Moving a shower drain


  #1  
Old 02-18-03, 02:58 PM
Jonas Calhoun
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Moving a shower drain

Hello all!

I'm finally getting around to installing my basement bathroom. The previous owner of the house roughed it in, putting in the drains for the shower and the toilet. However, it appears I am going to have to move the drain for the shower (at least, I haven't measured for the toilet yet). He didn't take into account the drywall being in place. Anyway, there was a similar post on these forums here: http://forum.doityourself.com/showth...ment+and+drain
I have a slightly different question though, I have decided to cut the concrete to move the drain (I have an air hammer, so it shouldn't be too bad, right?). To install the 2 right angle pipes and enough of a stub that the shower drain can attach to it will require about 6 inches of room, right? How thick is a concrete slab in a typical basemet? Will I go through into dirt? What if water starts coming up through the hole?

Or, instead of putting in all that pipe and fittings, can I cut a trench in the concrete, put some sort of water barrier on it, and then have that trench empty into the pipe?

If I need to describe more, please let me know. I can attach pictures of what I am talking about too.

Thanks for all the information! I've now got another site to dig through!
 
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Old 02-18-03, 06:36 PM
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You will have to forget your plans of a trench. Your concrete floor is probably 6" deep. You will have to cut down to your existing drain. Hook into it, and re-concrete. This is not a very good type of job. Especially if your only moving it an inch or so. I think I would maybe think along the lines moving your wall or something easier. Good Luck
 
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Old 02-18-03, 08:57 PM
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Of course, you can always do a tile shower, in which case the drain doesn't have to be on center... Then you can leave it and not dig it up... If you have to move it, definitely just break up the concrete, dig down to the pipe... you should just break through to dirt after about 6" of concrete and reinforcing wire... carefully uncover the existing pipe and then move it by adding to it or cutting it off shorter...
 
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Old 02-20-03, 10:20 AM
Jonas Calhoun
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Thanks for the replys guys. One piece of info I forgot is my main stack is about 2 feet from where the pipe is now, so I'm not too worried about cutting concrete all the way to the stack if needed, and then run all new pipe.

One more question, though: What would be better, using my (already owned) air hammer, or would I be better off renting a concrete saw? Also, how would I go about scoring the line that I will be cutting? Use a cold chisel?

Tiling isn't really an option, the wife already picked out the shower she wanted ("Well, if you have to cut the concrete anyway, ....").
 
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Old 02-22-03, 09:49 PM
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I personally prefer just using the hammer with no concrete saw... The job will be dusty to begin with but if you use the saw the dust is multiplied tenfold... Also the concrete patch will be better if you are filling a hole with rough edges instead of smoothly cut edges...
 
  #6  
Old 02-24-03, 12:35 PM
Jonas Calhoun
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Well, I started in on it this weekend. That air hammer made the job much easier. I didn't get very far (got caught up in doing some other stuff), but now I know a little more of what I am in for. In about an hour, I had a hole around the pipe about 4 inches deep, and about 1.5" around it.

At least there is a P-trap already in the drain, from the level of the water, it appears to be under my slab. It turns out I have to move the drain about 6", so I should have enough room for a couple of elbows and a short piece of pipe.

New questions, though: How much of a stub do I need to leave on the pipe that the drain connects to? The drain I picked up at the local big box fits over (!) the pipe, and supposedly fits flush with the concrete.

Also, I'm guessing I need to put in some sort of slope to the pipe, how would I go about doing that and still keep the stub vertical? (Is it 1/4" per lineal foot on the slope? Will more/less hurt?).

Oh, and as far as dust, I've got a good mask I use for painting, and have a friend with the shop vac try and keep up with the aggregate coming out of the hole--seemed to work pretty well (hey--that dust isn't explosive, is it?)

Thanks again!
 
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Old 02-24-03, 06:32 PM
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Well, if you are turning above the trap, which is what you need to do, then don't worry about the slope... The piece of pipe between the two elbows is going to be so short, you won't be able to get an accurate reading on a level anyway... You can assume that the original plumber put the trap and branch drain in correctly with the appropriate grade... The little bit above the trap is meaningless (of course, you don't want it grading backwards to an extreme but it will still work)... As to the drain height, regardless of anything you read on the shower or the drain assembly, the most effective way to get the height of the stub out correct is to mount the drain on the shower and then level the shower out in the middle of the floor with a block or two sitting under the back of it... Now measure from the floor up to the hub top so you can get an accurate measurement of how high the pipe needs to stick up above the floor... The air hammer is the right way to break it up by the way, but of course, you want to be careful not to break the existing pipe... Also, once you get a small hole started all the way through to the dirt, the rest of the concrete will break much easier, so go ahead and break out plenty to leave yourself enough room to work... No need to skimp here, and you can always repour the excess opening when you are done...
 
 

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