I just purchased a slab foundation home with a shower-only stall in the master bath. I want to replace the shower with a garden tub without jackhammering up the slab.

The layout is such I cannot expand to the sides to allow the tub to be placed in the current location of the shower. (Side wall backs up to the washer/dryer plumbing.) I CAN expand back, making the bathroom deeper. My idea is to put the garden tub farther back and put it up on a platform, starting the platform where the current shower drain is. How far away can I realistically have the tub drain from the current drain, and how raised will the tub/platform need to be?

Jj

This is not to scale at all, but generally here's a drawing of what I have and what I would like to do... see attachment

Hi JJ,

"How far away can I realistically have the tub drain from the current drain, and how raised will the tub/platform need to be?"

Since you have furnished no measurements and I have no idea how far the old tub trap is away from any vent I can't answer that question. The platform will have to be raised to accommodate a "P" trap assembly and allow for slope back to the tub drain. Since you can not double trap a fixture you will have to remove the old tub trap and slope the drain line 1/4" to the foot back to a 45 and jump to another 45 under the slab to connect the new drainage to the old existing drain line. If this job will have a permit pulled and will be inspected you may have to run another vent for the garden tub.

Hi JJ,

"How far away can I realistically have the tub drain from the current drain, and how raised will the tub/platform need to be?"

Since you have furnished no measurements and I have no idea how far the old tub trap is away from any vent I can't answer that question. The platform will have to be raised to accommodate a "P" trap assembly and allow for slope back to the tub drain. Since you can not double trap a fixture you will have to remove the old tub trap and slope the drain line 1/4" to the foot back to a 45 and jump to another 45 under the slab to connect the new drainage to the old existing drain line. If this job will have a permit pulled and will be inspected you may have to run another vent for the garden tub.
Good luck, Tom

Okay... measurements. The back end of the bathroom (past the area where the washer/dryer hookups are) is wide open, so there's room to expand back and to both sides past that point.

If the job won't be inspected you can come off the tub drain with a DWV elbo and arm over to the shower stub up and connect with another elbo.
That way you'll be trapped and vented. The only other way would be to take up the floor and remove the shower trap. You may then connect to the drain pipe and run to the garden tubs trap where the tub ties in. You may not double trap a fixture so these are about your only choices. Regards, Tom