Frequently Asked Questions
Do I need a moisture barrier under vinyl plank or laminate?
Over any concrete slab, yes — slabs push water vapor up indefinitely, and floating floors trap it. A 6-mil barrier film breaks the path. Over wood subfloors, skip the film so the wood can breathe.
How do I install moisture barrier film?
Roll it out across the slab, overlap seams 8 inches and tape them, and run it slightly up the wall behind the baseboard. Lay the flooring's underlayment or pad on top.
How do I know if my slab has a moisture problem?
Tape a 2-foot square of plastic to the slab for 24–72 hours — condensation or darkening underneath means active vapor drive. For flooring warranties, a calcium chloride or RH probe test gives the numbers.