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osmotik 03-26-2011 10:12 PM

removing iron drain from foundation
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I'm in process remodeling the bathroom in a guest cottage. As part of the remodel, I'm moving the toilet, sink and shower. based on the way that the current drains are set up (not in the right spots), I think that the best thing to do is to cut the drain at the entry to the building, and rebuild the drain system new (using plastic) and hook the new to the old with one of the rubber sleeve adapters. I have two options where to do this.

1. cut the drain just on the inside of the foundation. there is very little working space there (see the photos) because the first joint (a Y going to the main stack and toilet) is tight almost up against the foundation. I think that I should be able to make the cut, but I'm concerned about being able to see well enough and work well enough to get the transition done well (never done one before)

2. cut the drain outside the foundation. this should offer plenty of working space, and I already dug the hole, but I'm a little nervous about getting the old pipe out of the foundation. I was able to clear holes on the two sides of the drain, but there appears to be concrete both on top of and below the drain. without cutting it, I don't really have a way to tell how rigidly attached to the foundation it is.

based on all this, I've got a couple of questions:

- where should I cut the drain?
- what's the preferred cutting method (I've heard sawzall and special pipe cracking tools can work)
- any other tips?

thanks in advance

oh'mike 03-27-2011 06:43 AM

I think I'd cut it out side----Actually make two cuts---

Rent a chain breaker (sometimes called a cracker or popper)

Break it about 12" from the foundation---an again about 3 or 4 feet from the foundation.

Remove the section----now you have room to swing a sledge hammer--tap the pipe into the crawl enough to get your breaker onto the inside pipe---

Break off the fittings inside--wiggle the pipe out of the foundation.----Mike---(good pictures!)

plumber666 03-27-2011 07:46 AM

Chain cutters outside the building or a grinder with a zip cut wheel, or a big gas cut off saw. Take a sledgehammer to the rest of it.

osmotik 03-27-2011 10:35 AM

thanks, i was thinking outside would be easier too. the second cut makes a lot of sense to get some swing room for a sledge. Are the transition fittings rated for direct burial, or do I need to install a box around it?

the_man 03-27-2011 10:38 AM

one thing to add... you'll probably need a rotohammer to enlarge the hole thru the foundation for ABS/PVC pipe, the outside diameter on plastic pipe is larger than the cast iron. seal the hole thru the foundation with mortar when you're done, and maybe think about an outside cleanout for the sewer while you're at it

osmotik 03-27-2011 11:57 AM

With regards to the pipe size, it's currently 4" for the buried section and continues to 4" inside the building for the main stack. The drain serves a toilet, sink and shower, which I believe only requires 3". Would it be appropriate to transition to 3" outside the building? The would make it easier to thread through the foundation, and also would give me a little more space to run the necessary fittings once I am inside the building.

oh'mike 03-27-2011 12:31 PM

You will be fine with 3"---Make the transition outside---Mike---

the_man 03-27-2011 01:00 PM

3" is adequate for the size of the drain, however some municipalities require a 4" building drain before the pipe exits the foundation. shouldn't matter for functionality, but if a permit is pulled or inspection done after the fact it could be an issue

osmotik 03-27-2011 01:34 PM

Just want to re-post one question that got buried by the other posts. Are the transitions from cast iron to PVC rated for direct burial, or should I install a box?

the_man 03-27-2011 01:51 PM

ferncos and stainless steel nohubs are rated for direct burial. if you use a nohub coupling, make sure it's sized for CIxPlastic

osmotik 03-27-2011 02:05 PM

Thanks for all the help. I will check on the local code requirements, but will aim to transition from the 4" iron to 3" PVC outside the building, then will have a clean 3" PVC to work with once I'm inside.

plumber666 03-28-2011 07:28 AM

If you ever plan on adding any plumbing to the house in the future, I'd leave it 4". The code I work with only allows one toilet on a 3" line, and any building drain must be 4" or larger. The diameter difference between PVC/ABS and cast iron is minor. Like a 1/8" or less. Always better to oversize than undersize.

osmotik 03-28-2011 12:30 PM

interesting point. in this case, the building is a garage/in-law suite, so unlikely that I would add another toilet. but I guess if 4" is doable, no reason not to have it.

osmotik 04-04-2011 12:05 AM

I rented a snap cutter today and was able to remove all the DWV pipes both inside the bathroom and the one pictured. Thanks for the good ideas. The snap cutter worked great, but man was the 4" vent stack heavy! The only advice I'd give anyone setting off on the same task is to think ahead about the order you make your cuts, the snap cutter puts a lot of torque on the pipe, so I think it's best to start cutting at the vents out the roof or the fixtures so that things aren't twisting around on you a lot (I did the opposite leaving a 8ft straight section of vent till the end which I couldn't keep from spinning, so had to pull it out of the roof in one piece,)

plumber666 04-04-2011 07:24 AM

Good on ya for going for it!

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