I have a feeling I know the answer to my query but I have to ask to be sure. My home is a quad level (tri-level with a full basement) when I was up in the attic over the weekend checking out insulation levels I noticed that on the underside of the north facing roof I had some condensation dripping off the roofing nails. The insulation below this area was damp. The roof is a hip and the east, south and west sides were dry. The only vents in the roof in this area are two, yes I said two, turtle type roof vents on the south side of the roof close to the peak. The soffits on the home have vents every 5ft. Or so that are 4x6 or 4x8 vents. I think there's just not enough airflow with the two turtle vents on the south side of the roof, do you think it's possible to add a ridge vent to help increase ventilation :confused: This attic area is over the master bedroom and two other smaller bedrooms and two full baths. I would be guessing that the area is something around 40x30 ft. Also, why would only one side of the hip have the moisture? I can see why the west side wouldn't as it sits over the rest of the home. Sorry for the long winded question :D

My guess is that even through the snow, the other sides of the roof pick up enough heat from the sun to dry up the condensation. The water vapor then migrates to the cooler North side.

The sheathing on my roof mildewed after I tightened up and resided my house 20 years ago. I added ventilation and put a moisture barrier paint on part of the ceiling. I added ridge vents the entire length of it, and perforated aluminum the whole length on the North side.

If it is a newly build house, you might lean on the builder to make it right. Otherwise, adding the ridge vents isn't that bad of a job. Strip off the ridge cap shingles. Buy a cheap, disposable blade for a circular hand saw. Set the depth for just enough to go through the shingles and sheathing, and make cuts on both sides where the vents will just cover them. Rip off the narrow strips and nail on the vents. I used the metal ones meant to show. If you can match the shingles, you shingle over the plastic ones.

You might set a fan in the attic to stir up the air to get by the winter. Not a fun time to be up on a roof in Michigan.