Basement Bathroom sink rough in, where to tie in the sink?

[Michael S]

Hi all,

Not new to reading the forum, but new to posting. We are finishing our basement, and are now onto the bathroom plumbing. The shower drain and toilet drain have been roughed in underneath our foundation, but the sink is not, leaving us to best decide where to tie the sink drain in. Below is the picture of the current layout. The lavoratory will be going against the same wall as the toilet.

My question then is where to tie in the sink? If I tie into the 4” pipe behind the shower, it will have to go below the clean out (not sure I can do that), but this may be the easiest way. Otherwise, I would have to tie in to the 2” pipe behind the shower wall (?shower vent) and travel over 8’ to get there, with one 90 degree turn.

Any thoughts or help would be greatly appreciated. Thanks!

 

[Geofd]

your only real option is to tie into your 4" and bring the vent back and tie in.....check your local code to see vent distances on 2" its 6 ' in mass...you could have cut a wye into the toilet line and brought that up in the wall stubbed out for your drain then tied back into your vent stack....I don't know how to show you by drawing on the computer..
im sure someone else can draw it out for you....

 

[frodo]

you are pretty much screwed, I looked at your pictures this is what i see\
the 4'' looks like a fitting is sticking above the concrete. SOOOO
your ONLY option with out busting the floor.
is to, remove th pipe from inside that fitting, you need a ''rambit'' tool, that drills the pipe out of a fitting. you can find one at a plumbing supply.
drill the pipe out. insert a 4x2 pvc BUSHING https://www.supplyhouse.com/Spears-437-420-4-x-2-PVC-Schedule-40-Spigot-x-Socket-Bushing
into the fitting. you are going to need to buy a
https://www.supplyhouse.com/Spears-P403-020-2-PVC-DWV-Sanitary-Street-Tee
insert that tee, into the bushing

why am i making you do this? you are bit in the arse by height the sink drain can not be any higher than 19'' center of drain to floor.

 

[Michael S]

Thank you both for you input!

Frodo, there is 12.5” clearance from the toilet to the back wall and it’s over 15” clearance OC to the side walls for the toilet, so I think I am ok there (the picture at the angle I took it to show pipes is a little deceiving, sorry about that).

Below is a closer image of the 4” piping. You are correct that there is a fitting coming out of the concrete into the 4” PVC. I am wondering if I can tie in at the 4 inch by cutting the pipe a bit above the fitting coming out of the concrete and inserting a ?sanitary tee there (4x4x2). If needed I may be able to remove the coupling and bushing above the 4” piping and extend it even further up (and replace it up higher) to give a bit more room for the tie in.

Thoughts? Thanks again!

 

[frodo]

maybe.
do your math,
you can not be higher than 19'' with the outlet to the sink, and you need 1/4'' per foot fall from the centr of sink to the 4'' drain
what is the distance? looks like around 5' so that is aprox 1.5'' fall
if you use a loop vent..