R & R insulation - mold!


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Old 02-19-20, 09:36 AM
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R & R insulation - mold!

Hello - short version of story - Son bought 1924 1-1/2 story house which had been attic ventiation blown shut (but still had gable vents). Roof was leaking, PO had humidifier going. Inspection report said ' a little mold present' - ha, see picture.

I checked it out as soon as possible (was 1st day of spring thaw, so worst case for condensation).

Fast fwd, we have pulled out enough insulation to get airflow soffits to peak.

New roof scheduled next month. Roof will be re-sheathed with furring spacers, leaving old T&G plank sheathing in place. Rafters are 2x4, 24' OC - roofer does not want to remove old sheathing, said it would then be too weak. Will have roofer spray concrobium on top side of sheathing.

We are going to completely vac out the blown insulation & start over. After removal, spray several doses of concrobium. Then foam seal all the air paths coming into the attic that we can find. Also suspect the original furnace flue path still there, buried. So am thinking the mold had several causes.

Now is where I would like some feedback. We are thinking of re-insulating with blown in fiberglass. The inside wall is old school lath & plaster, very rough inside the cavity. Since the top side of cavity will still be the old planked sheathing (with some good sized air cracks to air gap under new sheathing), we think the packed cavities will stay dry. But do we need to put some air barrier to prevent wind infiltration into the fiberglass? Not planning on adding a vapor barrier against inside wall.

Thanks for any advice.



 
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Old 05-10-20, 03:42 AM
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Update - We got the roof replaced with entire new deck sheathing. The new sheathing is spaced 3/4 inch above old sheathing, which they largely left in place.

We rented an insulation vacuum & removed all of the old insulation, which was pretty smelly.

Next is to seal the air leaks, then reinsulate.
 
 

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