Florprufe polyolefin vapor barrier glues itself to the underside of a concrete slab — so if it tears, any moisture that gets through won’t migrate. A 1-mil protective coating keeps it from feeling sticky during construction; once the concrete is in place, pressure breaks down the coating and activates the adhesive. At 21 mils, the product is also quite thick. It comes in 4-foot by 115-foot rolls that cost about $700.
Grace Construction Products, 866/333-3726, graceconstruction.com.