lower toilet flange with copper waste line

[turner]

tiling bathroom floor. I tore out original concrete and going to add 5/8" plywood to orginal 1/2" subfloor for deflection avoidance for tile. Original motar bed/tile higher than new 5/8" ply/1/4" backer board/tile.

It appears that my existing toilet flange is going to be a skinny 1/2" higher than my soon to be new tile floor (top of new tile to bottom of flange). I have a 3" copper waste line to toilet. I believe my options are the following when lowering flange, if others please let me know? FYI bathroom is on second story.

1. Heat flange and remove from 3" copper waste line. Cut-off ~1/2" and sweat back on. In my younger days, used to install sprinkler systems so am familar with sweating pipes. Since pipe is not exposed after tiling, will be nervous about flange to pipe leaks after reinstall. Although not pressurized, is there a way to detect leaks prior to installing tile/toilet? Another question with this method, is best way to cut 3" copper (level) with hack saw, grinder, or other?

2. Cut copper waste accordingly and install Fernco rubber coupling/PVC flange at proper height?

Lets assume that adding 1/2" cbu (versus 1/4" cbu) is not an option to raise floor height in bathroom to account for existing flange height on account of minimal transition height between hallway and new bathroom floor.

Thanks in advance,
Chris

 

[Jadnashua]

You could do it either way, but those larger copper pipes take a good sized torch, and you might just start the subflooring on fire in the process if there isn't much room (very likely). You could use the nohub connector (probably have to go to a plumbing supply store to get the right size) and go from that to a stub of pvc, then the pvc flange. This would require access from below so you could tighten up the clamps on the nohub, though. no chance of burning the house down, though.