External vs Internal Cast Iron pipe closet flange

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thenextdon13

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Hello-
I've searched a bit and only found this thread, which is actually a lead closet arm.

I have a 4" cast iron closet arm. The flange was far over the surface of the floor, causing leaking issues on the toilet. I'm installing new flooring, underlayment and one layer of subflooring-- and want to use a modern flange that screws to the floor and I can easily adjust level of in the future.

I removed the flange (thanks to help from reading this form, thanks Terry for having it) and am trying to decide whether to use an internal vs external flange.

The internal flanges have a smaller ID, which somewhat worries me. I've been looking at these two Oatey products
Internal:
http://www.oatey.com/products/drains-and-closet-flanges/closet-flanges/replacement-closet-flange

External:
http://www.oatey.com/products/drains-and-closet-flanges/closet-flanges/cast-iron-closet-flange

Any thoughts on benefits/drawbacks of External vs Internal?

My only thought is that the internal would allow for the floor to be closer to the pipe, insures wastewater enters the pipe without ever hitting the seal-- but would also have some restriction on the flange.

The external flange seems more robust and has no restriction, but the seal is on the outside of the pipe which somewhat worries me.

I guess the wax rings have a flange that directs wastewater into the pipe so it should theoretically never come in contact with an external flange...

Any thoughts/opinions appreciated.
Thanks!
 

hj

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I have been doing this for over 60 years and have NEVER used an "internal" cast iron flange. I also do NOT use the wax ring with the "funnel that directs waste water into the pipe".
 

Gary Swart

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A flange should rest on top of the finished floor and be screwed through into the sub floor. The external fitting flange should be always used, but an internal fitting flange can be used if the closet bend is 4", but never with a 3" bend. If the flange is fit as described above, the wax ring should be a standard ring without the plastic funnel.
 

thenextdon13

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Thank you for the pointers and help-
One other question; I've read it is good to clean up the cast iron with a wire brush before installing the flange.
After that, do you lubricate it with anything to help the rubber slide, or to keep it from corroding?

I'll have to look more closely at how the external compression flanges work with the wax rings to get an idea of how the liquid/waste flow goes.

Thanks again!
 

surfsalterpath

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Same issue. I removed the OLD oakum/jute/lead flange that was TOO HIGH off the floor for these new toilets----which do not have enough depth lip as the old toilets. The waste pipe is 4" cast iron in vry good shape BUT was too high. Had to GRIND off about 1/2" of the jagged top of the 4" cast iron waste pipe installed in the '60s. So my alternative is the external 4" compression flange I saw used on a 'this old house' youTube clip and I'm going to try this waxLESS seal from FERNCO:
http://www.fernco.com/plumbing/wax-free-toilet-seal Any of you guys ever used this particular waxLESS seal? Thanks!!
 
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