Mold due to condensation
We needed to insulate in the fall before we had completed electrical in order to not lose the winter as building time on our cottage project. Since the insulation has been in place since December and we heated the building we predictably developed mold on the back face of the sheathing. It was only here and there 3-4 weeks back, but it’s pretty well most cavities now.
What steps should I take to remediate? I was planning on removing the insulation, and spraying with something like concrobium mold spray, waiting for the insulation and sheathing to feel dry and reinstalling and immediately putting up the vapour barrier. Do we need to scrub? If yes, any ideas on maintaining air quality? Any recommendations on mold sprays?
I figure as temperatures get closer to being equal inside and out it will make this all go faster.
Any other thoughts or concerns?
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Replies
You don't usually need to scrub the non-fuzzy stuff. The gray/black areas you might need to scrub, the fuzzy part are the "fruiting bodies" of the mold, which is where the mold spores come from. You don't want to breathe the dust from those. Apply the mold killing stuff FIRST. Wipe/scrub stuff while it's WET with the mold killing stuff so that you don't have dust coming off.
Another option is to just paint over the stuff with mold killing primer (Zinsser makes one I like to use, but there are others). I usually apply the mold killing stuff, let it dry, apply a second time, let it dry, then go over the area with a coat or two of mold killing primer. The mold killing primer kills the mold AND prevents regrowth AND encapsulates whatever is left behind on the wood. It's not even very expensive to buy the stuff.
For light mold I usually just bleach and wipe the stuff off with a paper towel, but heavier stuff I like to follow up with the mold killing primer. I also use the mold killing primer anytime I suspect the mold might come back again, which means I almost always use it in attics, but sometimes also in areas of exterior walls where I think conditions might ocassionally allow for mold growth. It doesn't hurt to be extra careful.
Bill
The info on Zinsser's site for that paint says that it's for use on non-porous surfaces.
If you read through the datasheet, it says it's good for wall cavities and wood moulding too. It works fine on things like plywood and framing lumber, which is where I've used it many times in the past. I'm sure it's fine on OSB too, although I've never tried that.
Bill