Ah yes. Well I went to my local contractor about that question when it came to the Retrofit here.
The old plumbing vented through the center of the flat roof of the trai- er, um Prefabricated home (
) which lead to a series of leaks along the pipe, undetected for years which lead to more issues as the supporting structure for the galvanized pipe rotted away, letting that vent pipe sink, causing connecting pipes to leak inside the wet wall (common wall between the kitchen and bathroom) Which was the reason why I had to do a retrofit in the first place.
That's history.
Part of the retrofit here was to remove as many holes in the roof as possible. We removed the old a/c unit, we removed the old stove vent (another hole in the center of the roof which leaked). Both were replaced with through the wall vents. Since the plumbing vent was the culprit which lead to a costly retrofit, I desired to remove this as a possible future issue by extending the pipe through the exterior wall up along side the wall to vent.
I too was uncertain about the plumbing vent so I asked. Here (in my county) it is code to vent through a wall as long as the exterior vent pipe extends (at least) 8 inches above the roof. Not the peak, but where ever it comes above the roof.
The Trailer does not have an over hang of the roof having the roof stop where the wall begins. However the contractor I spoke to did tell me that I could use elbows to angle the vent pipe like a gutter pipe, with an angle which would allow possible drainage, around the overhang.
Sorry I do not have the code number. I do not know if this is Universal Building Code or just local. I do not even know if this has changed since the retrofit was done.
I would suggest calling the Building inspector (local) and ask them specifically what te code says in your location.
David
