DELTA®-FL is a dimpled, heavy-duty, gray plastic membrane for concrete and slab-on-grade floors that helps to keep moisture out of your basement. The membrane provides a significantly more comfortable floor. DELTA®-FL protects sensitive materials by providing a reliable capillary break and vapor barrier. In a conventional basement, dry air in the living space acts as a “magnet” for water vapor migrating up through the concrete. The air gap created by DELTA®-FL allows the water vapor pressure above and below the concrete slab to equalize, while preventing the moisture from migrating further inwards. Hence, moisture does not affect the flooring material and your basement area stays dry and comfortable. The membrane also provides a thermal break, which increases the comfort in your basement and makes the floor feel warmer.