View Full Version : 4x3 inch closet bend or 3 inch closet bend?
07-12-2005, 07:09 AM
I am installing a new flange and closet bend in my bathroom remodel project. I bought a 3 inch closet bend with a 3 inch flange and also a 4x3 reducing closet bend,and a 4 inch flange. What is the best one to use? Is there an advantage to using the larger one? The waste stack is three inch.
master plumber mark
07-12-2005, 04:10 PM
the three inch one is common and pretty
simple to install and works ok....
if you got the 3x4 inch and you are going to put a 4
inch flange on it it is ok too...
the 4 inch one just gives you a little more clearance as
the water leaves the toilet....
with probably less a chance of
water seeping back through the wax ring some day...
I guess that is why they are made,
at least it sounds like I know what I am talking about,,,
I may be in the minority, but I have NEVER used anything other than a 4x3 closet bend.
07-12-2005, 06:33 PM
FWIW, the company with about the biggest trap sizes in a toilet readily available is probably Toto with 2-1/8", so anything bigger than that for a flange size would prevent a backup as long as the drain was not plugged. A good toilet design probably fills that trap during at least part of the flush. Area, remember is related to the square of the radius, so a little additional diameter really increases the total area. My unprofessional opinion.
master plumber mark
07-12-2005, 08:51 PM
I have never used anything but a 3x3 flange,
literally thousands of them.....no problems
The only advantage of the 3x4 I suppose would be
the extra room for the water to pass through without
putting pressure on the wax ring...????
or is it to minimize the possibility of stoppages at the entrance to
does it make things easier on the venting??
what else could it be to even use the 4x3 these days??
is it just some tradition that has hung on from the days when
4 inch cast was used exclusively??
07-15-2005, 07:52 PM
I thought I had purchased a 3 inch closet bend, but I can't find it. I went to the Home Depot and also Lowes looking for one, but it seems they only have 4 inch closet bends. Can I use regular 90 degree elbow for the closet bend? How about a long sweep 90? What is the difference between a closet bend and a regular 90 degree fitting? They look very similar to me.
It has absolutely no effect on the venting. One advantage, someday, is that you have more options to retrofit a new flange, if needed, with the 4" than with the 3".
07-15-2005, 09:05 PM
HJ has a good point, with a 4" drain line, there are flanges that fit inside the pipe rather than having to fit outside. But, unless it is in a slab, under normal circumstances (is there such a thing?!), they rarely go bad, and if you are remodeling, a new one isn't that big of a deal.
07-19-2005, 08:50 AM
Well, I figured I would tag onto the end of this thread instead of starting a new one since the subjects are so similar. I am doing a bathroom remodel of a 1950's tract home in So. Cal. with a raised foundation. I am replacing all of the original steel and cast iron DVW lines with black ABS. The main line had been replaced a few years ago with ABS and the remaining steel and CI was tied in with flexible couplers. I figured since the walls and floor were open there was no better time to replace the old with new. Good thing too since two threaded joints snapped with only a little effort.
OK, to the point. I went to Home Depot to get parts and they did not have anything labeled as a closet bend. They had what was called a 4x3 street ell that looked just like the ABS closet bends I have seen in online catalogs and the guy there said that was the correct part. However, I don't trust the floor workers at HD all that much. A 4x3 closet flange fits in the 4" side of the ell but is a bit loose at first and then seats at about 90% of the depth. Now the questions;
1) Is this 4x3 street ell the correct part or should look for something actually labelled as a closet bend?
2) Assuming the part I have is correct, should I rough it in so that the flange is installed directly to the closet bend or should there be a piece between the flange and the closet bend? We are doing a tile floor so I intend to leave the flange for last so it mounts on top of the tile.
Hope this all makes sense and thanks in advance.
If the 4" riser is the "street" side of it, then that is a closet bend. The proper flange for it fits over the street side and slides down onto the floor, then you cut the excess riser off flush with the flange.