Basement Rough In Advice Needed

mikemille · 02-17-2007, 10:52 AM

I'm wanting to put a new bathroom in our basement with a tub, toilet, and sink. There's a picture attached of the rough-in put in when the house was built. I'm trying to figure out what pipe will go to what fixture and how it will all be vented. As a test, I popped off the caps and poured water into each pipe. The smaller pipe on the left side of the photo has a trap in it (water was visible in it). The other two on the right drained (no water visible). I'm assuming the pipe on the left side is for the tub, and the larger pipe in the middle is the toilet. But I'm not sure about the smaller pipe on the right. Can I drain the sink into that pipe???

Questions:
1) Is the small pipe on the right the vent for both the shower and toilet?
2) Can I drain the sink waste into that pipe on the right???

The other picture is a pipe going to the second floor. Someone wrote "vent" on the joist. I'm assuming I hook on to this guy and run it over to the rough-ins to provide venting.

Currently, I'm planing on droping down vents to that pipe on the right and another vent down to the new sink. The sink's waste would be hooked to that pipe on the right.

Please let me know what you think, and what configuration I need.
If that pipe on the right is a vent and I ran the sink drain to it, does that make it a "wet vent" for the tub/toilet?

Other Questions:
3) Should I drop down a vent pipe for the tub pipe on the left?
4) If I use the pipe on the right for the sink drain, is it then considered a "wet vent" for the toilet/tub, and is that ok?

Thanks!

Ron The Plumber · 02-17-2007, 07:57 PM

I have a hard time determining what is going on in the pictures, you might be better off calling in a plumber locally and getiing a better understanding on what you have there.

Codes do very from place to place, and my code may not be what you use there.

mikemille · 02-18-2007, 09:26 AM

Thanks for the advice. I may very well hire a plumber to do the job, or at least get one to verify my plan on what I want to do. I was hoping you could help me speculate what's going on under that concrete.

I'm going to attach a drawing I threw together of what I'm planning on doing. The gray lines represent the pipes in my first posted photo. The red represents what I know is under the concrete (the only thing I know is there's a P-trap under the pipe on the left). The green lines represent the pipes I would try to run based on what I know so far.

I live in the midwest (Missouri)...I'm not sure what codes apply here.

It's my understanding the builder put in a full bath rough-in. If so, then what do you think is under that concrete???

Thanks.

Ron The Plumber · 02-18-2007, 09:36 AM

Tieing the sink into the vent of the toilet will make it a wet vent, allowed by code here if the vent is 2" and the proper fitting were used under the concrete, so not knowing what is under the concrete, I can't say you can do that.

Where is the vent for the tub, here each fixture must have it's own vent, again your code maybe different.

mikemille · 02-18-2007, 10:52 AM

I'm guessing that pipe on the right will serve as the vent for both the toilet and tub. I need to find out if a "wet vent" is ok for my situation. I wonder if anyone out there knows the code for this. I'm assuming the builder put in the rough-in correctly for the area.

While googling, I found a post with a person asking questions about a similar rough-in layout. The following response seems to apply to my situation:

Quote:

The pipe for the basin should have been located to come up through a future wall plate. This pipe would extend all the way through the wall to be connected to another vent pipe somewhere in the ceiling because it probably vents the future toilet connection as well. A horizontal pipe ties into this pipe about a foot off the floor with a sanitary "Y" fitting and spans the distance from where it comes through the floor to your basin drain location. If this span exceeds 5 feet you will require a vent loop to run past the basin, up through the wall and back to tie into the first vent pipe. The pipe for the toilet should be 12" (to center of pipe) from any future finished wall.

When you install the sink the trap will allow you to redirect the waste water towards the drain pipe so you don't have to be exact where you bring the pipe out through the wall. Always maintain 1/4" on 12" slope for your horizontal drains. I would avoid any flexible waste pipes unless they have a smooth bore inside.

I took some measurements and the pipe for the toilet is 12" from where the back wall of the new bathroom would be framed out. The pipe on the right would come up through the new back wall bottom plate. My span to the sink would not span 5 feet, so I guess I don't require a vent loop.

The post seems to imply a "wet vent" may be ok for the toilet.

As far as the vent for the tub, I've seen pictures in my plumbing book where the tub and toilet share the same vent. But I haven't seen any pictures in the book showing the tub and the toilet sharing a wet vent. I can't find any pictures anywhere of my situation/solution.

mikemille · 02-18-2007, 10:55 AM

fyi...I ran downstairs and measured pipe diameters:

tub pipe on the left, ~ 2 1/4 diameter - so I guess it's a 2" pipe
toilet pipe in the middle, ~ 4 1/2 diameter - 4" pipe
pipe on the right, ~ 2 1/4 diameter - 2" pipe