Can I put plywood over an old subfloor?
There are two potential problems in installing self-stick tiles over a subfloor. One is the smoothness of the subfloor. To be blunt, the floor should be absolutely smooth! The reason is because any irregularities.. lumps, bumps, seams, nail holes, etc… in the subfloor surface will be transferred through to the tiles over time. This is true of vinyl tile installation over any surface. Even the pattern of a textured sheet vinyl or linoleum floor will appear through the self-stick tile! Now if you are only talking about a imperfections or nail-heads, these can be easily repaired by patching with a quality wood filler or floor leveling compound. Don’t use wallboard patching materials because they may not be hard enough. Sand surface smooth, vacuum and damp-clean to remove all dust before tile installation. The second problem is at the seams of the floor. If there is any “flexing” or movement at the seams, the tiles will eventually crack across these seams. In most situations, the easiest
Everybody has really good points, but I would definitely put hardibacker on the floors you will tile. Plywood is not enough. I know this from experience, and I had a so-called professional tiler do the job. He tiled over plywood floor in a small bathroom and within 2 weeks, the grout starting coming out and tiles were popping like crazy. There simply is too much movement on a wood floor. We ripped everything out, had hardibacker put down and re-tiled with new tile too (what an expensive lesson that was!) and we haven’t had any problems at all.
