I may have ice damming, do I need a new roof?

A few days ago I was down in my basement and noticed a bit of water dripping from pretty high up the wall. I have a few vertical cracks in my poured concrete foundation that will leak a bit when it’s pouring outside, but this was different, it’s not raining, it’s not warm enough to cause enough of a melt and this was in a different place, it was much higher up.

Upon closer inspection I noticed that it was coming from above the foundation. I just assumed there was snow against the outside wall. I went outside and found not only no snow anywhere near the house, but a little bit of water dripping down from under the siding (the siding goes past the top of the foundation as you would expect).

I went back down to the basement to get a better look. I put my hand up on the sill plate and found it not just wet but a bit rotten. Not to the point that it needs to be replaced, but it’s clear this has been going on for a while, it’s just the first time I’ve noticed it and/or the first time it’s happened to the point where the water has dripped down the wall. My guess at this point was that water is entering the roof, coming down between the siding at wall, over the sill and into the basement.

Today I finally got a chance to get into the attic. The first thing I did was to walk outside and see what I could see. Snow was melting around the bathroom fan vent.
Went into the attic and sure enough, in that general area it’s clear there’s been water penetration. I can see black stains, I can see some in another section as well, I’m not sure if that’s another problem or part of the same issue though (could go either way). The vent is very very close to the eve, far closer then I’m able to finagle myself into without getting hurt so I couldn’t get a good look at it. I’m sort of hoping that maybe it’s just disconnected. If that’s the case, it could just be steam from the shower condensing on the underside of the roof, wouldn’t that be an easy fix. If that’s all it is, I’ll find a way to get in there and fix it myself. I think my next step is to take a long hot shower (or just fill up the bath with hot water) without running the fan on a cold day and then turn it on and go outside. I should be able to see steam pouring out the vent. I’m guessing, however, that the vent is just fine as I only saw the problem in that one area. If it wasn’t connected I’d imagine I would have seen signs of the water damage/mold all the way up to the peak. Also, the snow was pretty evenly melted all the way around the vent outside. I don’t think that would happen if it wasn’t connected.

Anyways, if I am having damming issues, is that something I would need to replace the roof to deal with? I know the roof is about 15 years old and it wasn’t done that well to begin with. Also there’s a skylight that needs to be replaced as well so it’s not the end of the world. It would also mean, if a tearoff (or partial tearoff) is done the couple of pieces of sheathing that have mildew on them can be replaced right away as well. I know you don’t have to do a tearoff if you only have one set of shingles, but I figure if I have the money now, might as well do it now, rather then having to tearoff 3 roofs when I don’t have the money (of course, by then it might be someone else’s problem)

I was >< this close to having my Line of Credit paid off. Seriously. A month or two, a tax refund, maybe another month or two and the LOC would be gone. I guess it’s better that I found this out now, I’d rather owe on the LOC for another year then have to save up for a year to get a leaky roof fixed. Remember leaks get bigger not smaller.

You shouldn’t have to replace the roof. If it’s been going on for some time, you may have to replace some of the underlayment sheets (plywood or OSB), and whatever shingles have to be removed to get to the underlayment. A roofer can pull up some of the shingles to see what’s going on under there. It would be an excellent idea to have the roofer install ice shield up to a distance of about 3’ from the eave, regardless of the condition of the plywood. This will help prevent the same problem from occurring. You should also have someone check on your attic insulation and whether or not your attic is properly ventilated. Vents and blown in insulation are the best prevention for ice damming.

Some people like to install thawing circuits along the roof eaves. They work pretty well, and you don’t have to tear up your roof to install them. But if the underlayment is damaged, you have to do that anyway and might as well do the ice shield. In any case, you should have the insulation and venting looked into.

Another potential problem is that you could have a lot of water damage inside your walls, including mold. Hopefully that is not the case. As a quick fix to the damming, call someone right away to come out and chip the ice off your roof. We had to have that done; it was like a freaking glacier up there. I saw one foot thick chunks flying off. That will stop any further damming probably for the rest of the winter, and you can address any possible problems/fixes come spring/summer. That will also give your walls time to dry out. You might want to find some portable forced air heaters, point them at your walls, turn them on and let them run all day (once the damming is addressed).

I know the insulation is good (I’ve seen it), I also know the ventilation is good (again, I’ve seen it), it’s also freezing cold it the attic, which is good.

Something else I didn’t mention is that I don’t have tons of snow or ice up on the roof. There’s some ice in the gutter, but it’s certainly not backing up onto the roof and the area where I see the black spots in the attic (on the underside of the roof) have no snow or ice on them at all, anything that melts there would run right past it.

So, I might have (or had) ice damming, I might just have some leaks. I suppose it’s also possible it wasn’t damming at the gutters, it was damming right by the bathroom vent.

We had this problem very badly one winter about 20 years ago. I thought for sure we’d have to replace the roof.

We didn’t, and everything turned out to be just fine.
Like Chefguy, we did get someone to shovel some of the snow and ice off the roof–in this case, just the bottom 3’ or so.

Mn roofer.

Ice dams are a symptom of poor insulation and ventilation, not a failing roof. You can get an energy audit to see where the issues are.

You can’t put another layer of singles on top, typically it’s against code, and most manufacturers won’t warranty their shingles.

Mn code is 24" from exterior wall, which typically means 6’ up from the eaves, not three.

Too hard to tell what is going on without pics, or on-site.

Some roofers will warranty the work if it’s only the second layer of shingles being put on, but it’s a bad idea, as you know. From the OP’s description in his follow-up post, it doesn’t sound like ice damming. For one thing, he’s finding rot, which indicates a long-term problem. Secondly, he’s not seeing ice and snow buildup on his roof, which to me screams LEAK! and not damming. Thirdly, his attic is very cold, which is what is needed for a cold roof, and which means that the insulation and ventilation is probably adequate. Ice in the gutters can be a problem, as melt water can back up under the eave shingles.

You may indeed be looking at shingle replacement and probably some sheathing replacement. The rot should be remediated, also, but perhaps you could do it if you have some carpenter skills. Check Angie’s list for bargains.