[trekkor]

Custom's Versa-Bond is a higher quality thinset with polymers in the mix that are water activated.

For the best performance use a seperate acrylic admixture in place of water with a premium thinset designed for acrylic.

Porcelain tile will not bond properly ( fail ) with a water mixed mortar.

Also, check that slab for cracks, surface depressions or rises.
Make your corrections before laying a single tile.
Is looks like there is some wall compound staining on the cement as well.

If you want this floor to outlast every surface in your home, give it a good acid washing followed by 1-2 rinses.


KT