Will installing a plastic vapor barrier under cork underlayment and beneath a cork floating floor cause the floor to slip?
It is a reasonable concern since a plastic (poly) vapor barrier can be slick. However,
floating floors are designed to move as a complete system. When properly installed on a level subfloor, the interlocking planks function together as one large "floating" unit, preventing individual movement or slippage.
Important Note: This differs from installations using individual planks or tiles that are not interlocked. In a floating floor system, the planks click together to form a single continuous surface. This guidance applies specifically to interlocked floating floor systems and should not be assumed to apply to non-interlocked installations.
Be sure to maintain the recommended expansion gap of 8–10mm around the perimeter so the cork floor can float and expand naturally