#7190423 - 12/16/12 10:47 AM
Ice in attic
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Campfire Guide
Registered: 02/19/01
Posts: 2951
Loc: Eagle River Alaska
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Had a energy audit and found ice in attic where I did not have soffit vents. Spent a miserable day putting in soffit vents and
insulation baffles in the attic. In one day most of the ice was gone.
Have soffit vents and gable vents with ridge vent. Have
heard where having both soffit and gable vents creates short ciruiting. So closed off gable vents. What are others doing
in AK to prevent roof issues?
_________________________
kk alaska
Alaska 7 months of winter then 5 months of tourists
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#7190503 - 12/16/12 11:01 AM
Re: Ice in attic
[Re: kk alaska]
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Member
Registered: 12/20/11
Posts: 77
Loc: Alaska
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The house I am in did not have any venting last year and there were moisture problems. Gable vents were put in this summer and so far things are good. The reason given out here for no venting was the constant winds. I do believe a house has to breath somehow or problems will devolop.
The house I have back in northen Michigan has both soffit, gable, and ridge venting and I had no moisture problems
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#7190757 - 12/16/12 12:06 PM
Re: Ice in attic
[Re: Unalakleet_Yooper]
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Member
Registered: 01/25/08
Posts: 172
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Another source of ice in the attic is caused by attic bypasses. This is where hot air is allowed to escape the conditioned air envelope of your heated space. The large amount of air cannot be dipersed by the attic venting. Examples of attic bypasses include gaps in the vapor barrier around electricle boxes for ceiling fixtures, gaps around plumbing vents and soffits over cabinets or showers. I had a huge bypass over the soffit in a bathroom shower. The dumbazzes that sheetrocked did not put any rock over the top of the soffit. Then the dumbazzes that insulated merely stretched vapor barrier over the top of the soffit and blew in insulation. Staples and plastic did not support the weight of the insulation. I had an impressive pillar of ice that stretched from bathroom ceiling to the roof. Also, make sure your exhaust fans are vented through the roof and the piping is air tight.
Edited by bobmn (12/16/12 12:07 PM)
Edit Reason: spelling
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#7190807 - 12/16/12 12:22 PM
Re: Ice in attic
[Re: bobmn]
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Campfire Tracker
Registered: 09/10/09
Posts: 6346
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Another source of ice in the attic is caused by attic bypasses. This is where hot air is allowed to escape the conditioned air envelope of your heated space. The large amount of air cannot be dipersed by the attic venting. Examples of attic bypasses include gaps in the vapor barrier around electricle boxes for ceiling fixtures, gaps around plumbing vents and soffits over cabinets or showers. I had a huge bypass over the soffit in a bathroom shower. The dumbazzes that sheetrocked did not put any rock over the top of the soffit. Then the dumbazzes that insulated merely stretched vapor barrier over the top of the soffit and blew in insulation. Staples and plastic did not support the weight of the insulation. I had an impressive pillar of ice that stretched from bathroom ceiling to the roof. Also, make sure your exhaust fans are vented through the roof and the piping is air tight. Yes, this is the most current building science, in my opinion. I'd reccommend stapling 6mil plastic sheeting to all ceilings of new construction, then nailing 1x4's over the sheeting to have something to screw the drywall to. Nail the ceiling boxes to horizontal 2x4 blocking and seal the hole for the wire with expanding foam. This helps minimize the "stack effect" in a home.
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#7196967 - 12/17/12 07:24 PM
Re: Ice in attic
[Re: colorado]
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Campfire Ranger
Registered: 12/10/04
Posts: 1937
Loc: Southern New England
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Another cause of improper ventilation is covering the soffit vents with insullation. Many believe the more the better but you need the attic to "breath". Between the siffit, ridge and gable vent you should have more then enough ventilation in the attic.
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#7197502 - 12/17/12 10:16 PM
Re: Ice in attic
[Re: kk alaska]
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Campfire 'Bwana
Registered: 01/28/01
Posts: 12856
Loc: Burns/Hines, Oregon, USA
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A local motel here was built with the swimming pool space vented solely into the attic space. Can we say collapsed roof and ceiling the first winter.
Edited by 1minute (12/17/12 10:17 PM)
_________________________
1Minute
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#7197514 - 12/17/12 10:34 PM
Re: Ice in attic
[Re: kk alaska]
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Campfire Tracker
Registered: 09/10/09
Posts: 6346
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Probably the best way to build for a cold climate is to eliminate the attic entirely and have a vented cold roof. IE, this can be done with 4-6in of polyiso or DOW board on top of a T&G board ceiling. Then nail sleepers with pole barn nails to the ceiling beams/purlins. This space only is vented from the soffit to the attic. Classic Post & Beam in NY used this method and it had held up well
A slightly more expensive, but less labor intensive method to achieve this would be to simply use stress-skin panels and install the sleepers on top of them and deck and shingle/roof.
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