I have a flat roof on the back part of my house. Last year I had a new roof installed. They used a rubber type of roofing that needs to be heated when installed. Soon after the roof was complete we noticed some moisture in the one room upstairs, at the time the drywall had been pulled down and the rafter was all exposed. It seemed as though it got worse as the weather got colder. At one point it seemed like a rain forest up there, no rain outside but plenty inside. The roofer came back checked for any loose seams and such and said he had really never seen anything happen like this but had spoken to some other roofers and they all agreed that it was probably because there was no air flow at the rafters, no insulation, and no heat upstairs causing the condensation build up. In the spring it all seemed to dry up and we proceeded to put up insulation, leaving room for air to flow and drywall. There has also been heat added. The problem is that as the weather has gotten colder I noticed the seam on the drywall seperating and when I touched it to see why, much to my surprise water came out. The drywall is all soaked and no one seems to know what the cause is other then an air flow problem. I have lived in the house for 28 yrs and never had this problem before and haven't changed anything. We added a ridge vent and made the soffits all vented to try to help and it hasn't helped. Please help before the drywall falls down again.
Thank you for your time