Can I bond tile directly over sheet vinyl flooring?
Yes. The sheet vinyl must be non-cushion backed, well bonded to the floor, clean and free of all contaminants that would prevent a good bond. We recommend roughing up the floor by sanding. However, under no circumstances should you sand flooring if you suspect it contains asbestos, as harmful dust will result. Do I need thin-set mortar under WonderBoard? Yes, it acts as a filler and leveling bed for the cement board. InstallationWhen should a thin-set mortar be used as opposed to a ceramic tile adhesive? Most ceramic tile adhesives have very high bond strengths in dry areas, which makes them excellent for drywall installations. Yet when adhesives are exposed to water, their shear strengths are dramatically reduced. Thin-set mortar bond strengths are less affected by water. As an example, the dry shear strength for OmniGrip is 760 psi and the wet shear is 145 psi. This is why ANSI recommends intermittent water exposure only and interior use for adhesives. Ceramic tile adhesives can take
