Flange Height Revisited

[Macman]

I posted a few weeks ago asking some questions regarding the purchase of a new toilet, and ended up purchasing a TOTO Drake What a surprise!

Before installing the new toilet I've been doing some work taking up a bunch of old 1" ceramic tiles and replacing the cement board. Now I'm getting ready to retile and install the Drake.

I've been reading on the forum that the flange should be mounted on top of the finished floor, but I noted when taking the old toilet up that the flange was flush with the surface of the ceramic tiles. There was a single wax ring. I'm not aware that this was causing any problems, but am wondering if I should be looking at changing the flange height before I go any further. If I do need to raise the flange, how high off of the finished floor should it be? And are there adapters to do this?

Thanks,

Dave M.

 

[Jadnashua]

Ideally, the flange is installed so that the bottom rests solidly on the finished floor - there should be NO space under the flange and the finished floor. It should be anchored to the subfloor.

 

[Sponsor]

 

[Macman]

So Jim, from your description I gather that I've had an incorrect installation all of these years. I've been in the house for 20+ years. The toilet was here when we bought it. Is it necessary to modify this flange installation before toilet installation?

 

[Jadnashua]

It's very common to wimp out when remodeling and not move the flange. When the flange is low, you may need a thicker wax ring. That also means that it will end up not getting squished much. This also means that it isn't as strong - a 1/2" cross-section of wax is easier to breach than 1/4" thickness. Most people never have a problem. If you end up with a clog and get aggressive with the plunger, you could have a blowout if the wax is really thick.

Having the flange below the finished floor also means if there is a leak, it could happen between the floor layers, and you might never notice until things are rotten.

Lots of could, would...if you can install or reinstall the flange where it is supposed to be, go for it. There are flange extenders that can be added to extend the flange height. These work, it's another potential leak point if you don't get it sealed well to the existing flange ring.

What you don't want to do, is have the flange sitting above the floor unsupported.

 

[Macman]

Thanks Jim. I'll give this consideration. I appreciate your comments and suggestions.

 

[Terry]

The best installation is to have the flange over the floor.
In the Seattle area, it almost never happens that way.

Typical would be for the plumber to set the flange on the 3/4" plywood, and then the flooring contractor puts down 5/8" cut around the flange, and then vinyl over that. If it's tile, then it's even higher.

Two wax rings are most the plumbers in the Seattle area are using in that case.

 

[Macman]

Seems odd from a layman's view Terry. If the flange gets installed before the finishing work, but it needs to be mounted on the finished floor, it seems like someone would have developed a different way to do it. Not being in the business, I'm sure there are other considerations, but they're not obvious.

 

[Jadnashua]

It's all about how many trips the plumber has to make back to the site, and when the testing gets done - it all comes down to cost and availability.