Need to correct moisture/mold problem on cathedral roof
Have a room over garage center with closets on both sides between the closet kneewalls and the eaves. Insulation over the room section is 6 inches of foam slabs sealed by “Great Stuff” spray-in foam. Above this ceiling foam and under the roof plywood, there are 1 inch x 20.5 inch unobstructed foam encased ducts between the rafters for venting to the roof peak vent. The side sections outside the knee walls are insulated with rolled fiberglass fiber with durovent ducts above the insulation. There are substantial soffit vents at the bases of the durovent ducts. After a new roof was installed, the fiberglass started to absorb substantial moisture and mold appeared on the plywood as shown in the picture. This only happened on the north side of the garage, none on the south side. Since the plywood must now be removed, I am thinking of increasing the duct heights by raising the roof to give 2 ” ducts rather than the 1″. Also I would add a mid-roof SmartVent to increase airflow. In addition I would increase the peak vent height from a Coravent 300 to CoraVent 600 to double the outlet area. Does this look like a reasonable fix?