I live in a one story house with an unfinished attic. Currently, the bathroom fan is vented by a 3" PVC duct that passes through the attic and out the roof. The attic gets cold (blown in rock-wool insulation lays between the foor joists) and the humid air being vented from the bathroom condenses. Unfortunately, the PVC is sloped the wrong way so condensate is dripping back through the fan and into the bathroom. Messy, and damage to the bathroom ceiling is occurring.
I'm planning to replace the fan with a quieter one with more volume, and I'd really like to avoid having to put another hole in the roof, and I also don't want to use the present ducting.
A builder who helped with some other renovations has told me that it's ok to run the fan exhaust duct (it'll be 4" diam) up to just beneath the ridge vent, and to allow the exhaust to vent through the ridge vent. Is this likely to work, and is it an acceptable way of venting? I wonder about blowback and about iceing during the winter.
Also, is it reasonable to insulate the exhaust ducting to minimize condensation within it?
Thanks for any comments or suggestions.
Bill Christens-Barry