That kind that almost feels like paper. My first thought, this is an upstairs bedroom I won't be using so it would be a good place to practice, was to just paint them, but they aren't straight...gotta go. They are intact, very well-glued, I don't see why I would have to rip them off. Seems like that would make a huge mess. I need to take down and redo the painted wood molding anyway. Could I just sheetrock on top of the tiles? I have only ever sheetrocked walls before. I know I would have to have someone help hold it up.