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I live in Minnesota in a single story rambler with full basement. In an upstairs corner bedroom I started noticing some water leaking in the closet ceiling a week or two ago (picture is current, it started much smaller).

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We've had a record amount of snow fall this year. When I first saw the leak, I realized that my roof vents were covered with snow. On Christmas day, I shoveled off the entire roof. Since then we've had a few light snows and warm days too, so there's been some accumulation then melting. Right now there's nearly no snow on the roof, and the gutters still have some ice in them.

But the leaking is getting worse. Now has spread across the entire edge of the wall.

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There's also water dripping into the inside of that window, and there's a stalagmite icicle in one of the windows about 6-8" tall.

Today I went into the attic to look for a leak. I was unable to find one, however.

There were a couple spots under vents or pipes were a little frost came through and melted, and underneath the insulation was slightly damp (and frozen).

But, as best as I could see, near the edge of the house above the ceiling in the pictures, there was no evidence of wetness or frozen water. Not any amount I would expect to see based on the damage. Now, on the roof above there is a thin layer of frost - across much of the length of the house actually. Could that be melting on warm days and dripping down? But yet I don't see any wet spots, if I push the insulation away I can see the wet ceiling board, but the insulation isn't really wet and there's no signs of where it's running down from and dripping from.

There were also a a spots where the insulation was contacting the roof at the edge of the house, directly above where the leaks appear. I thought perhaps moisture was being wicked down. I've moved the insulation so that it doesn't contact, but again it wasn't wet indicating that it was the source of the leak.

How do I figure out what needs fixing here?

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Is the affected side of the house facing the wind? Is there a gutter just above that window? This might be a long shot, but wind could be forcing snow up into the soffit where it melts and runs into the house. –  Tester101 Jan 10 '11 at 13:31
    
It sees some wind, but that seems like a long shot. I can see from the attic the ceiling board that's wet, and frankly the soffit vent isn't exactly close to it, plus it's substantially lower so the snow would have to travel upwards more than I'd think it could. –  qes Jan 10 '11 at 16:05
    
It is now February have you figured out what happened? We have same issue and roofer basically said there is nothing to do about it? I can't believe this is true? Water getting in and leaving stain on ceiling-that can't be good? What about mold? –  user1743 Feb 8 '11 at 23:17
    
@Frustrated in op - This is still happening, I have not solved it. Roofers tell me that the moisture barrier (has a special name I cannot recall) has been breached by ice dams and it requires repair/replacing at this point. –  qes Feb 8 '11 at 23:21
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3 Answers 3

All the advice so far about ice damns is valid. However, if there are no dams or visible water on the roof, then you will need to crawl up in the attic and start looking for the wet areas that are wicking into your ceiling. The insulation may have been soaked before you got a chance to clear the roof. Obviously if wet insulation is found, it must be removed. Another problem I have come across in a few situations like yours, no dam, but slow moisture stains keep developing, came from improperly installed "proper vent" from the soffit vents to the air space in the attic. In a few cases, the open upper end of the proper vent was blocked or covered with insulation and condensation formed on the top side of the drywall right along the wall. In a couple of cases, no venting was used from the soffit and insulation was packed into this area instead. In either case, you will have to get up there and move the insulation in the affected areas and look for the moisture. Also look for any tell-tale water stains on the rafters or trusses that may have been a leak from above.

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Was just thinking.... is any section of ceiling close to the leak unusually cold to the touch as compared to the rest of the ceiling? That is a good clue to solve your problem. –  shirlock homes Jan 10 '11 at 16:06
    
I'll get up again and take a closer look (tough to get all the way to the edge), but that is exactly what has me confused. Where I would expect to find evidence of a leak - in the insulation above - I do not. I can move the insulation and see the wet ceiling, but there isn't wet insulation above it, nor wet trusses. –  qes Jan 10 '11 at 16:06
    
The wall and ceiling are quite chilly, yes. The whole room is quite cool. I have left it unheated and closed up for most of the winter. Although, last night I opened the door and vents and the water droplets hanging from the ceiling have dried up. –  qes Jan 10 '11 at 16:07
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the reason I asked about an abnormally cold ceiling or top of wall was to determine if maybe insulation had been moved or settled in a specific area causing a cold surface for moisture in he house to condense on.. If you are absolutely sure there is no moisture above the area in question, then I bet it is condensation on the inside surface only. –  shirlock homes Jan 10 '11 at 19:54
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Is it all along an exterior wall? If so, it might be a sign of ice dams. You won't see obvious signs, other than wet spots if you were to look at the underside of the roof.

It's possible that a blocked roof-vent might contribute, if the attic warms up and can't escape. (I'm assuming that you have a cold attic, where the floor of the attic is insulated, not the roof line). I'd try to get the insulation away from the roof-line, especially if you have soffit vents. You may be able to just pull back the insulation and install an insulation baffle, but you may have to trim back the insulation so you're not compressing it too much. (compressed insulation == no trapped air == bad R factor)

You said the roof was cleared off, but take a look right where the exterior wall of the house hits the overhang -- as it's a single story, you might be able to see without a ladder, but I'd take a broom and sweep off the snow, and see if there's ice-buildup. If so, that's likely the culprit.

It's also possible that as you went up on the roof on Christmas day that you've damaged the roof, but then it'd most likely be localized in a spot or two, and not as likely to be along a whole external wall.

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The attic is cold. I do have soffit vents, and in some areas baffles are used. the insulation is loose and so I simply moved it where it touched the roof. There's no significant ice under the overhang. Possibly some I have not seen (haven't yet waded through the 4 feet of snow in the yard to get close), but there couldn't be much (can see it from the street). –  qes Jan 10 '11 at 5:46
    
@qstarin : freezing, or just cold? this time of year, you need it below 32F / 0C. –  Joe Jan 10 '11 at 7:57
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It certainly seems to be below freezing, but I haven't measured. Not sure how it might be on a sunny day. Snow on the roof has melted on some warm days, but there's frost on the tips of the nails poking through the roof, and a couple spots near vents where I could find evidence of very minor leaks that water was frozen in the insulation (very small amounts). –  qes Jan 10 '11 at 8:40
    
There are exposed nail heads on the roof? I think you just found the source of your leak... –  Cody C Apr 25 '12 at 14:55
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While it's probably much more likely you do have a leak somewhere, you may consider checking the humidity inside your house as well.

If there's significant moisture in the air, it's possible that it's simply condensing on the coldest surfaces it can find. The corners are going to naturally be those spots.

You would certainly have significant condensation (which you also mentioned) on your windows if this is your cause.

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Judging by how much water is on the ceiling, and how much is on the windows, I would say this is not the case. Temp in that room is 55-60* F and relative humidity is 40-60% (I happen to have measured). The windows themselves do not have much moisture/ice on them. –  qes Jan 10 '11 at 19:11
    
Condensation would be my guess as well. In winter, you should be shooting for about 20% humidity in Minnesota. Have you updated your furnace to a high efficiency model over the last year? Have you upgraded the windows? Both of these things will increase your indoor humidity during the winter. Try running a dehumidifier in the affected areas, and see if the problem goes away. –  James Van Huis Feb 8 '11 at 23:34
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FYI, back of the envelope suggests that in a 15x15x8 foot room at 60 degrees with 60% RH, you will have approximately 9 ounces of extra water in the air. The dew point at those conditions will be approximately 45 degrees. Any surface in the room which is at or below 45 degrees will collect condensation. –  James Van Huis Feb 9 '11 at 20:22
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