Okay, here's the situation. We pulled up our toilet in preparation of
laying the backerboard and then the new tile floor. However, when we did we
discovered that some time in the past (had to be before we owned the house)
there was sufficient leaking around the toilet to destroy the flange and
also caused some water damage to the vinyl floor's underlayment (particle
board). 90% of that board is good a solid, but where that leak had occurred
there is some minor swelling. We had to cut out part of the flooring around
the toilet plumbing to replace the flange properly, and when we replaced
that piece that we pulled out, we find that the swelling makes the floor on
the one side of the repair about 1/8" higher than the replacement.
Questions: Must we cut out more of the particle board and replace it, or
would sanding it down level be sufficient? We intend to put backerboard
down, but because of where this is (small bathroom - can't get under the
cabinets) we don't want to have to take up the whole piece of underlayment
(particle board). I'm thinking that some elbow grease and a good sander
should level it off. Any thoughts?