up to code,” but that didn’t stop ice dams from forming or mold from popping up a couple years later. Makes me wonder if “code” is really enough for these newer, tighter homes.
Have you ever had anyone actually measure humidity or temperature up there? I got a cheap sensor off Amazon and was shocked at how high the humidity got even in winter. It’s almost like you need to be half detective, half homeowner to catch these things before they turn into a science experiment.
I haven’t seen any long-term studies on how much damage this causes, but judging by the number of people I know who’ve had to redo whole sections of their attic, it’s not rare. The worst part is, a lot of insurance won’t cover it if they think it’s “maintenance-related.” That’s a tough pill to swallow when you thought you were buying a well-built house.
It’s easy to feel overwhelmed by all this, but catching it early makes a huge difference. I started just poking my head up there every couple months, especially after big snowstorms or rain. Sometimes it feels like overkill, but I’d rather deal with a little condensation than a full-blown mushroom farm.
That’s honestly one of my biggest worries with our place. We moved in last year and I just assumed “up to code” meant everything was solid, but after the first winter, I noticed a weird musty smell in the closet under the attic access. Turns out there was some condensation up there, even though it’s a new build. I grabbed one of those little humidity sensors too—didn’t expect to see numbers that high in January.
It’s wild how quickly things can go sideways if you’re not paying attention. I agree, code is kind of the bare minimum, especially with how airtight newer homes are. Sometimes I wonder if builders are just focused on passing inspection and moving on. Not saying they’re all cutting corners, but it feels like moisture control is more of an afterthought.
I’ve started checking after big weather swings too. It’s not exactly fun crawling around up there, but like you said, better than dealing with mold or rot down the road. Insurance not covering it is just salt in the wound... makes me extra paranoid about catching stuff early.
