Hi, I have an open beam house (no attic access) built in 1962. I live in cold, dry Edmonton Alberta. My low slope roof doesn't leak, however about once a year in the spring when we have a big temperature increase, I get water dripping from my interior open beam. Only lasts a few hours, I understand that my vapour barrier is compromised, and this is a result of accumulated moisture thawing. I'm reluctant to replace a perfectly good roof until I need to. It is a rubberized ashalpt membrane. Is there any other option available to me?