What are the benefits to allowing a sufficient cure time for the concrete?
Clearly, the longer you can wait before tiling, the less stress that will be applied to the tile by the concrete. Also, should the concrete crack, the crack can be treated (with an anti-fracture membrane) before it is tiled. If curling occurs (and it often does), the concrete can be ground before it is tiled. Tiling before the curling occurs can cause undesirable debonding of the tile and lippage between adjoining tiles. What if I can’t wait 14 to 28 days for the concrete to cure? If you really can’t wait 14 to 28 days, you may want to consider a vapor equalization membrane. Reportedly, this membrane isolates the tile layer from the concrete layer but still allows for the vapor to leave the system. This is different from a crack isolation layer that may not allow the “green” concrete to breathe.
