My wife and I tried to use a cement self leveling underlay on the concrete slab in our kitchen to prep for tiling 18'' tiles. Unfortunately, we did it in 2 batches because we misread the coverage and ended up with hills and valleys. In the worst spots the tile moves about 1/8''-3/16'' when pushed down on certain corners. Would it be safe to go ahead and lay the tiles? Should we try to flatten the floor more? Also, do I need to use concrete sealer before tiling?
Ansel J. ~ Anaheim, California