Need help replacing closet flange

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Tacitus043
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Need help replacing closet flange

Post by Tacitus043 » Sun Sep 16, 2018 9:25 am

Hi guys,

I'm in the process of re-doing the floor in my bathroom on my concrete slab house. When I removed the toilet I noticed the existing cast iron flange was rotted away to almost nothing. There was no way I would be able to get a closet bolt, or even a spanner flange on the remnants of the old cast iron. The remains of the old flange and and the oakum/lead came off fairly easily. I have a PVC repair flange that will slide inside the old cast pipe, however I wanted to ask you guys about the best way to anchor it to the slab.

The perimeter around the iron pipe where the screws would shoot down is a void filled with dirt and debris. I was thinking about filing it with some kind of concrete, then using masonry screws to hold down the PVC flange. Is there any type of concrete or filler material that works best for this? Do I need to have a gap between the concrete and the pipe so any type of expansion does not crack the pipe? Or, is there another method of flange replacement that would work better on the slab, thanks!
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Shannon
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Re: Need help replacing closet flange

Post by Shannon » Sun Sep 16, 2018 11:12 am

You can dig out that area to about 4” deep . Mix some concrete and fill the void. Press the flange into place once the Crete has set up for a couple days and use some Tapcons to anchor it down.
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Shannon
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Re: Need help replacing closet flange

Post by Shannon » Sun Sep 16, 2018 11:13 am

If you can get some concrete nails or something into the side of the old concrete that will help the patch to be secured better to it
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A. Spruce
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Re: Need help replacing closet flange

Post by A. Spruce » Sun Sep 16, 2018 11:16 am

Shannon wrote:
Sun Sep 16, 2018 11:12 am
You can dig out that area to about 4” deep . Mix some concrete and fill the void. Press the flange into place once the Crete has set up for a couple days and use some Tapcons to anchor it down.
That's about the only thing I can think of as well.
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DanM
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Re: Need help replacing closet flange

Post by DanM » Sun Sep 16, 2018 1:57 pm

The only other alternative, which is basically the same thing just no digging, would be to clean up the area and use hydraulic cement to pack it all in. Then just tapcon it down after a few days like Shannon said.

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Aaron
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Re: Need help replacing closet flange

Post by Aaron » Tue Sep 18, 2018 11:49 am

I personally would drop the flange in so it sits proud of the finished concrete floor by the thickness of the flange itself. So fill in the void with concrete, smooth and level the floor, then use an angle grinder on that cast iron to cut and/or grind it so it's level with the new floor. Then insert that flange and bolt it down with tapcons.

That way if you ever tiled the floor, the tile thickness would line up more or less with the flange and you'd have a more stable toilet.

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