Remodeling bathroom I cut and chisled out the slab in order to move the toilet over about a foot. That job is complete, but when do I glue on the offset toilet flange required? I am not sure exactly how thick the floor tile and thinset will be so I can't put the flange on and then patch the hole. On the other hand, if I simply extend the waste pipe up and repair the hole before attaching the flange then I won't be able to glue the flange on. I know to wrap the waste pipe with some material I can remove easily so that the concrete can't get right next to the pipe when using a regular flange. However, the offset flange makes this method impossible. Is this question clear as sewerage? Basically, when do you attach an offset toilet flange to the drain pipe? Before the slab is poured or after?