: Two second floor bathroom fans exhaust to a stack that runs up thru the roof. The builder used PVC pipe (4"?) from the fans to a "T" and then to the stack. I have always seen flexible exhaust hose in these applications. Is the PVC OK? BTW, I have wrapped insulation around them to prevent condensation when the warm, humid air reaches ambient temperatures in the attic.
PVC pipe is fine for the exhaust. It is more expensive to install than the flexible hose, and takes more labor to install as well. The builder probably wants to consider his houses better built. What kind of plumbing fixtures did he use?