Bathtub install help

[Shark77]

I am tackling my first bathroom remodel and am a little stuck with the bathtub install. I am installing a Kohler archer 60"x30"x19" tub onto a post tension slab. The plumbing throughout the house is ABS and the Kohler drain is PVC. I cut out the previous tub's drain, then fit the Kohler parts onto the ABS using green ABS-PVC transition glue at the ABS coming out of the slab, and regular PVC primer and glue on the rest.

Although I dry fit the tub 3-4 times to get the fit just right, when I glued the drain, it ended up slightly higher than planned, and now I am having trouble getting the tub level because the drain is pushing up on the tub. I even layed down a mortar bed, but pulled it out because I knew the drain was blocking me from achieving level. Once I pulled the tub back out, I noticed the bathtub drain was pitched the wrong direction causing the water to drain slightly uphill-I know this is bad and will cause drainage issues down the road.

So I know I have to redo the plumbing. I think if I go a half inch lower everything will work out. I think the key is having about an 1/8th inch gap between the top of the tub drain rubber gasket and the bottom of the tub to force the proper 1/4" per foot slope. Am I missing something? I still have about 2" of ABS sticking out of the slab that I can attach a new sanitary tee to. If I chip out the concrete around the ABS I think I will get to the p trap, but don't think I need to go that far. Am I good using the ABS-PVC transition glue at the sanitary tee, or should I go with an ABS tee and pipes, then use proflex couplings to attach the tub drain and overflow PVC pieces to the ABS?

Also, when I pulled out the tub, I noticed the supports along the bottom were slightly cracked-should I return the tub to Lowes for a new one? The inside of the tub looks great-no cracking at all.

 

[Terry]

I normally use a coupling like a Proflex, Mission or Fernco. Metal wrapped of course, to transistion between ABS and PVC.

For the waste and overflow, I install on the tub first, glue it up, and then remove.
This makes sure that it fits the tub, with all the right angles.

The next step is to install and drop the tub over it.

I think you need to dig a bit deeper on that.

I can tell if the bottom is a problem from the pictures.

 

[Sponsor]

 

[Dj2]

Like Terry mentioned, you must install the drain on the tub first. Now you may ask: so how to connect the drain to the vertical waste line? A. use the little opening in the wall to reach it.

You can use an ABS waste set, which will glue to the existing line in the concrete with ABS cement. It looks like you may have to expose more of it to get a good connection.

 

[Dj2]

Almost forgot: did you buy a new tub in its original box?

 

[Shark77]

Thanks for advice guys-I really appreciate it.

Terry, I originally fit the drain like you said but when the overflow was too high upon the initial dry fitting, I trimmed the overflow drain length instead of trimming the ABS coming out of the ground-rookie mistake. And just to confirm, you are saying I should fit the drain on the tub, then take everything off to glue it together, then glue the entire l-shaped drain piece to the ABS coming out of the ground, then install the tub on top of the drain?

So now that I am going to cut out the drain I just installed so that I can reinstall it with the correct angles, I'm worried the drain will sit too low. Any tips to get that height correct if I am sitting too low?

Also, regarding the couplings, I've got 1.5" ABS coming out of the ground and connecting to a PVC sanitary tee, and everything else PVC after that. To my knowledge there is no coupling that will join those two pieces. I live in AZ and am pretty sure green ABS-PVC transition glue is allowed by code since 2012-is that the way to go? Or should I buy an ABS sanitary tee, and some 1.5" ABS pipe, and join that to the PVC main and overflow drains with couplings?

dj2, the tub is new in the box. I talked to the store where I bought it today and they are going to replace it free of charge.