DWV assistance needed

HackingHowie · 06-28-2010, 11:22 PM

I'm building a camp up north and we've run out of money a long time ago, So I've gotta do a lot of work myself that I'd ordinarily farm out. The DWV is one of the projects I'd like to do myself. However I would like to do it right. This forum looks like a great place to find solutions and answers to some of the upcoming problems I'm sure to encounter. The Camp was really just put together fast without plans with not a lot of thought on interior layout so now things look a bit more complicated than maybe they could have been. It's a 1& 1/2 story gable structure on a full foundation. (So there's really three levels) A professional plumber roughed in the bathroom in the slab of the walk out basement So I'm off to a good start. I'd like to install a 1/2 bath and a slop sink on the top floor there will be no bathroom on the middle floor. There is a 4" PVC stub coming out of the slab and it's headed upstairs. Here's my first question. Can this stack be offset to get it near where I need it to be for the 1/2 bath and where I would like it be when it exits the roof?

**phishfood** · 06-29-2010, 02:17 AM

Is there a vent for the bathroom that is already roughed in? I would think that there would be, 4" is way overkill for venting a bathroom.

So, if your answer is yes, than the answer is yes, you may offset the 4".

Next question?

HackingHowie · 06-29-2010, 09:38 AM

Thanks Phishfood! The plumbing under the slab has a 2" stub headed up where there will be a lavatory will be and also a 2" pipe in another place headed up labeled "Vent" I have some photo's of this work before they covered it up so I could see what they did later if I had to know. In conversation it was brought to my attention that the 2" vent was to vent the fixtures at ground level and any bathroom stuff on another floor was to be vented to the main stack. I think I understand that but I'll ask some more about that later. My next question is about upper floor. I need to drain a lav in the 1/2 bath and also a slop sink in the adjacent room. My thoughts were to install a 4"x2" sani-tee in the stack to create an arm that will drain the lav and just put a 2" tee in that same arm to create an arm running perpindicular to the lav arm that will drain the slop sink. Is this actually putting two p-traps on one arm and is prohibited? Or should I install two different sani-tees in the main stack one for the lav and one for the slop sink?

**phishfood** · 06-30-2010, 01:42 AM

Under some codes, there are piping arrangements that will allow you to do something similar to what you describe with the lav and slop sink. But not knowing the codes in the area that you are building in, I would say play it safe and use 2 T's in the vertical stack.

HackingHowie · 06-30-2010, 10:00 AM

The build is in Central Maine. I'm pretty sure the code is based on the UPC. The offset in the main stack is due to the 12-12 pitch of the roof. Being it headed up out of the basement it can't just go through the roof where it ends up because it's not high enough to accommodate the fixtures I'd like to see on the top floor. (The Half bath and the sink). So when the stack gets to the roof line I'd like to install a 45 ell and run it parallel to the roof line for a distance before it turns 45 degrees again and exits the roof. Can I attach a fixture arm into the stack as it runs 45 degrees by installing a 4"x2" Wye in it instead of installing a sani-tee? The 2" part of the Wye would be horizontal in this configuration and looks like it would work for what I need to do. Just want to know if this could be an option.

**phishfood** · 07-01-2010, 02:01 AM

Yes, that should work just fine. In that application, the use of the wye will not break the hydraulic gradient between the trap and the 4" vent.