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checked attic insulation & found mold

mik's Avatar

Join Date: Jul 2003
Posts: 224

12-16-11, 06:54 AM   #1  
checked attic insulation & found mold

We live in the northeast & have owned our stick-built colonial for 4 years and I just climbed up into our attic to check the amount of insulation there, and I think that the builder may have installed a minimum amount- they installed rolled fiberglass bat insulation (paper side down towards the living area) at a general thickness of about 12 inches. But while I was up there I found black mold growing on the inside of the roof sheathing. It covers the lower area between 3 separate bays between the studs/joists and climbs up almost to the roof at one point...it covers about 30 square ft. Looking further, I see that the builder ran the exhaust duct from the bathroom ceiling fan under the insulation & directly to the soffit right in that exact area, and then they seemingly just left the duct pointed down towards the soffit. Instead of blowing out the soffit, the moist bathroom fan exhaust air has apparently just blown back up along the interior roof for years, causing the mold. At this point, I just want to fix the problem & don't care about who's fault it is. (house it 11 years old & builder has passed away anyway) Do I need to hire mold mitigation specialists ($$thousands$$) or is there a way to treat the mold myself?
And I assume that we should hire someone to reroute the bathroom fan- shouldn't it be properly run to the outside wall of the house & exhausted through a louvered vent? It seems that this would eliminate the source of the mold. The duct is a pliable plastic material and not rigid. Plus we have our master bath ceiling fan that is probably run the same way- couldn't get all the way over to that one.
THEN maybe we can get to the point of having some blown-in insulation added to the attic.

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Bud9051's Avatar

Join Date: Oct 2008
Posts: 9,764

12-16-11, 08:45 AM   #2  
Sounds like you have a good handle on the problem. If the mold is really well established you might need a pro, but eliminating the moisture source should stop any progress and perhaps you could wait and see. At least comes spring it would be an easier task to evaluate the task.

Run those bath and kitchen exhaust to a side wall or up through the roof. I don't like the soffit vent versions as the warm air is still drawn right back into the attic. AS for tossing the flex into the soffit, that is dishonest, which means worse than stupid.

Have them use rigid duct and not the flex and it must be well insulated. I've seen cups of stagnet condensation laying in poorly insulated ducts, ehk!

Not sure on the insulation description, but before you add anything, you will want to air seal everywhere you can. A lot easier than digging through another 12 inches of new stuff.


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