Latest Discussions : Roofing & Siding

BV013229

09:06AM | 10/28/16
Hi!
I've been at battle with my house's attic for a while now. I have a mid 80's cedar house that when I first moved here didn't have any soffit vents and only a few mushroom vents and a powered vent. Very little insulation as well. A few years back we had frost on the bottom of the roof so bad that when the sun came out it caused the frost to melt and drip. I found that when that happened the attic fan motor had burned up and wasn't exhausting the humidity. So I decided to redo things. I moved all the insulation to one side of the attic, boxed in any areas that were open (such as above stairs and showers) did spray foam for any openings like conduit, tops of walls, etc. I cut in soffit vents and put in baffles (used two in each stud run) and then I put down new rolled insulation one direction, again another direction, and then throw the little blown in that was originally there on top of the rolled down. What I've noticed (I have a meter in the attic) is that in the mornings early before anyone is up and about, my attic fan will run due to high humidity (it's running now at 7am with a humidity of 83%). I have vented the bathroom vents to the outside of the roof with proper vents, I don't have a humidifier running in house, nobody has showered this morning yet. I thought perhaps the cold air in the attic (it's around 42F out this morning) and the sunrise was doing it creating condensation but the fan was on before the sunrise this morning. Last week I went as far as cutting in a ridge vent to further assist with exhausting. The fan still runs. I'm at a loss at how to get this humidity out and how to be done once and for all with attic ventilation worries...
Thanks for any help,
Matt

BV011721

10:23AM | 11/01/16
It sounds like the conditioned air in your house is leaky into the attic. The warm air leaking into the attic has a higher RH than the attic and can cause the increase in moisture in the attic. It is a difficult job, but I would look for penetrations from the house into the attic. A blower door test will aid you in finding leaks into the attic.


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