What size toilet flange and closet bend do I need?

[Lakee911]

Hi All,

I'm having trouble determing whether I need a 3" or a 4" closet bend and flange for this toilet. The low wall mount tank is marked KOHLER USA and both the tank and lid have Kohler part numbers marked K-6802. They were cast in early 1930. The bowl, which I assume was original along with the tank is marked 13/C (thirteen with a C below it) and was cast in late 1929. Most vintage toilets that I have seen online from this era are specified to have a 4" flange and closet bend. Some are even noted that a 4" x 3" closet bend will not work. I snapped an photo of the horn and it looks pretty small. What size should I use? (I have to cross a floor joist which makes 4" tough in a 2x10--steel would be involved--otherwise I'd just use a 4" drain and call it a day).



I'm also not sure of the rough in. When I re-installed the original flush ell, I measured 14-5/8" from the back of the tank to the centerline of the horn. Can I just shorten it up by 3/4" or so and install it on a 14" rough in? I hate to plumb up a non-standard rough-in and have problems in the future if the toilet is changed.

Thanks,
Jason

[Gary Swart]

First of all, your closet bend has to match the drain pipe size, not the toilet. The flange has to match the closet bend. The top of the flange is the same size for all. Your toilet is a 14" rough-in. The fact that your flange measures an extra 5/8" just means the toilet will sit 5/8" further out into the room and have that much extra space behind the tank. Toilet come in standard rough-in sizes of 10", 12", and 14". Only a few models choices are available in 10" and 14" because 12" is the basic standard rough-in. Toto makes an adapter for a few of their models that permits these toilet to install and any of the 3 rough-in sizes, but these adapters only work on these specific models. My question to you is why in God's name are you installing an 85 year old toilet. This is most likely a 7 gallon per flush monster with obsolete repair parts. I note by the number of posts you have made that you have been around this forum for a long time and surely should know there are far better choices for toilets that are not expensive and will perform well on 1.28 or 1.6 gpf. If you were restoring a vintage automobile, I might understand why you needed vintage parts, but toilets are another matter. Maybe I'm missing something???

[cacher_chick]

Dump the toilet and install your plumbing for a 12" rough-in. Every store in the country carries toilets for a 12" rough, and only a few carry anything else, and then you will pay plenty extra for it.

[Terry]

You can use a standard 4x3 closet flange and 3" pipe for that.

Of course 4" is an option too. So, pretty much whatever you feel like working with.
Most new toilets have about a 2" trapway, much like the bowl you have now. Though we also pull out some that look to be 1.5"
Caroma is the only one I know of that has both a 3" trapway, the 305 bowl and one with 4" at the outlet, the 270 bowl.

[Lakee911]

Thanks for the replies!

The fact that your flange measures an extra 5/8" just means the toilet will sit 5/8" further out into the room and have that much extra space behind the tank. Toilet come in standard rough-in sizes of 10", 12", and 14". Only a few models choices are available in 10" and 14" because 12" is the basic standard rough-in.

If I install it on a 14" rough, the tank is going to be sitting in the wall, not away from it, by 5/8". Seems more like it would be a 15" rough. If I can shorten up the flush ell (wall mount tank), I might try to get it into a 14". I understand that 14" is uncommon but 15" is virtually impossible. I don't want to completely screw the next person who comes along, if I can help it.

My question to you is why in God's name are you installing an 85 year old toilet. This is most likely a 7 gallon per flush monster with obsolete repair parts. I note by the number of posts you have made that you have been around this forum for a long time and surely should know there are far better choices for toilets that are not expensive and will perform well on 1.28 or 1.6 gpf. If you were restoring a vintage automobile, I might understand why you needed vintage parts, but toilets are another matter. Maybe I'm missing something???

I live in an old house, Gary. We're putting in a new bath and we're using almost all salvaged or period appropriate parts where we can. My sink is from 1928 if that makes you feel any better (or worse). In this case authenticity trumps efficiency. This toilet will not see a huge amount of use. Our half bath, which gets the majority of the use, is a 1.6gpf toilet and when the toilet in the other bathroom breaks it will be replaced by a Toto--I'm a big fan of Toto toilets.

Dump the toilet and install your plumbing for a 12" rough-in. Every store in the country carries toilets for a 12" rough, and only a few carry anything else, and then you will pay plenty extra for it.

I understand where you're coming from. Actually there isn't too many parts on this sucker that are that uncommon. Douglas flush valve is common, fill valve is standard. The biggest thing is the flush ell and I think that if the original one lasted 80 years, the next one will likely last nearly the same.

You can use a standard 4x3 closet flange and 3" pipe for that.

Of course 4" is an option too. So, pretty much whatever you feel like working with.
Most new toilets have about a 2" trapway, much like the bowl you have now. Though we also pull out some that look to be 1.5"
Caroma is the only one I know of that has both a 3" trapway, the 305 bowl and one with 4" at the outlet, the 270 bowl.

Well, I feel like working with 3" but what I'm concerned about is that so many toilets from this era are noited that they need to be 4". It would be a lot more work to go 4" here as I have to cross a joist and I'll likely be using some steel in that case. Maybe it will help to know why 3" became so popular...used to be all 4" right? Was 3" even an option in 1930?

FYI, this is one of the locations that show most older toilets needing 4" ... http://deabath.com/Original/Or_Toilets/or_toilets.html

Thanks everyone!

[Lakee911]

I exchanged a couple of emails with John V. from Bathroom Machineries (http://www.deabath.com) and asked about the 3" vs 4" issue. He responded as follows:

Yes, the older bowls have to have the 4" flange. If you use a 4x3 reducing flange, there usually isn't enough room for the wax ring. Go with the 4x3 closet ell.

I'm going to go to blue box store tonight and compare flanges...sounds like a 3" flange is smaller than a 4" flange. I always thought a flange was a flange was a flange...apparently not.