I am finishing our third floor and will be hiring someone to install the vent caps in the roof for a secondary plumbing stack and for two air vents (for a range vent fan and a bathroom vent fan). Our house is 130 years old and has seven steep gables. There is a trap door (sealed shut) two-thirds of the way to the top of a gable, which is elevated from the shingles and covered with some kind of a membrane, that I would like to have the vents go through, rather than cutting a hole through the shingled part. (The roof was replaced three years ago.)
Here’s the thing. I want to know what I’m talking about when I hire someone so they can’t take advantage of us. I’m not getting up on that roof to inspect their work, but my husband (who has no building experience) will be taking video and pictures with his drone.
What kind of vent caps should we buy? What material should the plumbing vent be? (Inside the house it will be 2" schedule 40 ABS, but I have read that ABS isn’t good for the exterior. We live in Iowa, so our temperature ranges from over 100 F in the summer to -20 F in the winter.) And what about flashing? (BTW, the trap door is at the same pitch as the gable, just elevated from it.)
Thank you in advance for any and all input!