11.5" rough in , which 12" rough in toilets can I use?

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Donn Bialik

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I am building a bathroom in my basement, and for whatever reason (me!) the actual rough in on the toilet flange is 11 and 3/8" from drywall to center of toilet flange. My hunch is any 10" rough in toilet is going to create a large gap between back of bowl and wall. Do all 12" rough in toilets have at least an inch between back of bowl and wall? If so I could use any 12" rough in toilet. I don't install enough toilets to know this.
toilet.jpg


Any advice?

I'd like to buy a toilet from a big box store so I can return it if it doesn't work.
 

Reach4

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Most plan for 1/2 to 7/8 inch. However things can cause that actual to vary, including the wall and floor may not make perfectly right angles. And then there are manufacturing tolerances.

Fortunately, there is some adjustablity/slop in the installation process, and you can get some variation of maybe plus or minus 3/8 or better in the direction that you want. Using 1/4" rather than 5/16" closet bolts gives you an extra tiny bit of adjustability.

Most toilets will fit your space well.

I am concerned by your closet flange ring floating. The plan may be that flooring will fit just right as it is slid under that ring. There should be material below the metal ring, and there should be screws through the ring to hold the ring down. Screws pull down, and the material under the ring provides any upward force needed.
 

Donn Bialik

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Most plan for 1/2 to 7/8 inch. However things can cause that actual to vary, including the wall and floor may not make perfectly right angles. And then there are manufacturing tolerances.

Fortunately, there is some adjustablity/slop in the installation process, and you can get some variation of maybe plus or minus 3/8 or better in the direction that you want. Using 1/4" rather than 5/16" closet bolts gives you an extra tiny bit of adjustability.

Most toilets will fit your space well.

I am concerned by your closet flange ring floating. The plan may be that flooring will fit just right as it is slid under that ring. There should be material below the metal ring, and there should be screws through the ring to hold the ring down. Screws pull down, and the material under the ring provides any upward force needed.
I almost mentioned something about that. The floor is self leveling concrete. On top of that will go thinset, then Ditra Heat Duo, then thinset and tile, so the closet flange hasn't been officially placed yet. The flange will sit flush on the top of the finished tile.
 

Donn Bialik

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Most plan for 1/2 to 7/8 inch. However things can cause that actual to vary, including the wall and floor may not make perfectly right angles. And then there are manufacturing tolerances.

Fortunately, there is some adjustablity/slop in the installation process, and you can get some variation of maybe plus or minus 3/8 or better in the direction that you want. Using 1/4" rather than 5/16" closet bolts gives you an extra tiny bit of adjustability.

Most toilets will fit your space well.

I am concerned by your closet flange ring floating. The plan may be that flooring will fit just right as it is slid under that ring. There should be material below the metal ring, and there should be screws through the ring to hold the ring down. Screws pull down, and the material under the ring provides any upward force needed.
So you're saying that you typically see a gap between 1/2" and 7/8" of an inch between back of bowl to wall on most toilets?

That's good news.
 

Paulypfunk

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Don’t put your heat cable too close to the toilet flange, and I’d recommend using a neoprene or other non bees wax toilet ring. Your floor heat system can melt the sealing wax and cause the toilet to leak underneath.

A 12” rough in is the measurement from the center of the outlet pipe to the beginning of the wall studs. The fact that you have drywall and such is factored in. Most toilets will fit fine. If you really want to check you can go to the manufacturer and look up the dimensions of the toilets. Almost always they list the distance from the bolts to the back of the tank.

Correction:
A 12" rough is measured to the finished wall, not the stud wall.
Manufacturers will have a spec sheet that will show how much space there is between the tank and the finished wall when the toilet is set 12" from the finished wall. Much of the time you will have 1/2" and sometimes up to an inch depending on the tank model. This started changing in the mid 1980's when things like wainscoting and tile on the wall behind the toilet started to interfere with the standard rough-in's. They changed the molds and planned for more space.
 
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Donn Bialik

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Don’t put your heat cable too close to the toilet flange, and I’d recommend using a neoprene or other non bees wax toilet ring. Your floor heat system can melt the sealing wax and cause the toilet to leak underneath.

A 12” rough in is the measurement from the center of the outlet pipe to the beginning of the wall studs. The fact that you have drywall and such is factored in. Most toilets will fit fine. If you really want to check you can go to the manufacturer and look up the dimensions of the toilets. Almost always they list the distance from the bolts to the back of the tank.
Bro, thank you SO much for the advice on the heated floors. I've done lots of bathrooms, but they were all in Los Angeles, and never with heated floors. No bee's wax!!!!
 

Reach4

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I've been looking at those. Most seem to be 1 3/8" gap. Probably going to get that Entrada actually. Thanks!
Look at the dimension between the top of the tank and the wall, rather than the space between the base and the wall.
 

wjcandee

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Whoa. STOP. A rough-in is correctly-measured from the finished wall to the center of the closet flange. Not from the studs, contrary to what one (otherwise-excellent) post in this thread says. Sorry, but that's the official, actual, architectural truth.**

Now, that said, many 12" rough-in toilets don't use the whole 12 inches. They're just saying that they will fit on a 12" rough in. And the few that do require the whole 12" usually make that very clear on the spec sheet, often in capital letters. But some do. Most, as noted above, have a little play, or even more-than-a-little play.

Donn, you are misreading those spec drawings, so I would stop and follow Reach4's advice to reread them or you're going to end up in tears.

Usually, the most-important (i.e. smallest) dimension is from the tank top to the wall, or from the protrusion towards the wall that is directly under the tank. If you just look at the base, you're going to have a base that fits fine, while you're slamming the back of the toilet against the wall finding that it won't fit.

The classic toilet that has significant space between it and the wall is the original Toto Drake with the original tank, Model CST744E, which can fit on just-less than 11". Many people really like that Entrada that you mentioned, as well, and it's a good value, but make sure you have the room.

Also recognize that toilets are made out of clay and baked in a kiln. Some brands use better clay than others in terms of the consistency of their water content and thus what the "baked" size will be. Toilets shrink dramatically in the kiln from the formed clay to the final product. Like 15 percent or more. That's enough that if they don't shrink consistently, the output will vary. Toto is the most-consistent in terms of clay, and thus the most-consistent in terms of finished size. Toto is also the most-consistent in terms of the finished product not varying by factory. You can have a Toto bowl and tank made in Atlanta and a Toto bowl and tank made in Vietnam, and you can mix and match and never be able to tell where one or the other came from.

But because you're dealing with something where some are going to be bigger than others, I wouldn't put myself in the position of needing every 1/8" on the spec sheet. Similarly, I wouldn't put myself in the position of wanting to be sure that the toilet has no space between it and the wall. You're going to find that, out of the box, you can't completely count on either. Somewhere on most sheets it will explain that one should expect variation from toilet to toilet to toilet of the same model from the same factory. Because an experienced installer can cheat the toilet a little towards the wall or a little away from it, this helps some to get you the look you want.

Bottom line: read the spec sheet carefully, and be sure you have enough room. You should be able to find a toilet you like that fits.

That looks like a very-nice job you have done so far, so we would love to see a photo of it when you're completely-finished! And don't hesitate to come back in the interim.


**For reference, in case people don't trust New Yorkers:

About Toilets (americanstandard-us.com)
 
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Donn Bialik

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Thanks, everyone. I was being lazy and simply looking for a pro to recommend a good toilet that they knew had a some play. I've ordered a Toto from HD and based on the spec sheet it should fit no problem. If not, at least returning it is fairly easy.

WJC - My understanding has always been that rough in was finished wall (not counting base) to center of closet flange. My error was when I set the flange I forgot to add the 1/2" for the drywall. Anyway, I'll be sure to post some completed photos. Just finished mudding and taping, and setting my door, so hopefully I'll be tiling in a week.

Thanks again for all the help!
 
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