Removing 1" of Cast Iron

[KSlark]

I'm finishing up a bathroom remodel (okay, sort of an understatement, I had to replace a pair of 2x10 joists that were rotten from an old shower leak, but I digress) and it turns out the 55 year old 4" waste pipe is now too high. It's a whopping 1" out of spec for the new Jones Stephens C40420 flange to sit on the finished tile floor properly.

What's the best way to get the waste pipe trimmed that doesn't involve shimmying in my crawl space?

I'm unsure if the Rigid pipe cutter that HD rents would work in such a small space. I've read that you can break a small amount like I need with a ball peen hammer, but that just seems like I'm inviting problems.

I have a Sawzall and angle grinder and a Dremel at my disposal.

I wish I had tackled my fear of cast iron waste pipes when the whole floor was out that bathroom instead of when I realized the flange had to be replaced. This would have been an easy project with a Fernco coupler and some PVC.

Thanks for the advice!

 

[Reach4]

Are you saying that the cast iron pipe, that you want to put a closet flange on, sticks up to inch below the floor level? The one you are looking at seems to expect the pipe 2 inches below the floor surface. http://www.jonesstephens.com/product/c40420/

There are other compression flanges that appear to expect a higher CI pipe. http://www.oatey.com/products/drains-and-closet-flanges/closet-flanges/cast-iron-closet-flange for example. I have not used them. They don't seem to post instructions in an easy-to-find place.

 

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[Standardairconditioner]

Please post a picture.

I am almost certain that none of the lead pipe flange needs to be cut (which is very soft, by the way).

I can't image how a new floor would be lower than the original one.

 

[Smooky]

If you have access I would use the angle grinder with a cut-off wheel. You may need several wheels to get through the cast iron. You can use the sawzall if you get a diamond grit blade and you have access.

 

[Jadnashua]

A snap cutter might have problems cutting a small ring off. AN alternative (if allowed, there are situations where CI is required, but not that many) might be to remove the riser from the hub below, and replace it with pvc. The cutoff wheel will work - wear good eye protection, gloves, and clothing to protect yourself.

 

[KSlark]

Thanks for the suggestions, everyone.

I ended up measuring again and again, turns out I need to remove just under 1/2". I got out the 4 1/2" angle grinder and a new Diablo blade, I had it trimmed within five minutes. (I wore full PPE, don't worry!)

The flange went on perfectly, secured it to the floor, and mounted the new toilet. 12 hours later, everything is watertight.