We have a cabin with sopping wet insulation in the valuted ceiling/roof. We found out the sheathing needs to be replaced -- no visible damage to drywall, yet. However, I am wondering what you have to say about the insulation chutes (plastic)that one uses between the sheathing and the new insulation. We have to tear off the roof and replace the insulation and sheathing (and shingles). Very expensive. In your opinion, was this due to condensation, not enough air ventilation? We have a roof ridge vent and round vents in the soffit. No water damage is visible on any of the ceilings. Thank you for your advice.