Vents through roof

[Ernie Starnes]

I recently had to replace some of the rubber part of the roof jacks on some of the vents going through my roof. This is on a 12/12 pitch roof and the boot is really straining to make the 45 degree angle. It made me wonder why plumbing vents always run vertically through the roof. Why not run them perpendicular to the plane of the roof?

Are there code requirements to have them vertical?

 

[Breplum]

Yes code does dictate but your thought is very smart.
Also, you likely have standard roof jacks but they make (w/o the rubber collar) jacks for 12/12.
So, you have the wrong flashing to start with. Sorry