View Full Version : 5" inside diameter toilet flange - cast iron

11-28-2004, 10:38 AM
I have a 5" inside diameter toilet flange that's 1 1/2" deep that's connected to a 4" inside diameter cast iron waste pipe. The problem is wax rings are made for 3" and 4" openings. Is there a wax ring for a 5" opening or what do you recommend to reduce the opening to 4"?

Ken - Chicago, Il

11-28-2004, 01:33 PM
A regular wax should fit. The inside of 4" or 4 x 3 flanges are almost five inches. I have not hear of a 5" toilet flange.

11-28-2004, 03:03 PM
Although I never had this problem...
Instead of reducing the (closet flange) drain opening you would be better off combining a small section of a second wax seal to another one to make the diameter larger if that's what you need to do.

11-28-2004, 07:15 PM
Apparently the 4" cast iron pipe is not long enough to reach the surface of the flange, the way it should. A plumber would caulk a section of pipe inside the flange so the new opening would be correct for a wax ring.

11-29-2004, 06:44 AM
What type of pipe do you recommend caulking in there? What will fit? A piece of iron pipe or PVC? I think if I reduced the opening down to an inside diameter of 4", the wax ring would give me a better seal in the long run so I don't have to repair the floor again. The plumbing guy at local Home Depot said this might be a commercial fitting that was put on my toilet.

I just talked to a commercial plumbing supply house. Apparently my situation is common plumbing technique in the Chicago area. The flange is 5" diameter with a 1 1/2" drop connecting to a 4" waste pipe. A regular wax ring should do the trick. Apparently, the original installation had a plumber's putty like consistency that reduced this 5" opening to about 4" (this material was very stiff and flaking) when I originally removed it.

11-29-2004, 12:14 PM
The "5"" flange is really a 4" one, but the 4" pipe is too short. The best solution would be a 1 1/2" piece of cast iron pipe caulked, (leaded), into the flange to raise the 4" to the finish floor elevation. Failing that a piece of 4" ABS or PVC could be inserted and siliconed in place so it lines up with the existing 4" pipe.