I bought a six year old house last Feb. It is in the Seattle-type wet west coast climate zone.
Today I checked the attic more thoroughly. The roofing looks good. No evidence of ever having a problem.
Yet there is a lot of condensation dots obviously once moldy along the inside of the roof and the south wall. This is obviously coming from moist air in the living area in the coldest months. Right now the dots are dry remnants of the cold weather problem.
But I have no reference point.....how much is too much? For six years, it looks not bad, but is any evidence of moldy condensation too much?
The only ventilation is the usual along the soffit via styrofoam channel and at the ridge.
About half the houses in the neighbourhood have additional vents with wind turbines. Should I get one put on? Do I have to go through some volume calculation first or is it just a good idea in any case?
I'm not a mold expert, but I'd say _any_ mold is too much mold. If there was a spot or two, and it could be traced to an old problem that had been fixed I'd say they just didn't clean it up. But if you see nothing obviously wrong (no sign of a repair or leak) then the install may not have been done well in the first place. Are the soffit vents clear? Can you tell if they are actually functioning? Looking from the outside, how many soffit vents are there? Styrofoam may be there inside, but siding may have covered all the vents.