New tub to old drain

Hi folks, long time lurker, first time poster.

I am doing a renovation in a basement bathroom in a house built in 1967. I am replacing a fiberglass shower stall with a tub. The drain pipe for the shower is 1 1/2" steel. It was set into the shower drain with lead, it has no threads and sticks up about 3/4" above the concrete floor.

I'm using a tub designed for concrete floors that has a raised bottom to let the tub shoe fit above the floor. It wants the top of the trap adapter to be level with the floor or below. So I need to shorten that drain pipe. I've read enough to know that there are two proper ways of doing this. One would be to cut the pipe below floor level, put a banded coupling on it and a PVC trap adapter. The other would be to excavate down to the trap and remove the pipe from it and replace it with a piece of PVC. If it's threaded use a threaded PVC adapter, otherwise use a donut.

My question: are those my only two options? Neither one is very appealing. To use a banded coupling I'm going to have to go down probably 6", with a hole big enough to cut the pipe 5" below the surface and get a wrench on the coupling, which sounds like a lot of concrete to come out. If I remove the pipe I probably have to go even deeper, and run the risk of breaking the trap.

One thought I have is that the tee for the tub shoe fits nicely into a 1 1/2" banded coupling. Would it be a bad idea just to attach the tee directly to the pipe with a banded coupling? I would still have the tubing going into the 1 1/2" pipe which would prevent obstruction.

Second thought is that the tee has threading on the bottom on the outside. Is there some sort of fitting that the tee is meant to attach too? Is that another option?

Another thought to cut the pipe off flush with the floor, thread it and put a brass trap adapter on.

Do any of these ideas make sense? Or am I just psyching myself out and should get busy breaking concrete.

I appreciate any insights.

Thanks.

The first thing that comes to mind is, "what kind of tub are you using that has its drain in the same location that a shower stall would have had it?" The tee's thread is for a slip nut to be used in addition to threading the tailpiece into the tee. You would NEVER, or at least not easily, thread that pipe in the floor. The "banded" coupling is NOT designed to go over the threads on the tee and will NOT seal on them.

Thanks HJ.

hj said:

The first thing that comes to mind is, "what kind of tub are you using that has its drain in the same location that a shower stall would have had it?"

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The old shower was a free-standing fiberglass enclosure. The old bath was really rough, with no walls and a concrete floor in an unfinished part of the basement. Since I have to add walls anyway I can put them where I need them. My plan is to fit the tub and then build three walls around it.

hj said:

The tee's thread is for a slip nut to be used in addition to threading the tailpiece into the tee.

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Like a belt and suspenders?

hj said:

You would NEVER, or at least not easily, thread that pipe in the floor.

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OK, rule that out.

hj said:

The "banded" coupling is NOT designed to go over the threads on the tee and will NOT seal on them.

Click to expand...

OK, so it sounds like I'm busting the concrete.

Any tips on cutting the pipe evenly 5-6" below floor level?

I can also get a flexible (not banded) coupling that connects 1.5" tube to 1.5" pipe. If I used that I would only have to go a couple of inches down. If I bury that in concrete is it OK?

Thanks.

An update: I looked into the pipe with a light and found that the piece sticking up is only about 3" long, it goes into a threaded fitting. So I used a cold chisel to chip around the pipe down to the fitting. There wasn't enough of the pipe sticking out to get a good grip with a pipe wrench, so I cut the pipe lenghtwise with a reciprocating saw and it came right out. I think I'm on my way.