aligning tub drains in a slab foundation

[Chrisatunc]

I have a stall shower that's 36" wide and 36" deep. The actual base is only 36W * 32D and the drain opening is algined perfectly over the drain pipe coming out of the slab foundation.

I can only get a 32*32 or a 36*36 replacement base at my loca home improvement store. I want the 36*36 base, well, because it's bigger and it will fit in the space allotted. If I used the 32*32, the drain would align but i would have to 'build up' the side walls to elinimate the combined 4" void. Since the drain hole on the 36*36 is pre-drilled - and is 2" (on center) apart frmo the center of the drain pipe - how do you make the ends meet? Do you have to raise the stall to leave room for a diagonal pipe or something?

[isaacvs]

You could do that, or you could bust up some of the slab to get to the pipe underneath. It's hard work, but the advantage is that once you've uncovered the pipe, you can reroute it anywhere you want to go, and your finished product will look the way you originally wanted it to. If you raise the stall, make sure you're willing to live with it. Busting the slab will take less than a day. A shower stall that sits too high off the floor could bug you for the rest of the time you live in the house. If it were me, I'd bust the floor up.

[Chrisatunc]

So I bust up the slab...hopefully I'd find a PVC pipe that I would have to cut, then re-attach the 90degree elbow and the little amount of vertical pipe to bring it to drain level. Am I too ambitious to undertake this as I'm not an experienced plumber? I know that's a loaded question but the opinions I've received on this board are usually accurate.

Ironically I had a plumber at my house this morning to evaluate whether or not I needed a backflow valve (and I do, to the tune of $1400 b/c they want a manhole cover installed to access it). I asked the plumber this same question about the shower and he gave the same 'bust the slab' answer.

However - he also mentioned that there's a re-coating service that would put a new coating on my existing base and make it look spiffy for not a ton of money. The appearance is all I was going for in replacing the base; the walls will definitely be replaced (leaking tile; I'm going to put up acrylic walls) but the base just look ugly. He pointed out that there are re-surfacing companies (that put a new sheet of material on something) and there are re-coating companies (that apply a chemical coating to the existing surface). Any opinions on these services?

[isaacvs]

I haven't had any experience with those services, so I can't say one way or the other.

As for busting the slab, it's not too difficult. The trick is to make sure you bust the hole big enough to work in. If the slab is tight to the pipe, you may want to borrow or rent a rotary hammer drill - it will make life a whole lot easier. Once you're through, you should find pretty much what you described, except that there should be a 2" PVC trap, not just a 90 degree elbow. Cut that out with a hacksaw or a reciprocating saw, or if you're in close quarters, they make a cable saw for a few bucks that is indispensable in situations like that. Once you've got a clean end on the pipe, you can install a new trap and point it anyplace you like. It is necessary to have a trap, though. If you just use a 90, you're going to get a sewer gas smell in your shower. A small can of PVC glue, a small can of PVC primer, a few fittings, a little bit of pipe, maybe a cable saw, and a bag of concrete mix to patch the floor - the whole material list should be pretty cheap. And the busting of the floor is the only time consuming and physically demanding part. Once you're ready to cut the pipe, it should take no time and effort at all. If you're nervous about doing it, dry fit everything first to make sure you've got the correct angle on the trap.

If the old drain is only about 2" away from where you want to be, you probably won't even need any elbows. Just a coupling and a trap.

[Chrisatunc]

Cool. Thanks for the details. I forgot all about the traps.

Since this is the 2nd bathroom I will not have a deadline or loss-of-use hanging over my head. Maybe it's worth tryingif only to figure out whether or not I ever want to tackle my own plumbing stuff again.

-Chris