Bathroom floor is rotted and I need to rebuild anyway. Assuming I can cut the waste pipe below the sub-floor, which I believe I can. Is there anything I need to know in particular. Cut the waste pipe, put a collar on. Extend new pipe to floor level and attach new flange fitting? What would be the proper height for the new pipe? I assume it would be the height of the subfloor plus tile? That's the part I am unsure on.

Hi SMT

Closet flanges differ in depth and makeup measurements so you'll need to measure this out carefully.

You want to figure this so that the new closet flange will sit ON TOP of the finish floor. In this way, you'll secure the new flange through the finish floor and into the subfloor for best result.

If needed, build up an area around the flange to the correct thickness and then place the flange in place and measure the pipe length needed.

Good luck!

Mark