Hello, My husband and I are doing a bathroom remodel and are trying to save money by doing some work ourselves. We are trying to move the vanity sink drain about 6 inches to the left. My only real concern is if the sink is going to drain properly once we hook it up. Here's some background info. We have a single story house with two full baths that share a wall and share plumbing. We had galvanized pipes that have all been replaced in various stages (attic lines first, then sewer line re-route to move everything out from under the house when we had foundation work done, and 75% of the vertical pipes done) All that is left are these bathrooms and the kitchen lines. So we gutted the bathroom down to the studs, cut out the galvanized pipes and replaced everything with cPVC. Our old vanity was a single right sided sink on a 60in top. We purchased a new vanity with the sink now sitting center. We were able to move the hot and cold lines over to the left to clear the new drawers. Now we have the drain to contend with. I have done some research on google and I believe that we have a soil vent that comes straight down from the roof and through the foundation. There is a second line that comes down from the attic that drains the AC unit and it connects to the vent pipe about a third of the way down from the ceiling. If you follow the vent pipe down there are two connections coming out of the vent pipe for both the master sink and the hall sink. My husband cut the drain on our side, added an elbow and some cPVC to direct it to the left. I'm not sure what his plan is from that point. Adding another piece that he can connect the p trap to that we can connect the drain to... I will add photos that will make things clearer. Right now the drain pipe just ends at the cold water valve. We plan on figuring the rest out tomorrow when he gets off shift (Fire Fighter) The Vent pipe is 1.5 inches in diameter and the drain will have moved approximately 6 to 8 inches horizontally to the left. Do we need to slope this pipe? or is it close enough? Also the toilet has it's own larger diameter waste vent pipe that is about 3 feet to the right of this. Also any suggestions for how to finish this drain? What type of connection would be easiest to turn it to attach the p trap? Thanks!

 

Welcome to the forums!

All drain pipes need to be sloped. On a short run like that it doesn't need to be much, but 1/8" slope per foot of run is about the minimum you want, more if possible.

A close up picture of just the new drain work would be helpful. I see a couple of issues:

1. Many plumbing codes say you can't glue PVC to ABS; you have to use a shielded rubber connector. For the short piece you need, I'd just go with ABS.

2. Having that short elbow to turn the pipe to the left has two problems. It's going to be a clog magnet because of the double turn so close, and it makes the PVC stick out beyond the surface of the wall. Better to plug that fitting and cut in a new sanitary Tee above or below the Wye that's in there. The leg of the Tee will face to the left allowing a straight shot in with the short piece of pipe. Then you put a long sweep elbow on the other end with a trap adaptor to connect to your trap.

Good luck!

 

First some terminology. CPVC (chlorinated polyvinyl chloride) piping is not used for drainage. CPVC piping is a yellowish beige color. Regular PVC piping IS used for drainage and is white in color. Black drainage piping is ABS (Acrylonitrile butadiene styrene) and is often used instead of PVC, often a regional distinction. PVC and ABS are generally NOT used together as they have different requirements when solvent welding.

A "soil stack" is a vertical pipe that carries toilet wastes. A "vent stack" carries only air and a "drain (or waste) stack" carries non-toilet wastes. A "trap" is a specific design of piping bend that will trap a specific amount of water to prevent noxious gases from traveling through the open drain. ALL traps need to be properly vented.

Your second picture shows some strange construction with that trap "buried" within the wall and a long "riser to the inlet of the trap. This is rarely allowable as it can lead to the trap "siphoning" and loss of the water seal. What does this trap serve, a floor drain, bathtub or perhaps a washing machine? Also, the stack above this trap's "sanitary tee" is a vent and therefore the "trap arm" from the vanity sink MUST have a "revent" connecting from the trap outlet to a point above the upper trap connection to the drain.

And why the smaller fittings on the vanity trap arm?

 

Furd,

OP said the line to the buried trap is an A/C condensate drain. That makes that section of vent a wet vent, but given it's just for the A/C I wouldn't think it's a problem that requires re-venting...but I'm not sure.

Those aren't smaller fittings on the lav drain...the pipe just dies right before the cold water supply line as it isn't finished yet with an ell and trap adaptor.

 

Thank you for all the advice! We have decided to go ahead and start over. We are going to cut that section out and create two separate drains.using the correct pipes. We also didn't even think about the sheetrock issue so this will fix that as well! I'm headed to Lowes so hopefully they can help me out!