A waterproofing membrane is a layer of water-tight material that is laid onto a surface to prevent water leaks or damage. Waterproofing membranes generally consist of liquid applied or pre-formed sheets. They can be adhered to or installed around the foundations (like a structural slab) to prevent water penetration. When should you use membrane waterproofing? Waterproofing membranes are used for many applications, such as covering concrete while it is being formed to prevent water from compromising the structural integrity of the concrete, or coated on products that are submerged under water where corrosion is a concern.