subfloor problem

fap1800

hello, i'm new to the site and was hoping that i might get a bit of advice. i just purchased my first house and i'm in the process of gutting my bathroom. the house is an old cape, built in '21 and from what i can tell, which isn't much, it still has many of the original bathroom fixtures with a few upgrades. anyway, i've got the old cast iron tub out and the surrounding shower guard and fiber board. despite discovering a colony of carpenter ants and a horrific plumbing upgrade i noticed that the subloor is almost three inches below the tile floor. there appears to be almost a two inch wetbed topped off with the strongest one inch thick mortar/cement mixture securing the tiles. the tiles are those little octogonal one inchers that just completely shatter with any amount of force, either from a chisel or hammer. i've tried an air chisel with the tank cranked to 120lbs. that doesn't work. i'm nervous about using a sledge or pick axe because i don't want to stress my kitchen ceiling any further (already cracking through the tape). i'm at a loss. perhaps drilling relief holes with a cement drill bit and breaking it out in sections? any help would be greatly appreciated. thanks.

Bonus

The guys who really know mudbeds live over at John Bridge Forum. Maybe they also know how to erase them. Good Luck.

R&D Tile

No easy solution here, if the mud is to come out, a lump hammer or small sledge will do it, start in one corner and work your way out, messy backbreaking work, wait till you get down to the wire lath.:D

Wear safety glasses and good gloves.