Bathtub drain offset

[Dave&Carley]

Hi everyone,

My wife and I are renovating the master bath. The old tub had a back-center drain (which is next to impossible to find in the size we need for under $1500) SO we decided to get a right-hand drain tub and relocate the drain. It's in a slab but we're not above breaking the concrete and digging down in the dirt, so that's what we start doing. Unfortunately, the main sewer line is directly under where the new drain needs to go, meaning it's in the way of where the p-trap would go.

My question is, for a tub only (no shower) can I cut the tail piece under the slab level, put a 90 on it and run a horizontal piece of pipe over (making sure to put a grade on it for proper drainage) and 90 into the drain? The run is 29" from center of the current tail piece to center of new drain.

If not, what's my best course of action?


Photos for reference:

 

[PlumbNuts]

My question is, for a tub only (no shower) can I cut the tail piece under the slab level, put a 90 on it and run a horizontal piece of pipe over (making sure to put a grade on it for proper drainage) and 90 into the drain? The run is 29" from center of the current tail piece to center of new drain.

Yes, you can do that. I would cut and turn as low as possible and use long sweep 90's if you have room. That will make future drain cleaning easier with all of the turns in it.
Side note: it does not appear that you have cut your concrete far enough to allow for the waste and overflow connection. A tub does not connect directly under the drain. Look at your existing drain connection to see an illustration. You may have already known this, just making sure it wasn't overlooked.

 

[Sponsor]

 

[Dave&Carley]

Yes, you can do that. I would cut and turn as low as possible and use long sweep 90's if you have room. That will make future drain cleaning easier with all of the turns in it.
Side note: it does not appear that you have cut your concrete far enough to allow for the waste and overflow connection. A tub does not connect directly under the drain. Look at your existing drain connection to see an illustration. You may have already known this, just making sure it wasn't overlooked.

Will the sweep 90's help avoid water or other things from getting stuck and causing odors? That's been the biggest concern I've read on other threads doing similar things is that you can get odors from water, soap, etc not fully draining.

As for the concrete, I know It's not back enough yet. We just did a rough opening so I could dig more out and see what I was dealing with underneath. But thanks for the heads up regardless.

 

[wwhitney]

Tub and waste overflows come in various confirmation: e.g. drain outlet vertical under the overflow, vertical under the drain, and horizontal left or right under the overflow.

So I'm wondering if there's a waste and overflow available that would give you a drain outlet horizontal under the drain, back away from the overflow.

Interestingly enough, GA amended the IPC to remove the language in 1002.1 stating that from the fixture outlet to the trap, "the horizontal distance shall not exceed 30 inches". So apparently in GA you could run your tub waste farther before hitting the trap, although that may not make it a good idea.

https://up.codes/viewer/georgia/ipc-2018/chapter/10/traps-interceptors-and-separators#1002.1

Cheers, Wayne

P.S. How deep is the building drain, is there really not enough vertical height for a trap between the drain outlet and top of the building drain?

P.P.S. What about putting the trap on the right, running the vent up into the wall, and bringing it back around to connect up with the existing vent?