My basement was already plumbed and ready to be finished when I moved into the home. However, the guys imitating plumbers, not only put the toilet waste line to close to the concrete wall (a problem I have already remedied) they also put a 3" main toilet waste line. Question: Are there flanges that fit INSIDE of the 3" line or do I have to use a 4" that would fit over the outside of the wasteline and in my opinion be prone to leaks eventually? What type of flange should I use?

How close to the wall was the drain. Toilets can be anywhere from 10" to 14" off the wall depending on what you boy. Most toilet drain pipes are 3", did you assume they were 4"? You main is 4" but toilets are fine with 3" Try a 3" Oatey twist-n-set flange for PVC. Buy "Oatey" Twist-N-Set Flange at BuyHardwareSupplies.com

Thanks for your help. The toilet is off the wall 10" and yes that is OK because they do make 10 in rough ins but choices are very limited (of all big box stores I found only 1 10in rough in) I did think waste lines (at least in the basement) were 4in based on previous questions and answers. I did find one that fits inside the wasteline, do I have to glue it in or just screw it to the floor without gluing it to the inside of the 3in wasteline?

Eswaff...

It is a good idea to cement the flange into the pipe... can't hurt anything for sure!

MARK

I have different read on the Oatey, if they tell me twist-n-set then that's what I do. Plumbers may have run into failures and prefer glueing, keep in mind with this flange you'd be glueing neoprene to PVC, not even sure what glue would work.

Bob... he didn't say he was using the oatey twist and set... he said, "I did find one that fits inside the wasteline"...

If he has a twist and set type as you posted then I absolutely agree that you will not cement this flange in. If he has a simple inside flange that has no seal then he needs to cement it.. ;) Just wanted to clarify!

Thanks...

Was concrete poured directly around pipe, or was the pipe wrapped with something(cardboard, or foam wrap etc). If plumbing rough in was done correctly, then all pipes coming out of concrete should have been wrapped. I believe this is code everywhere. Look closey, and maybe try breaking a little concrete around pipe to see if it was wrapped. If it was, you just pull the wrap out, and get a 3" closet flange that glues over pipe. If this is the case, you may want to use an inside pvc cutter to cut the pipe down to about 3/8 inch below finished floor level, so that flange will set down correctly. Ive become very irritated with people not knowing how to rough in under concrete. It only makes a true plumbers job harder when we have to go in and try to make it work, with half methods.

I don't think they make a glue style flange that will fit inside the actuall pipe, Ive only seen fitting flanges that will glue into a fitting. IF I'm wrong, please let me know where to find them.

Sorry Mark, I did miss that. I gave him a 3" that fits inside so I thought that is what he was talking about.

My only concern with glueing it to the inside of the waste pipe is if anything ever happens where I need to replace it I pretty much need to break up concrete to replace that part of the waste pipe as well, rather than just removing the screws and pulling it out. If it is on the inside of the waste line, what are the real chances of water defying gravity and creeping up between the flange and waste line if it is not glued and just screwed down with tapcon screws into the concrete?

Or should I just get a flange that is an inside fit with a rubber seal on the inside so I don't have to glue?

The chances are actually quite high that water will flow back up and through the flange... believe me... ;)

If you can find a TWIST AND SET flange with rubber seal then I say you go that route. You can use a little soap or some plumber's grease (or plumber's silicone lubricant) to ease installation to the pipe.

Good luck!

Oatey also sells a flange for your situation that uses 3 stainless screws inside that ,as you tighten, they cause the neoprene casket collar to swell.