12 ft horizontal vent pipe in attic for toilet?

[3h4life]

Hi, I have a 1-story, 2 bathroom home where originally my master bathroom and guest bathroom toilets were facing back to back with a shared double sanitary tee connection and 2" vertical vent pipe to the roof.

Now I have relocated my master bathroom toilet approximately 12 ft away and my plumber, instead of running a new vent pipe to the roof like he originally talked about, he connected the vent pipe back to the original vent pipe so now I have a 12 ft long horizontal pipe in the attic which looks weird? My concern is whether that is adequate venting, or is it too far away? I told him to redo and he was none to pleased and cited UPC code says it's okay. Can someone confirm this is true? Right now the argument is if I can find somewhere in code that says it's against code he will redo. I should point out I have tiled roof so not sure if he didn't do it due to laziness/taking shortcuts, or concerns about damaging the roof material or a mix of both.

 

[Terry]

I personally think it's okay.
UPC code says that the horizontal can be 1/3 third of the vertical and if more it gets bumped up a size.
A 2" vent will work for three full bathrooms though. It's already more venting than you will ever need, and if it's my home and I have a tile roof, I would install it just like your plumber did.

 

[Sponsor]

 

[3h4life]

Thank you Terry! You're expert opinion gives me relief!

 

[Jadnashua]

The horizontal section does need slope to it so it doesn't fill up with condensation or rain water...it needs 1/4" per foot slope down towards the relocated bathroom so it can drain. If it's running flat across the rafters, its not right.

 

[3h4life]

The horizontal section does need slope to it so it doesn't fill up with condensation or rain water...it needs 1/4" per foot slope down towards the relocated bathroom so it can drain. If it's running flat across the rafters, its not right.

I'll have to go up there and double check again, but I believe it's running flat across the rafters. Is leaving it flat a big concern, or likely not develop problems in the future? What is worst case scenario?

 

[Jadnashua]

Assuming it's an unheated attic, worst case, water pools, it freezes, and breaks. Not likely, but possible. Even the vent is considered part of the drainage system, and code calls for all pipes to have slope for proper drainage. Since the attic gets hot, in between the rafters, the lines could droop, too.

 

[Stuff]

What's up with the flex duct hanging free?

 

[Jeff H Young]

The vent is going to be fine. better than making another hole in roof. That vent can run flat if its 6 inches above the fixtures it serves which in the attic is a no brainer. I wouldnt worry about it drooping if supported every 3 foot or less