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bobmg 02-12-2010 12:57 PM

How to anchor toilet flange to porcelain tile?
I just had porcelain tile installed on my bathroom floor. I previously extended the PVC toilet pipe so it sticks up well above the floor. I now want to cut it off and cement the flange in place so it rests on top of the tile. I asked the tiler to drill holes in the tile so I can bolt the flange through to the subfloor. He said he never does that, that plumbers just use silicon caulk to "glue" the flange to the floor tile.

Does that sound right? I don't want the toilet moving around and cracking the PVC pipe over time. But I'm also not too excited about drilling through the tile. It is extremely hard. We used the same stuff on the shower walls and it took the shower door installer a loooong time to drill small holes through it with a diamond drill bit, muttering to himself the whole time.

Thanks for your feedback.

Bob Mariani 02-12-2010 04:07 PM

The tile is cut around the flange. This flange should be screwed securely to the sub floor. Best to do it right? If you insist on a cheap work around and accept poor quality work.... you can drill the holes with a masonry bit with a hammer drill set on hammer/drill. Seems to me this toilet will now rock and roll since the height of the flange is too high.

tpolk 02-12-2010 04:26 PM

i thought the flange sat on finished floor height not flush to ff

bobmg 02-12-2010 04:55 PM

Toilet flange
The toilet flange is supposed to sit on top of the finished floor. The toilet rests on the rim that runs around the base, but the area above the flange allows for about 3/4" clearance. The flange is only 7/16" thick, so that leaves about 5/16" for the wax ring. The toilet horn projects down level to the floor, so it will be surrounded by the wax ring.

The only question is whether the flange will stay put without being screwed into place.

Bob Mariani 02-12-2010 04:59 PM

maybe some do it this way, but never saw it done. I always make it flush with the finished floor. and tile is cut around it not placed under it. If so his plumber would not be having any issue since he would have to adjust the flange with every tile job? and he would have to always screw into the tile and not the issue he presented which he never had to do this....

Bob Mariani 02-12-2010 05:11 PM

from another site on this subject:

How high above the floor level is tolerable? There is some space under the bowl. however it varies from manufacture to manufacture.


Should the flange be flush with the tile floor? in a ideal installation, yes. However, it's not absolutely necessary.

How much lower is the cast iron flange then the tile floor? If you will look on the under side of the bowl you will see a 3" horn. This horn extends down past the flange and directs the discharge past it. Also they make a wax seal with a built in funnel that does the same thing. Why jack your toilet up so it becomes a rocking chair if you can set the toilet on the tile floor, connect it to cast iron flange and have it steady?
If you still insist on retaining the oatey flange extender you could shim up bowl and set it that way. Your choice.
Answer #2 from same site

After I find out that there are no other style of flange or toilet, then I draw a circle around the flange, remove the twist and set, chip out all the tile and thinset so the twist and set will sit near level with the floor.

so from what I see here and in many hundreds of jobs.... seems you may get away with it, but it is normally and should be perfectly level with finished floor, not above it/ Now many times we do not know what finished floor will be, this is why you see shimming adjustment rings used. And if too low you will find wax seals with a tapered plastic funnel bottom to make up the difference.
So on top.. it might work it might not. And your plumber is 100% right in not taking responsibility for this installation. The tile can crack and you now blame him for your installation issue. Not fair

tpolk 02-12-2010 05:14 PM

i would drill holes thru tile to fasten straight into subfloor. If we knew before we would shim the flange the approx height of the floor to be installed. many of the plumbers i have worked with who were good at what they do would ask for ff height

oh'mike 02-12-2010 06:10 PM

I've been a bathroom remodeler for 17 years---Bob is right flange screwed to subfloor --tile cut around the flange,

You can probably make a success of screwing the flange to the tile--sure won't give you much room for the wax ring however. Do not use glue or silicone to attach the flange to the tile-Screw,that's the ticket.--Mike--

Alan 02-12-2010 06:21 PM

I would be careful doing that... just for the fact that if your screw pushes back out a bunch of thinset chunks and backerboard pieces up against the bottom of the tile it could pop off.

Not to mention, it should be watertight to the finished floor. If you drill holes through the tile and drive screws down, where do you think any leaks are going to go to?

nap 02-12-2010 06:37 PM

why did the tiler install the tile close to the down pipe anyway. If he has done a couple bathrooms, he should know to cut the tile around the flange.

Unless you had directed him to cut it around the down pipe, I would be calling him up to reset the tiles involved so they are cut around the flange.

bobmg 02-12-2010 08:01 PM

Toilet flange again
I searched the web beforehand and found the question of flange height posted dozens of times in various forums. It also is covered in a bunch of DIY how-tos. The concensus is for the flange to sit on the finished floor, although there is a sizable minority that says it should be flush with the finished floor.

This is a house I recently purchased. The toilet flange was flush with the old vinyl floor. When I ripped out the old vinyl flooring and the 1/4" underlayment, I found that water had been leaking out between the underlayment and the subfloor. I had a square yard of mold growing between them and about four square feet of rotten subfloor to replace.

Personally, I would never ever put a flange flush with the finished floor. Just think about it - the horn of the toilet only projects as far down as the top of the finished floor. If the flange sits on top of the finished floor, the horn will project into the flange. If the flange is flush with the finished floor, the horn does not stick into the flange, and you are relying soley on the wax ring to prevent leaks, which does not seem like a good idea to me. I think there is plenty of room under the toilet for a flange and a wax ring.

The tiler has been tiling for 12 years and says he has always seen the flange on top of the tile when he does new construction.

Back to my original question, my choices are to drill holes through the tile and take the risk that the tile may crack or fail at a later time, or just use a silicon caulk and take the risk that the toilet will move around and crack the PVC at a later time. Any more thoughts?

oh'mike 02-12-2010 08:15 PM

BOBMG--You have heard from three professionals that the flange must be securely screwed to the subfloor
-----However---If you wait long enough---someone will tell you to glue it down some way--

That's what you want to hear,right? so wait a bit --surely someone will tell you what you want to hear.

bobmg 02-12-2010 10:04 PM

No, I'm not waiting for a particular answer. I've got two people telling me to drill through the tile and one telling me it's a bad idea, so I don't know what to do.

jlhaslip 02-12-2010 10:53 PM

remove the offending tiles, screw the flange to the subfloor, replace the tiles to just outside the flange, re-install toilet after grouting, and use a wax ring with the plastic drip thingie.

Bob Mariani 02-13-2010 12:05 AM


Originally Posted by bobmg (Post 398966)
No, I'm not waiting for a particular answer. I've got two people telling me to drill through the tile and one telling me it's a bad idea, so I don't know what to do.

the flange is flush with the finished floor. This is what is correct. please give me the links to those that insist on telling others the wrong way to do it. And as mentioned in these posts.... doing it on the finished surface may work if your are lucky. But it may not work. With the correct installation (screwed to the subfloor) it will ALWAYS WORK! This is why this method is correct!:eek:

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