Sounds like you know your flooring! But here's the thing, whoever put this floor down 20 something years ago laid a sheet of plastic over the particle board, then a sheet of chickenwire, then 20mm of cement...... then laid the tiles on top of all that. So the good part is the whole layer of cement and tiles is kinda floating on that layer of plastic like a huge biscuit, but is hard as #### and needs to be broken up somehow so i can shovel it all out.