Our bungalow has been experiencing water dripping down the side of the toilet vent stack and making its way to the basement floor. The quantity fluctuates from an ounce a day throughout the winter months to a flood of water pouring through the bathroom fan and lights on the main level during the spring thaw. There have been a number of remedial attempts by the builder but none have rectified the problem to date. I have seen up to 2 inches of snow in patches directly under the roof vents. This would result in insulation between 2 vapor barriers at 4 spots.
Answer:
If snow is accumulating in the attic due to a problem with the roof vent, its the wrong kind of vent to be using in that situation. Two vapour barriers is always a problem and you don't have to go to that much trouble. Properly installed insulation and vents will avoid all of that. There is no reason for condensation to be there and when someone who specializes in insulation, ventilation and roofs visits the site, you'll have an answer in a heart beat.
