Drain line options?

[jp_fizzer]

Hello, I am replacing an old built in vanity with a new one and am trying to figure out what to do with the supply and drain lines. I have attached pictures of the existing configuration and the new vanity that will be going in. Before installing the new vanity I will be tiling the floor and walls. Originally I thought I had this all figured out because there is about 3" under the vanity and on the left and right sides but only about 1.25" behind the vanity available. I was going to cut off the supply lines near the floor, put 90's on back to the wall and then 90 back up the wall. Then install new valves and cut some small holes in the vanity to give access to the valves and use stainless braided lines to the faucet. For the drain I was going to bring it down the side of the wall, go under the vanity to the back where the slot is then come up and into a p-trap. However, I realized last night that this would create an s-trap which I understand is a no-no. So... any suggestions on how to install this without having to hack into my vanity? I do have room to go between the side of the vanity and the wall to get to the back wall but then there is not enough room for the drain line to run behind (unless I were to cut away the drywall and notch a bit of the 2x4's to create a groove for the drain line.

Thanks,
-jeff

 

[Jadnashua]

I think I'd get out the holesaw. You can make the hole smaller if you cut off the pipe at the connection but you have to measure very accurately, and if it is too tight, it might squeak as it expands and contracts when you dump hot water down the drain. Then install a new one after it's through the side of the cabinet. Assuming it is vented (and I can't tell from the picture), running it around through the wall without also changing the vent looks like it would make the vent connection too far from the trap. You need 1/4" per foot drop and snaking it through that corner would be a major pain, too.

You going to be tearing up th efloor? You might find it running under the floor, and relocating it could be easier (except maybe the vent). What's underneath - living space or basement?

 

[Sponsor]

 

[Terry]

Normally you would cut the cabinet for the drain.
If you lower the trap arm, you would need to lower the santee.

Just leave it where it is, you can cut the arm, slide the cabinet in, and then reglue the arm with a coupling.

Moving the water, you could run them through the bottom, or you could put them in the wall first.

I don't really like cabinets with legs, or with tops that hang over the sides. There is no easy way to deal with the small dust catching and thing catching cracks and crevices.
They look nice in a store, but there is also a reason that contractors started building in cabinets years ago.
Now a new generation is finding out the hard way why cabinets should be "built-ins".

 

[jp_fizzer]

Yeah, where it comes out of the wall is actually a santee that serves as the vent so I am kind of stuck with the trap arm at its current elevation. If I drop down out of the santee then I create an s-trap. The real problem with the way it runs now is that it cuts right through the middle of the vanity which limits the amount of things that can but put in it. I can probably re-work it so that it comes through the vanity but stays more near the back giving more usable space.

Terry, I totally agree with you. I tried to convince my wife that I would just re-finish the old built-in but she has a "vision" with 3"x6" bevelled subway tiles on the wall and 1"x2" subway tiles on the floor. When I try to explain the logical approach I just get "the look". This is actually the reason I was hoping to run the plumbing on the ouside of the vanity. That way when something invariable falls back behind or whatever it is just a matter of undoing two faucet risers and a p-trap and that whole vanity would slide out. Once I start putting plumbing through it I will never move it. On the plus side, if that is the case then there is no point in me tiling behind it

 

[hj]

vanity

IF you have any reason to assume you will have to move the cabinet once it is installed, you might as well put it on wheels and use rubber hoses for the connections. Personally, I have never known any reason to move/remove a cabinet, unless it was being replaced.

 

[jp_fizzer]

Interesting development. I was just opening up the wall to consecutive studs to make it easier to put up a drywall patch when I happened to notice there was already a hole drilled in the far stud. I decided to open up the adjacent wall and sure enough there is already a hole in that stud as well. I am wondering why a previous owner would have changed the drain so as not to use those holes?

If I were to cut the pipe on the top and bottom of the santee I could rotate the santee so that drain ran inside the wall through the hole in the stud, make a 90, run along the inside of the back wall and then come out directly behind the sink. Does this make sense? Is there a problem with this like the distance is too far from the trap to the santee?

thanks,
-jeff