Wow, I live in the Land of the Great Two Ton Ice Dam, and there is one way to prevent them. Insulate & vent.
Then again, if you have a tin roof....Invest in Pam. And duck a lot.
We had 16" of blown-in in ours, two years ago ADDED 19" more, no ice damming since. If the heat from inside can't get up there, there is no way for ice damming to occur.
Except of course if you get three inches of freezing rain first. But that should still not slide if the heat from inside isn't getting to the rafters to melt it loose.....
Scoville DeVille said:
Exactly. I need to wait until it thaws and dries out which means it will be hot AF up there. Probably why I haven't done it in 3 years. There is also like an inch thick layer of Hores frost on the under side of the roof where the worst heat loss is. I'm sure running our humidifiers doesn't help with that. Heat loss + moisture = bad scenario. There's probably bats and shit living up there too. LOLOL
Scovie, YOU gotta do more than insulate, and boy will you hate this: seal the lid. Some electric co-ops offer a free inspection, finding all those sneaky breaches, some you'd never suspect. We had an uninsulated chimney cause all kinds of problems, it was cheaper to remove than seal and insulate. We save a lot on heating too by not losing heat to the attic. But it weren't no fun, boy.....