Looking to install ceramic tile over concrete basement slab, 12x12 or 13x13 tiles. Main question is how perfectly level/flat does the concrete need to be. If I put a tile down and there is some minor rocking is that no good or will the thinset adhesive take care of that.
Any rocking means the tile is hitting either a high spot or there is a low spot. Low spots can be dealt with the thin set. As long as its less than a 1/4. High spots usually needs to be ground down flat. So to answer your question , for ease of installation and the prevention of cracked tiles at a later date, floors need to be as flat as possible. If you have minor rocking with no thin set down, in some cases a larger sized trowel will do the trick. Each case is different and has to be dealt with differently. Any questions you can e mail me through my avatar and check my qualifications there. GL
