The peel-n-seal product, among many other similar products are used effectively on the floorboards, without problems. Prior to installing, all seams should be sealed properly with a good, quality seam sealer/seam caulk, as done at the factory.
Moisture enters from the outside, through improperly sealed seams or openings in the floor boards, kick panels, rockers, cab corners, etc. If the cab is watertight, including the doors, glass and windshield, water will not enter the cab of the vehicle, therefore, not reside/seep under the carpet, padding or self-adhesive matting.
If this product is installed properly and all seams bridged with foil tape, water will not permeate under it. As a good maintenance program, the carpet should be pulled back routinely, to ensure there is no moisture wicking into the cab, via breaches in the floor boards, kick panels, rockers, doors, windows or cab corners, as well as, being good housekeeping.
