My shower wall is 2x6 studs, I would like to put a vent in the tile wall leading to the floor joists, (which will collect and vent through the foundation apron exiting a surroud in the joist cavity) using 3" plastic tubes in the rough in... I cannot find a suitable 90 degree elbow in either PVC or composites that are built to slip fit correctly. I am open to suggestions or retailers site providing parts to do this. I have designed a cobbled idea using Sanitary PVC and a 4" patio drain flange, at best a poor substitute. I believe having the tubes in the heated part of the house until exiting at the vent outlet would limit condensation caused in the cold attic, and gravity would help any moisture "descend" to a lineal basin enclosing the fan and tubes. Instead of pushing it upwards. There it could be tapped to a drain, unless the basin would air dry. I digress: Help? rd