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waldzinator 02-12-2013 12:04 PM

Attic Mold, Venting, and Insulation

I'm going to be pretty thorough here, as I want to solve this once and for all. I have a 1930 tudor style house here in western PA. We've had the house for coming up on 4 years. We have always had an issue with icicles on the NE facing side of my house. We have also always had frost on the inside attic boards and nailheads, mostly concentrated along NE side. I should note that this is the side of my attic that sits about the stairway that leads to the 2nd floor (it's a full, walkup attic). I should also note that the attic door is directly across from the 2nd floor bathroom door.

After replacing the roof on our house Fall 2011, I decided to beef up the insulation in the attic. It had just blown-in cellulose that had settled a bit. I layed unfaced R-19 batts in between the joists to bring it up to the top of the joists. I made sure to use baffles in between the rafters. On the NE side, I also ran some faced R-30 batts on top of the baffles up about 48 inches. A month later, I found it saturated behind the baffles and mold all over the NE side. I ripped down the baffles on that side and the insulation. that spring, I cleaned the mold with Foster 40-80. Well, this winter, the mold came back. Same dampness on boards and frost on nails.

I checked and my bathroom fan vents outside. I added some rigid foam to the handle side of the attic door to prevent updraft of warm, moist air. I'm at a loss. The house has a hip roof, attic does have a ridge vent and soffit vents...not continuous, but every so often. I'm not sure if they are plugged with old cellulose or not. I want to make this spring the LAST time I have to deal with the mold, frost, and moisture. HELP PLEASE!!!

cibula11 02-12-2013 01:46 PM

Do you have vents in the roof? If so, how many?
Is there venting in the soffit?
Could the dryer be vented into the space?
Do you know if there is a vapor barrier below the insulation?

waldzinator 02-12-2013 02:03 PM


Originally Posted by cibula11 (Post 1115850)
Do you have vents in the roof? If so, how many?
Is there venting in the soffit?
Could the dryer be vented into the space?
Do you know if there is a vapor barrier below the insulation?

There is a ridge vent and there are soffit vents. As I said, the soffit vents are noncontinuous...they are spaced out ever few feet. Dryer is not vented into the attic. I cannot 100% say that there is a vapor barrier or not beneath the blown in, but I don't believe there is.

cibula11 02-12-2013 02:14 PM

It's possible if you don't have vapor barrier that the home's warm, moist air is coming through into the attic space....which is somewhat normal. This is why a vented space is needed to take that air outside.

My house had similar issues, especially on the north facing side. I discovered that on first glance, there were soffit vents, but whoever sided the house continued it all the way to the underneath part of the roof, essentially sealing off any air flow. I'd first check the soffits to see if they are clear. If they are, it may be best to call in the pros.

Do you know if there is any venting currently ran through your attic space? Maybe a leak or crack in the vent...Is there a furnace or other mechanicals present?

waldzinator 02-12-2013 02:20 PM

Nothing currently vents into the attic. The only thing running up there is the bathroom vent fan. I double checked and the exhaust duct does run outside. The other thing that runs up into the attic is the ductwork, which then splits off into the individual ducts going to the various bedrooms below. The ducts are wrapped in insulative wrapping.

bobinphx 02-12-2013 02:47 PM

mold bad, rust bad.

with that said, what does mold need to survive. Warm and moist conditions. What does rust need to grow. moist conditions. where does warm and moist come from. warm from inside the house, moist from either inside (people, showers, laundry, etc) or outside (roof leaks, high humidity air, snow blowing in,,,etc)...

built in 1930. I would also suspect lots of remodels over the years and maybe a few suprises in the walls, ceilings and under the insulation.

If it were mine (and remember I am a thousand miles away) I would think about pulling all the old isulation out of the attic (all of it, every last bit!!). I would then seal the drywall (or in your case plaster and lath) at any and all penetrations (light boxes, plumbing stacks, cracks, all joist to ceiling connections etc) and then put in a good solid vapor barrier as well, then put all new insulation in. I would also then calculate the current open vent area of your entire attic and if it was below hud minimums for your area, I would add more soffit vents (lots more!!).

boat load of work... but it can be done..,. The other alternative is to have spray foam put in on the floor of the attic. Spray foam does a great job of stopping air leaks, but it sure is expensive!!! or you could always move!!! LOL

just some thoughts to start your wheels turning.

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