It seems to me that people in cold states/Canada would have a horrific problem with ice dams on the

[raccoon]

roof. What can be done to mitigate it?

Though I don't live in a cold climate I used to live in a very old, un-maintained house, with a horrific problem of ice damming when it got real cold. (How did I solve the problem? I didn't, I moved and the house was torn down.)

[Jackpine Radical]

1. That's cheerful.

I was just sitting here trying to figure out what to do about my %$$#@^&& ice dam.

[Monsoon]

2. Proper ventilation of the attic and adequate insulation

Ice dams occur when the underside of the roof warms up to melt snow on top, the water refreezes when it hits the cold overhang and creates the dams.

[safeinOhio]

3. Poor attic insulation

is the usual cause.

[Schema Thing]

4. northern building codes now require Ice & Water shield

underlayment on the first few feet of all new roofs. I wouldn't be surprised if they don't also require certain insulation and ventilation procedures in the eaves of all new buildings.

[SPedigrees]

6. Those measures don't help much.

Our house has them and I just finished laying bath towels across the indoor windowsills and floor to catch the stream of water while I prepare to don boots, coat etc and go out to do battle with the 4 foot icicles and the wall of ice attached to them. Is summer coming back soon?

[TheCowsCameHome]

5. I had trouble once..

..insulation ended the trouble.

It's a pain, when not corrected.

[Maine_Nurse]

7. Cold roofs work well

and have been around for a long long time.

[Arger68]

8. Honestly the best way to prevent ice dams

is to rake the snow off of the bottom few feet of your roof. That is what I do. My attic is well insulated so I really don't have much problem but simply removing the snow solves the problem. On the other hand, old houses with really tall roofs are probably not very easy to rake the snow off of.

[Maine_Nurse]

9. Unless you are super-insulated

you need to do more than the bottom few feet if you are somewhere that has freezing temps for many months on end. The area around the peak has the highest head loss (thus melting) which trickles down to a colder point where it freezes and builds up over time. The worst time is when you have a stretch of weather that is in the mid to high 20's. Then it only takes a little heat loss to melt stuff, but it will still freeze up on the eaves.

[Altoid_Cyclist]

10. We had pretty good luck with heating cables.

It does add to the electric bill however. I try to use a snow rake now that we removed the cables, but we still have a few small ice dams this year. Last year we had to use a lot of towels and tin cans around our bedroom window.....that was pleasant.

I think that we might go back to the heating cables for the two trouble spots at least.