concrete slab without vapor barrier
A vapor barrier is the key to waterproofing under a concrete basement or slab. Without a vapor barrier, dampness can lead to a damp floor, indoor humidity and mold. Vapor barriers are recommended even in dry climates. Soil always harbors moisture, and the drier air will pull out the moisture.ow to Install a Vapor Barrier. Add a strong, impermeable vapor barrier under the concrete. It can be installed over or under the gravel base under a basement. For a foundation on slab, install the vapor barrier under the gravel base.