Frost in attic

mulherin31 · 02-10-2011, 05:11 PM

Hi guys,

I am a new homeowner and recently had insulation blown into my attic at the rate of R40. There seems to be a small amount of frost near the bottom of my attic roof, towards where the soffits/sheathing may be. Should I be concerned by this? What may be causing this? I installed a few small soffit vents back in September, but I'm worried there still might not be enough air flow. Any suggestions/help would be greatly appreciated.

Thanks!

**oh'mike** · 02-10-2011, 05:23 PM

Yes you should be worried----Did you put baffles into the soffits before the insulation was blown in?

You should be able to stand in your attic with the lights off and see light coming in through the soffits.

You might want to install full louvered soffit covers if your house can use them.

The damage to your house can be substantial----find the cause and fix it --pronto.---Mike--

mulherin31 · 02-10-2011, 09:16 PM

Thanks Mike, Baffles were installed in the soffit vents. Also, the only area I have seen is over the garage which is opened and closed quite frequently.

We recently had an ice storm here in Indy and there is pretty substantial amount of ice on the roof and in the gutters. Could this be a cause for the frost or is it air flow???

Thanks!

**Gary in WA** · 02-10-2011, 10:35 PM

The ice dams are from heated air leaks to the attic from living spaces below. Many times ineffective wall insulation will have convective loops that deposit the heat to the top plates which have minimal insulation between them and the roof structure. Wire holes, etc. let air from below into the attic combined with lacking ventilation of the attic = ice dams; http://www.buildingscience.com/docum...d-135-ice-dams Did you completely air seal the attic before adding the insulation? http://www.google.com/url?sa=t&sourc...O842EQ&cad=rja

You need a balanced attic venting system, just adding more may not solve your problem. On the other hand, how much attic venting do you have? Number, size of intake (soffit) vents, number, type of exhaust vents, powered, static, etc.

Gary

SuperHans · 02-10-2011, 11:13 PM

Does the frost run the whole perimeter of the attic, or just certain areas? Somehow moisture is infiltrating your attic. Take a look and see where your dryer vent, bathroom fan, etc. are venting and try to pinpoint where the water is creeping in.