View Full Version : Why Raise the Flange When You Can Just Lower The toilet!!

08-24-2007, 11:28 PM
Get this:

Someone went through all the trouble of tiling their bathroom floor, replacing their toilet, and installing a new toilet flange. However, instead of installing the flange above the tiled floor, they kept it where it was--too low. Instead, they routed out the subfloor and tiled up to the toilet base. Thus, the toilet is recessed into the subfloor by about 3/8" + an additional 3/8" from the tile. So, the base of the toilet sits 3/4" below floor-level.:eek:

This strategy still failed, however, because after I pulled the toilet, I saw that the wax ring had never been compressed. So, not only did it look like crap, it leaked anyway.

I'm definitely going to raise the flange, and tile right up to it. My question is: What kind of product should I use to fill the routed-out area of the subfloor? I don't think a wood-filler would be strong enough. How about a concrete floor leveler? Bear in mind that the thinset will need to adhere to whatever I use to fill that void. How about using thinset? Or is that too deep an area for it?

It looks like there's an old linoleum floor under this subfloor and another subfloor under that. Also, the owner says that replacing the subfloor, which would require removing a lot more tiles, is not an option.

08-25-2007, 03:23 AM
What kind of product should I use to fill the routed-out area of the subfloor?

I would probably use something like regular mortar or a sand mix to fill the major part of the space, then thinset to finish it off after a couple of days.

08-25-2007, 09:14 AM
If they still have some tile, or it is available, fill the void with the same material as the floor and tile over it. Someday that toilet may have to be replaced and the odds are good that NO TOILEt will have the same footprint to cover the patch.

08-25-2007, 09:36 AM
If they still have some tile, or it is available, fill the void with the same material as the floor and tile over it. Someday that toilet may have to be replaced and the odds are good that NO TOILEt will have the same footprint to cover the patch.

I plan on tiling over the patch, regardless of the material I use. I was just wondering if you can use a concrete or mortar patch on a wood subfloor.

According to leejo, I can.

Mike Swearingen
08-25-2007, 12:30 PM
I would use cement board screwed to the subfloor. You don't want to tile onto anything but cement board anyway, especially anything wooden that will shrink and swell.
Good Luck!

08-25-2007, 05:19 PM
A medium bed mortar can be installed at up to about 1" thick (depends on brand). You might be able to do it in one layer. NOrmal thinset is only good up to about 1/4", but you can do it in layers if you let it set in between.

the flooring sandwich of who knows what in that room is asking for failure in the future, though. Also, do you have any idea what the floor deflection specs are? There's a handy deflection calculator over at www.johnbridge.com (http://www.johnbridge.com).

08-26-2007, 09:51 AM
The pre-mixed thinset I bought says you can use it for floor-leveling up to a half-inch at a time.

Since I'm just doing a quick repair on the tile, there's nothing I can do about the "flooring sandwich of who knows what." Regardless, it will at least look a thousand fold better than it did. And, they won't have a leaky toilet.

08-26-2007, 11:08 AM
"Pre-mixed" thinset is actually mastic, not thin-set at all. Not sure how well that would hold up in a bathroom floor. Tends not to hold up well in damp/wet locations.

I'd go for the medium-set mortar & tile it all in one go; or multiple layups of thinset (real thinset, not premix; preferably the latex-modified type).

If the thicknesses are convenient, though, a piece of wonderboard would definitely be easiest.

08-26-2007, 01:04 PM
It says mortar. Is it mortar or mastic?

08-26-2007, 03:06 PM
I know - but it's basically false advertising.

"Thinset mortar", in the sense that tile guys use the words (or according to ANSI standards), is portland-cement-based. So it would harden in the bucket.

The stuff you got will dry (harden when the water evaporates out), not set (chemical reaction). So it can get soft again when it gets wet; whereas true thinset, won't.



...BTW, I learned this one the hard way.

08-26-2007, 05:06 PM
mastic is organic. It molds out. Molds enjoy using it as a base for further growth. It may only create a small permanent smell coming from under the tiles. Smells to high h*ll when you demolish later.

also, mastic can re-emulsify. It doesn't always do this. But when damp, it harbors mold colonies that grow.

A portland-cement based product is not edible to critters big or small. It is almost caustic, being alkaline in nature.

you can create whatever thickness you need with a piece of CBU or tilebacker board, to which you add (portland) thinset above and below to get the total thickness you need, or you can build it entirely out of a (portland) cement mix designed to be laid as thick as what you need. The packaging on the (portland) bag will tell you what thickness that particular (portland) product can go up to and down to. If you make it thinner or thicker than what it is designed for, it fail slightly or totally, by falling apart or by cracking here and there, or by shrinking. Mixing it drier than you think is necessary is a good thing to do, because most of the water content added to a mix is to help the person spreading it be able to work with it. Your spot to repair is small, and this is a floor not wall, so you don't need the extra water that would make it easier to work with over the course of a full day.


08-26-2007, 05:28 PM
The subfloor was routed out 3/8"? So how much (thickness) floor is this toilet actually sitting on?

08-26-2007, 05:47 PM
That mastic, 1/2" thick set under tile would take months to fully dry out, and be squishy in the interim. Think about it, it stay soft in the bucket for maybe up to a year or more - that's because it can't dry out. Same would happen under a nearly impervious tile...it would dry by wicking through the wood flooring.

08-26-2007, 08:00 PM
I'm definitely returning the pre-mixed tomorrow. Will use either a sand mix or portland-based medium or thinset mortar.

Pewter: There's still plenty of other layers of flooring to support the toilet in addition to the soon-to-be-patched subfloor.

BTW, if I can't cut out and raise this flange easily, I'm going to try the waxless by Fluidmaster. The box claims it is ideal for recessed flanges. But could be another case of false advertising. If that doesn't work, Ace carries 1/2" spacers. One of those + an extra thick wax ring should seal it if the waxless fails.

08-27-2007, 04:54 AM
Eric, just F.Y.I. - There is now a pre-mixed product from Europe that claims to be not organic based and thus totally suited for showers... blabbityblabla... I had someone return the product this summer when the packaging didn't say what it was made of, and we used a portland-cement-based thinset mix that we made on site. Better be safe than sorry. However, I am interested to know more about it, asap.

Since you have lots of high level chemistry, i am sharing this with you. Maybe one day we'll know more about pre-mixed solutions that use air to evaporate h20. Like what their properties are after they dry and become solid. Maybe some new product will be somehow better.

In the meantime, let's put in a vote for certain terms to be used only in certain contexts. Right now anyone can call anything mortar, glue, cement, thinset, etc.

Actually, I think the "portland" process of making cement is only one way to make that kind of cement. At any rate, I know there is a chemical reaction happening in real cement that turns it back into stone. Cement is limestone converted (with a lot of energy) into a raw powder that "wants" to transform itself back into limestone. When it gets a bit of h20, it grabs it and releases co2 while keeping the "h" for its own purposes. Similar to how seashells are made. Since you are a chemist, you can probably restate all this more precisely in fewer words.


Dunbar Plumbing
08-27-2007, 05:53 AM
Hydraulic cement or WaterPlug. Stuff gets hard instantly and works great for toilets on tile or concrete floors.

Been doing it for years with no problems....I tell the customer they can paint it if they like. There is no rocking whatsover after that stuff hardens.

Anything else has too long of a cure time can actually drop through vibration.

Customers will use their plumbing before you get out the door when you tell them not to use it. :mad:

08-27-2007, 06:37 AM
I'm definitely returning the pre-mixed tomorrow. Will use either a sand mix or portland-based medium or thinset mortar.

What, no thank-you?

08-30-2007, 08:38 PM
It came out pretty good. I ended up tearing out several layers of old flooring, using a gallon of Jasco floor leveler, then thinset, then 1/4" Hardibacker, more thinset, then tiling and grouting.

The tiles don't match, but it would've taken weeks to special order them and the slum tenant (opposite of slumlord) is moving in tomorrow. Also, some of the other tiles have cracks in them, but I was only getting paid to fix the area under the toilet.

Turns out that all the tiles were set over 1/4" plywood with no CBU. So, they'll probably all crack in time except for the area I just repaired.

Thanks to all who gave advice here.

08-30-2007, 10:52 PM
Well, the color difference messes with my feng shui, but that's a good looking repair.

08-31-2007, 10:43 AM
After I set the toilet, most of the white got covered up anyway.

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Give us a link.