Coincidentally, this story took a turn. We ended up calling the roofing company that redid ours this past summer and the problem, it seems, is in the added insulation they put in on part of the roof (our house was built in 1920, but in the succeeding years, two extensions were put on in the back, with varying insulation, so when they resurfaced the roof, they put in a layer of insulation). They think that a weird venting issue has led to the new insulation trapping the heat and warming the roof in those spots, leading to the new melt/freeze. So, they removed the existing ice and installed a heating cable in the eaves, and then in the spring they're going to look at installing another vent.Spiff wrote: ↑16 Jan 2018, 10:20amYou have a flat roof?Dr. Medulla wrote: ↑02 Jan 2018, 7:42pmIn other weather-related homeowner news, when we had our roof resurfaced this summer, the slope was altered (it's a French-Canadian flat-style roof), which changed part of where water drains. We don't have much insulation in our attic, which I'm fine with because it melts the snow up there, keeping it from building up. But now, in the new drainage pattern, part of it is going to an area without an eavestrough and landing on a lower roof and freezing (as well as creating an ice giant up the side). So I went out and bought a deicing cable. I know it's not meant for flat roofs, but there is enough of a pitch that the water will definitely drain rather than pool. Tomorrow I'll be hooking it up to melt the ice and bring peace to the troubled land once more.
Moral of the story: There are times I wish I had a landlord to take care of this crap.
Who the fuck builds a flat roof in the great white north?
Anyway, are you sure that having so little insulation in your attic is the right way to go?
You're using a lot of energy to heat your roof to melt the snow off of it, and that's a shame, both to your pocketbook, plus that's what's causing the ice dams that are causing you grief.
I'd get a good house engineer to come out and take a look at your situation.
As for your other comments, a flat roof is nuts, I know. I grew up in a-frame country and the idea of a flat roof still freaks me out (which is why I'm up there cleaning things off so often). But that's a French-Canadian architecture that's common to older homes here. As for heating costs, our winter bills are quite low—we bought a top-of-the-line high efficiency furnace when we bought the place and we don't run the heat very high. Given my anxiety about having snow built up on a flat roof, I'm good with it melting—as long as it then drains. And when the roofing guy showed up, I got to take a look at the attic—crawl space, really, maybe a foot high—there's a lot more insulation than we were led to believe. The roofer didn't think that was the problem—it was, oddly, new, solid insulation up top.