Coatings used on structure foundations can generally be categorized two ways, dampproof and waterproof. Damproofing is defined in Means Illustrated Construction Dictionary, 3rd Edition as a water-resisting treatment or material applied to the surface of a concrete or masonry wall to prevent passage or absorption of water or moisture. Waterproofing, on the other hand, is defined as any number of materials applied to various surfaces, e.g., a building foundation, to prevent the infiltration of water.

According to Means Building Construction Cost Data 2009>, there are several materials used in the construction industry today for damproofing. Bituminous asphalt coatings are obtained from the coal or petroleum distillation process. They can be applied to vertical and horizontal surfaces by means of brushing, troweling and spraying and can contain non-asbestos fibers that act as a reinforcing component. Cementitious pargetting is a thin layer of cement applied to a surface by means of a trowel or it can also be sprayed on and troweled to uniformity. Admixtures can be incorporated into the cementitious mix to increase its functionality. Silicone based liquids that are sprayed or brushed onto masonry or concrete surfaces can also be used for damproofing.

Again, according to RSMeans Building Construction Cost Data 2009 there are several methods used for waterproofing in the construction industry. Bituminous membrane waterproofing uses several overlapping layers of bitumen and bitumen saturated felt that are installed vertically and horizontally on concrete or masonry surfaces. Special equipment is needed to heat the bitumen so it will be easier to spread. Elastomeric sheet waterproofing uses any one of a number rubber or plastic sheets. The sheets can be joined together with solvent, tape strips and adhesives and are held in place by materials much like contact cement. Bentonite is a clay based waterproofing that comes in panel or granular form. Moisture in the ground will cause the bentonite to swell completely seal the structure to which it is applied. Another waterproofing method uses a cementitous based slurry that includes iron particles that is troweled in place.

Installed costs will range from under $1.00 per square foot to over $6.00 depending on method, thickness, number of coats and specific local conditions.

Architects and engineers who are designing structures that have some portion below grade, or need some form of waterproofing, should be familiar with all methods and their potential costs.