I have been asked to find the cause, and repair a moisture related problem on a double wide mobile home roof.

The problem is this: the mobile home is 18 years old, and has an asphalt shingle roof. The roof pitch is fairly low, maybe a 3 in 12. The mid section of the home is a cathedral ceiling, and this is where the existing problem is at.

Two years ago, the roof was replaced. The roofers did a horrible job, and last year I had to replace the roof again. Many structural repairs were made. One of the repairs that was done was to replace the rotten, falling off the house fascia boards (hardboard of all things). I used cementious soffit/fascia material for this application. I sealed back up the soffit and fascia area just like it had been for the previous 16 years.

Approximately 6 months AFTER the new shingles were installed, the cathedral ceiling area has developed a few small wet spots on the ceiling panels. Now, two weeks later, and absolutely NO rain, the spots are getting bigger, and spreading. I am pretty sure that condensation is the culprit, but why now, and not 6 months ago?

The ceiling has a vapor barrier, and blown in celluslose insulation. All original from the manufacturer. Each cubby hole of the cathedral ceiling is sealed up tight, and has always been that way except for the brief time that the fascia and soffit boards had rotted off.

What can I do to stop the moisture problem? Any way to vent the cathedral ceiling from the outside (fascia/soffit area) that is effective?

Really need some help here.