As part of a remodeling effort, we are having a tiled shower built in our guest bathroom. We had a plumber come out to run the water and drain lines. He installed the drain.
Last night I noticed that the hole he cut in the plywood sub flooring is quite a bit larger than the drain, so that there's nothing supporting the drain except the pipe.
I called the guy and he said that that is the way the tile guys want it so it is flush with the floor. This makes no sense to me since there are several layers of mortar, liners, etc, before the drain top goes on.
I don't know a whole bunch about this stuff, but I think this guy just screwed up and won't admit it. I'm telling him to come back out and replace the sub flooring and cut the hole just big enough so that the drain flange is resting on the floor. He's not too happy about it.
Another option is to fit and screw two semi-circled metal doublers around the hole and let the drain flange rest on it.
Am I way off base with this? What this guy is saying just doesn't make sense to me.
Thanks.

Hey Dawg,

Let me tell you how it goes. The traps 2" raiser comes up through the sub floor through A HOLE CUT TO SIZE. This means the hole is just large enough to allow the raiser and pipe section of the shower flange to come through . The bottom half of the flange type shower drain,(see image) sets on the floor for support and a vinyl shower pan's installed. Then the top half's bolted down on top to make a water tight seal. I don't hear any mention of a shower pan that the plumber should have installed. You got a inexperienced/ incompetent plumber. The flange MUST BE SUPPORTED in order for the tile man to complete the tile work.
You may have to get a carpenter out there to repair the damage the plumber has done but I wouldn't let the same plumber back in my house. Good luck, Tom

Thanks. That's what I thought. I just wanted to make sure that I wasn't totally missing something here.
We actually have a guy that will build up the rest of the shower, including the tile work. All this plumber was supposed to do is run the water and drain lines. I'm not sure what he was thinking on the hole, but my wife seems to think that he first cut the hole off-center and then just wallowed it out to line up with the drain line. Who knows.
I agree with you, that I probably shouldn't let this guy back in. Do you think my idea of installing a metal doubler to cover up the hole enough to just allow the raiser to come through the floor would work?
Thanks for your help.

"All this plumber was supposed to do is run the water and drain lines."
This includes panning out the shower, running a inch or so of water in the pan and letting it set to test for leaks. This was done wasn't it? If not then you have a case against the plumber and his company for shoddy workmanship. You do live in the U S don't you? I'm not being a smart a$$ but as a rule here in the US tile men don't pan out showers or set flange type shower flanges. Get someone in that can do the job right.

"Do you think my idea of installing a metal doubler to cover up the hole enough to just allow the raiser to come through the floor would work?"

Has the flange been installed yet? Regards, Tom