Author Topic: Moisture in the attic  (Read 495 times)

saijoe

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Moisture in the attic
« on: January 08, 2018, 10:16:16 AM »
I am in the Chicago area.  We noticed a water stain on our bedroom yesterday morning.  I looked up in the attic and there was frost and moisture all over.  It has been really cold here the past couple of weeks and yesterday was warmer, though still below freezing.  I went to the big box store, bought an attic fan and rigged it to blow out to pull in fresh air.  This seemed to have helped. 

In general, what causes this? 

mikedom

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Re: Moisture in the attic
« Reply #1 on: January 08, 2018, 10:40:24 AM »
Any bathroom fans that are venting directly into the attic? It looks rather localized.

Papa bear

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Re: Moisture in the attic
« Reply #2 on: January 08, 2018, 10:44:25 AM »
Could be an ice damn. That's where the warm air in the attic makes some snow, then it freezes lower on down, and traps liquid water on your shingles, which allows it to enter your home.

Do you have major icicles?  That's a sign of poor attic ventilation too.  Make sure your soffits are free from insulation and it allows air to enter. 


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Sibley

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Re: Moisture in the attic
« Reply #3 on: January 08, 2018, 12:06:21 PM »
Yes, check for ice dams. Good news is it's going to warm up enough this week to melt anything on the roof, bad news is the evidence will melt away.

Jon Bon

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Re: Moisture in the attic
« Reply #4 on: January 08, 2018, 02:34:14 PM »
Leak?

That looks like its at the peak of the roof, a very odd place for an ice dam. Honestly an odd place for it to leak and freeze either.

The ventilation looks decent from the picture.

I say leak for bathroom vent is disconnected.

BudgetSlasher

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Re: Moisture in the attic
« Reply #5 on: January 08, 2018, 06:11:47 PM »
To me it looks like there moisture (and probably heat) escaping form the house and then freezing on the framing. If there anything below like a bathroom vent line, a junction box with big air gaps around it, the attic access hatch or something of the like?

More pictures or better lighting would be helpful; you say that it is everywhere, but I can only making it out on the framing. Unless what I am assuming is insulation in the bottom of the picture is something else . . .


Sun Hat

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Re: Moisture in the attic
« Reply #6 on: January 14, 2018, 06:51:03 AM »
I noticed similar frost in my attic last weekend when I was up adding insulation. As it was especially bad in the vicinity of the plumbing vent stack, my guess/hope is that convective heat loss is causing condensation to form and freeze. I'll update in a week to let you know if adding insulation results in less frost. Personally, I'm really hoping that it's not moist air leaking into the attic, since I did my best effort at leak-proofing before adding the insulation, and now it'll be a nightmare to do further work.
"You need a little bit of insanity to do great things." ~ Henry Rollins

Cyanne

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Re: Moisture in the attic
« Reply #7 on: January 14, 2018, 09:22:23 AM »
We had a similar problem after the last cold spell. We had multiple drips from our ceiling in two different rooms in a section of our home. It was not an ice dam. It was caused by condensation of moist air, freezing and then melting and dripping back down when it warmed up. This website explains it. http://www.drroof.ca/industry-topics/ice-dams/

We have lived here for 15 years and this is the first year we have experienced it. I think our furnace humidifier was set too high combined with the extreme cold snap that caused it.

Sun Hat

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Re: Moisture in the attic
« Reply #8 on: January 14, 2018, 05:15:10 PM »
Thanks for the link Cyanne. I judging by the info at the link, I probably have moisture seeping into my attic, despite my efforts to seal leaks before I added insulation. I'll see if lowering the humidity indoors by not drying my clothes indoors and not running the humidifier help. I may remove my light fixtures and try filling any gaps that I can see around the junction boxes with expanding foam, though I'm not sure if that'll actually help.
"You need a little bit of insanity to do great things." ~ Henry Rollins

MDM

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Re: Moisture in the attic
« Reply #9 on: January 14, 2018, 06:15:31 PM »
I'll see if lowering the humidity indoors....
Do you have something similar to this Humidity Monitor?

Sun Hat

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Re: Moisture in the attic
« Reply #10 on: January 15, 2018, 05:57:15 AM »
Not yet, but that exact model is in my Amazon shopping cart! I was given a gift card for a local hardware store for Christmas, so I'll see if they can beat the price first.
"You need a little bit of insanity to do great things." ~ Henry Rollins

MrSal

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Re: Moisture in the attic
« Reply #11 on: January 15, 2018, 08:37:45 PM »
Quick question... Since I insulated my attic this fall I'm interested in this. Where would  condensation form in case there's any? Under roof deck? I have about 16-17" of cellulose and am trying to keep the attic under surveillance to make sure there are no condensation problems up there... With these temps should I look for ice formed under the roof deck?