Roofs and ice damming.

[hammer]

^Ice damming isn't directly related to gutters. If there is too much heat loss in your attic, the snow will melt from the bottom. The water flows down the roof and freezes at the bottom of the roof (the soffit area stays colder). The ice dam grows from the bottom up.


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Could an ice-clogged gutter cause one? I'm wondering because the north-facing side of my house (which also has gutters) has little to no ice buildup.

 

[Puck it]

^Ice damming isn't directly related to gutters. If there is too much heat loss in your attic, the snow will melt from the bottom. The water flows down the roof and freezes at the bottom of the roof (the soffit area stays colder). The ice dam grows from the bottom up.


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You want to keep the cold as far up as possilbe from the soffit to prevent the damming. I am thinking of adding extentsions to the stryfoam vents from the soffit in between the rafters.

 

[Savemeasammy]

Could an ice-clogged gutter cause one? I'm wondering because the north-facing side of my house (which also has gutters) has little to no ice buildup.

I wouldn't say "cause", but it could contribute. Since the south side gets a greater sun angle, the snow is going to melt faster and end up in your gutters where it can certainly freeze. The north side probably isn't melting as quickly...

You want to keep the cold as far up as possilbe from the soffit to prevent the damming. I am thinking of adding extentsions to the stryfoam vents from the soffit in between the rafters.

Yes, you want your roof to be cold if possible. There needs to be an air space between your insulation and the roof sheathing. It's also helpful if there is minimal air leakage (convective heat loss). A poly vapor barrier is a cheap way to tighten up the insulation job. Installing rigid insulation is another. I may do this in my attic at some point.


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[Bene288]

So today's PSA is brought you by me! In shoveling out the way to our oil fill, I noticed on the side of our house that the snow and ice have dammed up really big. Just a word of advice to all you guys, get your roofs shoveled and ice dams broken up... We have someone coming on Friday (the earliest), but it's a serious matter. Will post photos soon... But yeah this is the one thing that sucks about this epic 2 weeks of snow.

What is the condition of your shingles? If you're going to re shingle soon, make sure to use ice and water shield the first 4 feet of your roof. This will help tremendously, but it needs to be done correctly.

 

[Quietman]

If you have only a small amount of ice than don't worry. Get a roof rake and clear the forst two to three from roof edge. Northly sides will the worse since no direct sun.

I did that once when it was really cold and a new dam formed higher up at the edge of the snow. My house is poorly insulated and the only way to add more would be to drop the ceiling on the 2nd floor(finished attic) and that is way too much $. So I have heating wires and clear the roof after most storms so I don't have to pay for the electricity to run the wires. I've gotten a lot of exercise the last couple of weeks!!

 

[buellski]

We've had pretty significant ice dams in the past. It was so bad that I was going out and raking the roof every time we got even a couple of inches of snow. I bit the bullet and installed standing seam this past summer since we needed to replace the shingles anyway. Huge difference! No more raking and no more ice dams.

 

[dlague]

All this talk in this thread, I think I will look at my roof. Get home when it is dark and then I ski on every day off so I never look at my roof!

 

[ctenidae]

My roof is a Mansard, with basically flat (slightly pitched pyramids, really) on all the tops. Trouble is, the gutters are really just an 18 inch ledge all around, that have filled up with snow, melted to ice, covered with snow. I have to clear them some, at some point, probably by leaning out a 3rd floor window with a garden hoe. Good news is, they've been there for 150 years, hopefully they'll last a few more.

Fortunately, we haven't gotten slammed down here nearly as bad as most of you guys.

 

[freeski]

I rake as far as I can reach every storm. I have had bad ice dams in the past. I've sworn to keep up with it so I don't end up on a ladder with an axe. :smile: This past weekend I shoveled the garage and the top of the roof where I can't get to with the rake. As someone mentioned earlier, I also have a problem with an exhaust fan from a bathroom. I need to check and see if there is something that closes the pipe off when not in use.
If you have ice dams you can buy disks of salt to melt them. They're about the size of a hockey puck and last a long time. Salt probably is not great for the roof, but it's better than having a leak. I have a valley I use the salt in panty hose trick on.
I was surprised how heavy the snow was when I shoveled it this weekend. The snow that fell as fluffy light flakes wasn't that way any more. It was 3' with 4' drifts and I'd guess weighed 35 or 40lbs per square foot.

 

[denny717NHSB]

I have heat tape everywhere and roof rake regularly. I shovel off my porch roof completely every other storm or so, and still got water leaking inside the wall over the porch door.

 

[Savemeasammy]

I have heat tape everywhere and roof rake regularly. I shovel off my porch roof completely every other storm or so, and still got water leaking inside the wall over the porch door.

Probably a flashing issue.


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[freeski]

I had another ice related problem a few years ago in the spring. On the north side of my house there are two basement window wells. I had shoveled the roof and there were snow banks almost up against the wall of the house. During a warm rainstorm the water had no where to go with the ground frozen. The water was rising up inside the well. It was pretty miserable trying to get a path for the water to go with an ice chopper and a shovel in the pouring rain.
It's easier to get the snow away from your house before it sets up like the moguls on avalanche in January. :smile:

 

[bvibert]

I had another ice related problem a few years ago in the spring. On the north side of my house there are two basement window wells. I had shoveled the roof and there were snow banks almost up against the wall of the house. During a warm rainstorm the water had no where to go with the ground frozen. The water was rising up inside the well. It was pretty miserable trying to get a path for the water to go with an ice chopper and a shovel in the pouring rain.
It's easier to get the snow away from your house before it sets up like the moguls on avalanche in January. :smile:

I went through a similar situation a few weeks ago. Chipping away at ice and frozen ground in the rain is definitely not any fun.

 

[from_the_NEK]

I had another ice related problem a few years ago in the spring. On the north side of my house there are two basement window wells. I had shoveled the roof and there were snow banks almost up against the wall of the house. During a warm rainstorm the water had no where to go with the ground frozen. The water was rising up inside the well. It was pretty miserable trying to get a path for the water to go with an ice chopper and a shovel in the pouring rain.
It's easier to get the snow away from your house before it sets up like the moguls on avalanche in January. :smile:

My father-in-law had the same problem last year here in N VT. He woke up to 5 inches of water in his basement. It took about 4 hours to dig out the 6 foot tall snow bank and chip out a drainage path through the underlying ice.

 

[hammer]

And here's the after...wasn't cheap but at least I didn't have to risk life and limb:

 

[xwhaler]

When roofs are cleared is it normally okay to just get the bottom half as shown above? Figuring that most ice dams occur around the gutters?
i.e. if you have space for the water to run off from the top as long as the bottom is clear its a big Win.

I don;t have any ice dams right now but I have a decent size drift where my garage meets the side of the house on the Northwest corner. I'm going to spend some time Saturday getting some of that cleared.

 

[Bostonian]

So here are two "before" photos. Thank goodness the roofer is coming tomorrow.


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[Puck it]

When roofs are cleared is it normally okay to just get the bottom half as shown above? Figuring that most ice dams occur around the gutters?
i.e. if you have space for the water to run off from the top as long as the bottom is clear its a big Win.

I don;t have any ice dams right now but I have a decent size drift where my garage meets the side of the house on the Northwest corner. I'm going to spend some time Saturday getting some of that cleared.

The other problem with drifts is that if they are up against the siding. Water can wick up under the siding and into the walls. I would definitely clear it.

 

[Savemeasammy]

When roofs are cleared is it normally okay to just get the bottom half as shown above? Figuring that most ice dams occur around the gutters?
i.e. if you have space for the water to run off from the top as long as the bottom is clear its a big Win.

I don;t have any ice dams right now but I have a decent size drift where my garage meets the side of the house on the Northwest corner. I'm going to spend some time Saturday getting some of that cleared.

It would be wisest to clear the snow all the way up. If there is snow on the roof, there is still potential for it to melt and refreeze over the eaves... If icicles form on the eaves, and then it snows again, that's a great recipe for another ice dam.

It's also good to get the extra weight off the roof if possible - skiers love craploads of snow. Roofs don't!


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[hammer]

It would be wisest to clear the snow all the way up. If there is snow on the roof, there is still potential for it to melt and refreeze over the eaves... If icicles form on the eaves, and then it snows again, that's a great recipe for another ice dam.

It's also good to get the extra weight off the roof if possible - skiers love craploads of snow. Roofs don't!


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Would agree but we went with the basic solution to prevent more immediate damage. We also had the contractor leave the other areas alone where we didn't have issues. Sure we could have asked but it would have been a lot more $$. Time will tell if we need another visit.