Funny, your story reminds me of what happened at my place in central Vermont a few years back. We’d always had a cold attic—barely any insulation, drafty as heck, but never much in the way of ice dams. Then, after a particularly nasty winter, I decided to go all-in and had cellulose blown in up there. Figured it’d be a game changer for heating bills. Instead, that next winter, we got these monster icicles hanging off the gutters and—just like you—water started sneaking in around the chimney flashing.
Turns out, it wasn’t just about adding insulation. The old setup let enough heat escape that the whole attic stayed nearly as cold as the outside, so snow on the roof didn’t melt much. Once we tightened things up, the little bit of heat that did leak through started getting trapped under the roof deck, especially since our soffit vents were partly blocked by the new insulation. That warm patch melted the underside of the snow, which then refroze at the eaves and made those classic ice dams.
Low-pitch roofs seem to make it worse, too—less room for airflow and less chance for snow to slide off naturally. What finally helped was crawling up there (not fun in January) and clearing out the soffit vents, plus adding a couple of roof vents higher up. I also found a couple of spots where warm air from the bathroom fan was leaking into the attic instead of venting outside. Sealing those up made a difference.
I don’t think you can really “over-insulate” if you’ve got good airflow, but if you block off those vents or miss some sneaky air leaks, it’s almost like you’re trapping the problem inside. Every house is its own puzzle. Sometimes I think the only universal rule is that nothing ever goes exactly by the book...
I get the whole “it’s not just insulation” thing, but I’m still not convinced you can’t overdo it. When we bought our place (upstate NY, low-pitch roof), I went heavy on insulation and air sealing, thinking more was always better. Ended up with way more ice dam headaches than before, even though I thought I’d left the vents clear. Maybe airflow helps, but I swear there’s a point where packing in too much just creates other problems—like moisture getting trapped. Sometimes feels like you fix one thing and two more pop up...
That’s pretty much what happened to us, too—went all-in on insulation and sealing, thinking it’d be a cure-all. Next winter, we had monster icicles and water sneaking in around the eaves. I’m starting to think there’s a sweet spot with insulation, but if you mess up the airflow even a little, it backfires. Anyone else notice that sometimes those baffles or vents get blocked by shifting insulation over time? I keep wondering if the low-pitch roof just makes it harder to get the balance right.
Yeah, I’ve definitely noticed the insulation shifting and blocking those vents, especially after a rough winter or if someone’s been crawling around up there. My place has a pretty shallow pitch too, and it seems like the airflow just never works as intended. I tried adding more venting, but honestly, it’s a constant battle to keep everything clear. Anyone else ever just get up there and find the baffles totally buried? Makes me wonder if there’s a better way to keep them in place...
Baffles getting buried is a pain, especially with low-pitch roofs. What I’ve done for a few clients is staple the baffles directly to the rafters, then use a bit of spray foam at the edges to lock them in place—just enough to keep insulation from creeping in, not so much it blocks airflow. If you’re dealing with blown-in insulation, you might want to add some rigid foam board as a barrier right at the eaves. It’s not perfect, but it’s held up better than just relying on friction or gravity.
