Moisture/mold behind Intello membrane in tiny house
Hi everyone and thanks in advance for your expertise and advice.
I have been working on finishing a tiny house over the last several years. I know that this in itself is not ideal; it’s more or less a weekend project and therefore takes a while to progress between steps. I am no expert and figuring everything out as I go along.
Anyway, I purchased the building as an OSB shell on a trailer frame with a metal roof, so do not entirely know the details of the roof assembly. It appears to be sheathing with tarpaper over it, then corrugated metal. There’s a slight gap between the metal sheets along the ridge, where the tarpaper shows, and this is covered by a ridge cap. Under the edges of the ridge cap, there are strips of foam that fill the corrugations, and this same foam is at the bottom edge of the corrugated metal.
Inside, I added strips of expanded polystyrene foam along all 2x4s including the rafters, and added 1×3 strapping as nailers (this to break thermal bridging). I insulated with sheep’s wool batts, and installed Intello Plus membrane. I have a Panasonic ERV to pull moisture out of the air but haven’t installed it yet…dun dun dun.
Over the last couple of months I’ve been working on the drywall and was just starting the ceiling (tongue and groove boards). Here in New Hampshire it’s been super rainy and off-and-on humid. I noticed very recently that there seems to be staining on the Intello on the ceiling. I cut into it in a couple spots, and it feels humid up in the insulation and there are some moldy looking spots on the wool as well as the wood strapping. A photo of under the ridge cap and staining inside is attached (format/size due to 3mb limit).
What are my options? My thoughts are to:
-Replace roofing screws just in case the seals are bad and water is entering from above;
-Cut the tarpaper at the ridge and vent it somehow? Any help bringing that idea to life?
-Pull the Intello down and inspect the ceiling, removing bits of stained insulation and spraying down wood and wool surfaces with mold killer;
-Get the ERV installed asap.
Any thoughts and advice (please be gentle) would be most appreciated. Thank you!!!
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