Finish TradesQuestion 478 of 700
Before installing engineered wood flooring over a concrete slab-on-grade, a 6-mil polyethylene (or equivalent) vapor retarder is commonly placed MAINLY to do what?
a.Slow moisture vapor rising from the slab so it does not damage the flooring
b.Add structural stiffness to the slab
c.Serve as the finished wear surface
d.Provide the required fire rating
Explanation
Concrete slabs continually emit moisture vapor that can cup or delaminate wood flooring, so a vapor retarder slows that migration. It adds no structural stiffness, is not a wear surface, and does not provide a fire rating.
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