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mizzoualum · Sep 20, 2006, 06:58 AM

I am remodeling a bathroom in an old house. The floors are concrete, and right now there is just what looks to be a cast-iron waste line that runs up through the concrete for the toilet. The inside opening of the pipe is 3 1/2" in diameter. What flange do you recommend for this? I can only find 3" or 4" - one is way too big and the other is way too loose. Please help - Thanks!
Matt

speedball1 · Sep 20, 2006, 12:05 PM

Originally Posted by mizzoualum

I am remodeling a bathroom in an old house. The floors are concrete, and right now there is just what looks to be a cast-iron waste line that runs up through the concrete for the toilet. The inside opening of the pipe is 3 1/2" in diameter. What flange do you recommend for this? I can only find 3" or 4" - one is way too big and the other is way too loose. Please help - Thanks!
Matt

Hi Matt,

Give me the outside dimeter of the soil pipe. Regards tom

mizzoualum · Sep 22, 2006, 09:04 AM

The outside diameter is around 4 1/2 ", but I should mention that the pipe is embedded in the concrete floor, so there's no room to fit something around the outside of it. Any ideas? Thanks!
Matt

speedball1 · Sep 22, 2006, 10:58 AM

There are flanges made to install inside the cast iron pipe without having to chip up the cement around the pipe.
Click on; http://www.plumbingsupply.com/toiletflanges.html
And scroll down and check out "Expansion Flanges".
Good luck, Tom

mizzoualum · Sep 25, 2006, 01:53 PM

Tom,
I visited this site, but the smallest expansion flange I could find was 4", which is still too large. Any other ideas?
Thanks,
Matt

speedball1 · Sep 25, 2006, 04:41 PM

Originally Posted by mizzoualum

Tom,
I visited this site, but the smallest expansion flange I could find was 4", which is still too large. Any other ideas?
Thanks,
Matt

I'm confused Matt,
Number one, Service Weight cast iron comes in 2, 3. 4 .5 .6 and up. There isn't a 3 1/2" ID cast iron pipe. I'm taking my readings from The Cast Iron Soil Pipe and Fittings Handbook by the Anniston Foundry Co.
The pipe that you have is 4" ID cast iron with a OD of 4 1/4". Not 3 1/2" ID with 4 1/2"OD. Do you realize the size of the pipe walls, ( !/2" walls)The heaviest cast iron pipe made, (XH Extra-heavy) only has 1/4" walls. So I can't buy your measurements. I stand by my recommendation, If you don't want to chip out the cement from around the cast iron pipe and lead in a regular cast iron flange you will go with the 4" inside expansion flange I recommended. Regards, Tom

garyfisherz · Jun 28, 2012, 10:12 AM

I'm having the same thing as matt here the cast iron pipe in the concret floor has an inside diameter of 3.5 inches its one of the old pipes with the bell shaped fitting on the ends and that's what's coming through the floor is the bell fiting the bacement of this house is about 50-60 years old with a newer upstairs built on and I'm trying to redue the bacement bathroom and can't find a floor flange to work because its eather too big or too loose

advproducer · Jun 21, 2013, 12:45 PM

I've got the same problem and hopefully a couple of years later somebody has figured this out. I have attached a photo which shows that the pipe is actually 3 1/2" ID to prove to people that I'm not crazy (because I've been getting the same reaction from everyone as speedball1 had) Anyway, any help would be very much appreciated! -Greg

massplumber2008 · Jun 21, 2013, 01:39 PM

Hi ADVP

You have a 3" extra heavy cast iron pipe there.

You can try a local plumbing supply house and see if they sell a 3" closet flange that will expand against the inside wall of a 3" pipe, but I doubt it.

Most likely, you will need to chip up the concrete from around the pipe and then install a 3" cast iron flange (will need to be leaded in) over the pipe. Depending on the floor finish you may need a deep flange.

They also make 3" compression flanges, but they are only 2" deep and I don't think the seal will be in the right place for you in the end (in relation to your finished floor).

Be clear that the new flange needs to sit ON TOP of the floor tile, OK?

Back to you...

Mark

Mike45plus · Jun 22, 2013, 07:05 AM

Sioux Chief makes a gasketed flange & extension that fits inside 3" cast iron or plastic soil pipe. The gasket is similar to a Fernco doughnut, and is tapered to form a water tight seal when push - fitted into place. There are a variety of rubber doughnuts available from Fernco, that could be altered or shaved to fit, if the gasket that comes with the flange kit does not fit.
The flange should be fastened to the floor with screws and anchors before installing the toilet...