Ask Me Help Desk - ABS closet flange install

I searched for a while and couldn't find my answer, so please bear with me if this has been answered before.

I am finishing a bathroom in my basement, and it is time for the closet flange install. I have a 3" ABS drain pipe sticking out of the floor for the toilet. I have the tile finished,and was planning on setting the flange on top of the tile.

My question, I went to purchase a flange (ABS) and the guy at the plumbing store told me it was a bad idea to use a flange that glued inside my 3" pipe, because I was setting myself up for problems with a bottlekneck like that. He suggested I use a flange that slips over the 3" ABS. Is chipping out the concrete around the pipe for this arrangement worth the time, or is using the other style flange not that big of a deal?

Thanks!

BM

Quote:

the guy at the plumbing store told me it was a bad idea to use a flange that glued inside my 3" pipe, because I was setting myself up for problems with a bottlekneck like that.

If a inside flange's so bad it kind of makes you wonder why they stock and sell them doesn't it? In my area when we rough in a toilet on a slab we always wrap a plastic "closet Wrapper" around the stubup to give a5/8ths inch clearance around the pipe so a outside flange can be mounted. Sometimes the concrete guys will over pour the wrapper so it looks solid. But it's only skim so tap around the pipe to see if you have one installed. If you do then dig it out and install a outside flange.
If you don't have it I would install the inside flange. Since the throat of the bowl chokes the flush down the 2 5/8ths. Inch before it ever leaves the bowl I think you're going to be just fine. Good luck, Tom PS. That's why big box plumbing salesmen aren't out there doing plumbing..

Hey BM...

Ideally, when concrete was poured the plumber sets a foam band or a can around the pipe which is later removed, the pipe is cut and the closet flange is glued and set. However, as you see, this does not always happen.

The fact is that if you look at the bottom of a toilet bowl you will see the actual "bottleneck"....here, there is a 2.5" rimmed hole that sets down into the closet flange. So whether a 3 inch or a 4" closet flange and whether inside or outside pipe seems to make no difference in the long run.

What does make the difference is that a vent was installed for the toilet and that the pipe has pitch and toilet gets installed properly so the wax gasket does not intefere with drainage!

If plumbing is installed correctly then I think you will be just fine setting an inside TWIST AND SET TYPE closet flange (available at home supply houses and plumbing supply houses)... see pics below.

In the long run I say you go for it and set the flange and the toilet (I use a horned wax gasket and 5/16" johhni bolts)... best way to secure the flange is by using an anchor kit like in my other pic. Below (drill bit comes with kit). And then test it... if all OK... and it will be... great! If not, can always pick it up and start again... that is the nice thing about the twist and set... can also pull it out... ;)

Let me know what you think... MARK

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TOM...that's a riot!! I was writing as you posted. Always nice to see we agree!!! Good day!

Thanks for the quick answers guys! I think I will try the twist and set inside flange, and then redo it if there is a problem. I am not sure of the venting on the toilet as everything is in the concrete. Also, they did not install a closet wrapper. I have chipped the concrete down approx 3/4" already and it is all solid.

The sink drain has a vent that goes up and out of the basement, and I am almost sure that the toilet and tub drain are all connected to the toilet drain. Like I said before, I cannot be certain as it is all under the slab. Speaking of the home depot plumbers: I don't think they know anything. That is why I come ask you guys!

The one yesterday got pretty agitated with me because I was deciding between a flange with the test cap knock out and the one without it. I told him that I probably didn't need the test cap because I was pretty much ready to install the toilet, and he replied "You don't use the test cap when you install your toilet anyway!" I mean seriously... Do people really install a toilet with the test cap still in place?

Thanks again guys!

BM

Let us know how it works out.. ok? Thanks!