Plumbing penetration through the roof - how high is too high?
Looking up at the rear roof of this new construction I saw the plumbing penetration was very high.
This particular tubing was 27" high.
Is that too high?
The usual height above a roof is the 10" to 12" range.
But that depends on the local area, climate and rules. Some jurisdictions want particular lengths to accommodate for frequent, deep snow falls.
It's also made of PVC tubing.
While there is the general thought out there that PVC is degraded by sunlight and UV rays, I have never seen evidence of it.
Some builders will paint the tubing with black latex paint, or use ABS tubing, which is a black plastic. But I seldom see ABS tubing penetrate roofs.
However, what problems can happen if the plumbing penetration is too high?
1. It can freeze inside, and clog. While I have heard that, in this area I have never seen it happen. But I have read where it happens further to the north.
2. It becomes wind vulnerable and can be deflected and move. That can loosen the rubber collar at the roof line, and cause cracking or leaks. Plus, the older the rubber collar gets the more brittle it becomes and therefore more prone to cracking. So movement from high winds could be even more damaging.
The fix here is simple - cut the tubing back to the 12" height and be done with it.
My recommendation: home inspectors need to have forethought when investigating houses. Placement of trees, shrubs, dryer vents, how shingles are placed and cut, and even the height of plumbing penetrations need to be looked at in the context of time. Why not forestall the aging or potential damage of anything by handling it properly at the outset? I can tell you that comments on inspection reports about "minutia" like plumbing penetration height will bother a builder to no end. But over time the client is benefited, and in my opinion the client rules.
Jay Markanich Real Estate Inspections, LLC
Based in Bristow, serving all of Northern Virginia.
Office (703) 330-6388 Cell (703) 585-7560