Waterproof coatings are a mixture of rubber and asphalt or all rubber (sometimes called elastometric). These are sprayed onto the foundation, but the material must be heated before application; it is also applied in a thicker coat and is elastic. Waterproof coatings seal the surface from liquid water and from water vapor; they usually are opaque, such as bituminous coatings and some paints. These coatings usually do not cause problems as long as they exclude all water from the masonry.