moisture on vapour barrier
I am working on a 1960's add-on to an old church. There is moisture dripping down the inside of the plastic vapour barrier (only on this one wall which gets a good amount of sun on it). I have cut some gyproc out and see that the gyproc is fine - no signs of any wetness. I have removed some of the rear shingles and these have tar paper behind them and the wood appears fine behind the tar paper. The roofing shingles are 2 years old and I can not understand why this should be happening. There are no windows in that wall. The shingles had been latex painted on that wall last year and I now see that they had not been prepped properly and that there are some paint bubbles with water in them so this will have to be scraped and painted again. Anyone know why this wall isn't staying dry and what I can now do about it. Many thanks.