I need to replace a leaking toilet, but the distance from the drain to the wall is about 10.75". The selection of toilets that I'm finding in the 10" rough-in range is pretty pathetic and overpriced, especially water-conserving ones.

Ideally I'd like to relocate the drain 2" so I have a standard 12" rough-in. The problem is that my house is on a 4" slab-on-grade (with just bare dirt right under it), and the plumbing--all original cast iron-- is thoroughly entombed in the concrete. The bathroom floor is ceramic tile right over the concrete slab.

What's the best way to go about doing this without causing too much damage or destroying enough of the bathroom tile that the damage will be visible even after placing the new toilet? Or is that a given? I have a rotary hammer, a sawzall with diamond abrasive blades, a circular saw with a masonry blade, and lots of other such tools.

Or is this a patently ridiculous idea and I should just get a 10" rough-in toilet?

  • Do you know what direction your exit is?
    – DMoore
    Jan 27, 2015 at 4:49
  • I am almost positive it is straight back because there's another toilet right behind it on the other side of the same wall and a plumbing vent extends up from the wall between them.
    – iLikeDirt
    Jan 27, 2015 at 5:05
  • Did you check the Toto line of toilets? In my experience you will not end up covering what you hope if you demo enough to move the toilet 2" even if you cut enough floor just to use a 2" offset flange, if you can find one. 1" is easy to find, 2"???
    – Jack
    Jan 27, 2015 at 5:20
  • I am leaving this as a comment because I can't find a link. I saw an offset pedestal that mounted to the floor under the toilet. The toilet mounted to the pedestal. It did raise the toilet several inches though.
    – mikes
    Jan 27, 2015 at 11:14
  • 2
    Or is this a patently ridiculous idea and I should just get a 10" rough-in toilet? .....This! Jan 27, 2015 at 14:33

1 Answer 1


Plumbing in concrete slabs pretty much requires ripping the floor open to make any changes to it. I suppose if you chose a new toilet with a LARGE base and were very careful you MIGHT be able to keep all the floor damage under it, but that's making assumptions that you'll be able to rework cast iron pipes (not the most cooperative things) through a fairly small hole.

I'd suggest that the extra cost of a 10" would have to be quite high before it made sense to rework for a 12" - or else you should consider if you'd like to change the tile as well, so ripping up the floor is not a problem.

Edit: I suppose the other question I didn't think to ask is where the current toilet is leaking? I rebuilt a 40 year old one last spring, as it was starting to leak around the tank bolts. Replaced the rubber washers, replaced the tank to bowl seal since I had to take the tank off to replace the washers, and was out of there with a non-leaking (for, presumably, the next 30-50 years) toilet for under $10. Left the bowl in place during the overhaul, so no new wax ring, as that end fortunately was not leaking. Unless you crack the china, they generally can be overhauled to like new, or better than new condition.

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