I have old plastic tiles in my downstairs half bath. They've been painted over and some are missing. I thought I might be able to remove them and cover the lower wall with beadboard paneling but when I started to remove the tiles, the incredibly thick and hard glue remained stuck to the plaster. Can I put up beadboard over the tiles? Should I take off the tiles and put the beadboard paneling over the adhesive? Or is there a way to remove the adhesive and then put up the beadboard directly onto the plaster wall? I'm afraid it won't lie flat if I don't remove the thick glue but trying to remove the thick adhesive seems like it will destroy the walls.