Mold on Soffits
Alright mold sleuths, here’s one for you:
I have two sheds, which for practical purposes are identical – except one is insulated and heated, and the other isn’t. The roofs differ in that the tool shed has a single layer of 1/2″ exterior grade plywood as its decking, which is visible from the underside. The she-shed has the same plywood layer insulated with EPS over the heated area, and outside that a 2″ void at the overhangs. Above that is another layer of plywood as the roof substrate. The insulated shed grows a coating of light green mold on the surface of the soffits, the tool shed never does.
A bit of context:
The insulated roof is well air-sealed.
This is in the easy to grow mold PNW climate.
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