I was replacing my toilet today with a new one. The old one was outdated (32 years old accdording to manufacture date.) When I pulled up the old toilet, I found the flange to be loose... the screws that attach the flange to the floor had rotted through. So I spun it a touch, and tried to screw it down with new screws... but they wouldn't grab because the wood is rotted. There's no leaking below (kitchen) so am guessing its been a small amount of water seeping into the floor over a 50 year period.

I went and got a repair flange (moves the holes out) and 2 of those holes grabbed, but the other two were still in a place where the wood was rotted.

Can I screw some thin gauge metal to the floor and then screw the flange down onto that?

I could remove a portion of the subfloor and replace it, however since this is a temporary job (bathroom is getting moved) I'd rather do this as quick and easy as possible.

Thanks