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bakmorse 12-19-2010 11:54 AM

frost in attic
 
I will try to keep this as short as possible. Last January I went into my attic(not finished two story house) and I found dripping water and black mold all over my roof and soaking wet insulation. I called a mold remediation company to take care of that problem and I thought i fixed the moisture problem. Here is what i did, my soffit vents were non existent (blocked off by insulation, so i pulled insulation back, removed wet insulation, added 18 inches of roll insulation (now have 23 inches) (I dont think there was a vapor barrier beneath the old insulation), added ridge vent, added attic fan with thermostat and humidistat, recently put thermometer and hygrometer up there only to find the humidity level to be 85%, house RH @ 33% outside temp 21 attic temp 30 Just looked up there and i have frost on the roof again, and some slightly moist spots on my insulation. I'm wondering after reading other posts if the gable fan and vent are counter productive and negating the soffit and ridge vents. Now I am clueless. What else can i do?

Slyfox 12-19-2010 12:27 PM

Once you verify that you have proper ventilation and insulation,
http://app4.websitetonight.com/proje...s/14324189.png

inspect your roof to make sure it's not leaking.
Even a minor leak that is being hidden because the leak is low on the roof and leaking into your eave overhangs or in a valley in which may at times be hidden by additional structure boards, could still allow moisture into the attic and cause issues.

Once the above is found not to be an issue, you want to check all ceiling penetrations such as plumbing stacks, in set lighting, sky light fixtures, duct work, etc.
Anything penetrating the ceiling should be properly sealed so to not allow warmer air from the living space into the attic space.
Also make sure your bathroom & kitchen exhaust fans are not venting into the attic, they should be vented directly out of the home, via the roof, eaves or walls.

MJW 12-19-2010 12:41 PM

Quote:

Originally Posted by bakmorse (Post 553635)
I will try to keep this as short as possible. Last January I went into my attic(not finished two story house) and I found dripping water and black mold all over my roof and soaking wet insulation. I called a mold remediation company to take care of that problem and I thought i fixed the moisture problem. Here is what i did, my soffit vents were non existent (blocked off by insulation, so i pulled insulation back, removed wet insulation, added 18 inches of roll insulation (now have 23 inches) (I dont think there was a vapor barrier beneath the old insulation), added ridge vent, added attic fan with thermostat and humidistat, recently put thermometer and hygrometer up there only to find the humidity level to be 85%, house RH @ 33% outside temp 21 attic temp 30 Just looked up there and i have frost on the roof again, and some slightly moist spots on my insulation. I'm wondering after reading other posts if the gable fan and vent are counter productive and negating the soffit and ridge vents. Now I am clueless. What else can i do?

You are on the right track. :wink::thumbsup:

bakmorse 12-19-2010 12:48 PM

Thanks for the replys. I dont have any vents going into attic, I do have the furnace vent going through will check that for leaks. I have a whole house fan (have it sealed off) I was wondering if I should block off the west end gable vent and the east end attic fan? Thanks again for any help.

oh'mike 12-19-2010 04:02 PM

Make sure that the soffit vents are open and not blocked by insulation--You should be able to see light coming in at the soffits--

bakmorse 12-19-2010 04:55 PM

just blocked off gable vents and fan. there's plenty of light coming through soffits. just a waiting game now to see if humidity falls over the next couple of days. Thanks again.

oh'mike 12-19-2010 05:05 PM

Gable vents are famous for being under sized---Consider adding a ridge vent in the spring--and then blocking the gable vents so convection will pull from the soffits.

bakmorse 12-19-2010 05:31 PM

I have continuous ridge vent now, i think the gable fan and vent were screwing up the flow from soffit to ridge. Thanks Mike.

mjdonovan 12-20-2010 10:20 AM

Check Batroom Exhaust Fans, Vent Stacks and Roof Leaks
 
It sounds like you did all the right things in terms of fixing the attic ventilation and insulation. However, I'd go back and make sure your bathroom exhaust fans are being vented outside and not into your attic.

Also, make sure there is insulation tucked well around any vent stacks that may be coming up from the living area below. The holes associated with vent stacks can let a lot of warm moist air into the attic.

Finally, check the roof for leaks. I suspect you don't have a roof leak as you would probably see water coming down into the living area of your home, or at least forming wet spots on the drywall ceilings.

OldNBroken 12-20-2010 10:48 AM

Bakmorse, it sounds like you did your homework and you did the next thing I would have recommended. I'm guessing your gable vents were short-circuiting your ventilation.

Let us know how it turns out.

bakmorse 12-20-2010 07:50 PM

well, it has been 28 hours since sealing off gables, and wraping the furnace exaust stack elbows (didn't seem to be leaking but figured why not) dont see any leaks in roof, no other exaust coming into attic. Hygrometer reads 88% not looking good for the home team.

Jackofall1 12-20-2010 08:17 PM

You mentioned that you had a whole house ventilation fan, how well is that sealed off, sounds like the biggest opportunity.

bakmorse 12-20-2010 08:47 PM

sealed it off in the interior with a whole house fan cover, sealed it off in the attic with 1 inch insulated sheathing. and wrapped all edges with shurtape ductwork tape. Thanks

OldNBroken 12-20-2010 09:10 PM

meter broken? :whistling2: :whistling2:
sorry, just had to throw that in.

I just noticed something you never mentioned. Do you have a barometer? Are you still getting the dripping condensation you were experiencing before?

MJW 12-20-2010 09:25 PM

I think you may want to add some bath fans and a fan in the kitchen. With no fans to move moisture out and no vapor barrier, the attic is getting a ton of moisture pumped into it.

What is the situation with the roof? One layer? Two? I&W shield? how much? Is it shingles or tin?
Is the attic fan coming on? Doesn't that seem to help?


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