We have been asked to diagnose a condensation problem on a gyp bd ceiling in a bonus room above a garage. The garage roof is a cross gable roof with ridge vents only, and little opportunity for cross ventalation. The garage is a large three car garage located at the water’s edge on Lake Toxaway in the mountains of South West NC, one of only two temperate rainforest areas in the world. The roof is framed with conventional framing lumber. The condensation is a primarly summer occurance.

The owner believes he has a roof ventalation problem. I am not so sure. Could it be an interior humidity problem?