QUESTION

I was told that my concrete slab is a post-tensioned concrete slab. What does that mean and can I install tile over it?

ANSWER

Post-Tensioning is a method of compressing the concrete with high-strength steel tendons and end plates installed prior to pouring the concrete that counteracts the natural tensile forces created by subsequent loading of people and equipment.  The stress is applied with hydraulic jacks after the concrete has hardened. Post-tensioned slabs generally have less deflection, less cracking, and in theory are more stable than traditional concrete with rebar if installed correctly.

Generally speaking, the two recommended methods for installing tile over post-tensioned concrete is TCNA F111 Non-Bonded Mortar Bed application over a cleavage membrane for ceramic tile or natural stone installations for On-Ground or Above-Ground Concrete applications.  Or TCNA F113 method over an ANSI A118.12 Crack Isolation membrane only for ceramic tile installations for On-Ground or Above-Ground Concrete applications.