"ventilation helps, sure... but it's not always the root cause of moisture problems."
Couldn't agree more with this point. A few winters back, I had a similar experience. Our attic had decent ventilation—ridge vents and soffit vents were all clear—but we still had ice dams forming every winter. It drove me nuts because I thought we'd done everything right with airflow.
Finally, after talking to a neighbor who'd dealt with the same issue, I decided to tackle air sealing. Spent a weekend crawling around the attic with a caulk gun and foam sealant, sealing up every little gap and crack I could find. The recessed lights were especially bad—could literally feel warm air blowing through some spots. After sealing those and adding another layer of insulation, the difference was night and day. Ice dams practically disappeared, and our heating bills dropped noticeably too.
One thing I'd add is that sometimes builders overlook the importance of sealing around chimneys and plumbing stacks. Those areas can be sneaky culprits for air leaks, even if your insulation looks good overall. Also, older homes often had fewer moisture issues partly because they weren't as airtight as modern builds—ironically, the natural drafts helped dry things out. With today's tighter construction, any small leak from conditioned space into the attic can quickly become a moisture trap.
Ventilation definitely matters, but it's just one piece of the puzzle. If you're building new or renovating, I'd say prioritize air sealing and insulation first—then make sure your ventilation is adequate. Doing it in that order seems to give the best results, at least in my experience.
Great points about air sealing—hadn't really thought about recessed lights being such a big deal. Makes sense though, since heat rises and all. Wonder if anyone's noticed moisture issues improving just by switching to LED fixtures that don't heat up as much?
Switching to LEDs might help with heat, but moisture issues usually tie back more to ventilation and insulation quality. Have you checked if your attic vents are clear and properly sized? Sometimes builders skimp a bit there. Also, bathroom fans—are they venting straight outside or just dumping humid air into the attic? I've seen that happen more than once, and it causes way bigger moisture headaches than recessed lights ever could...
Had this exact issue when we moved into our place. Turns out the bathroom fan was just venting straight into the attic... easy fix though—just added some ducting to route it outside and problem solved. Worth checking yours, might save you some headaches down the line.
"Turns out the bathroom fan was just venting straight into the attic..."
Had a similar experience inspecting a newer build last year—fan vented straight into the attic, insulation already damp and mold starting to creep in. Makes me wonder how common this oversight really is. Do builders just assume homeowners won't notice, or is it genuinely overlooked during construction? Seems like such a basic thing to miss...
