Can you coat your vents and drains with TPO or PVC?
What is the difference between the Ex-flow and M-105 vents?

The new drain you sent me home with worked perfectly and even though I wasn't a seasoned roofer, I was still able to put it in in six minutes.  Thank everyone that helped me, you guys were a tremendous help and looking forward to doing business with you and your company soon. 

— Brian, Maintenance, Buffalo, NY