A waterproofing system is an impenetrable membrane connected to a drainage system that contains moisture within a wet area so that it does not cause damage to adjacent structural elements or unhealthy living conditions.

The term waterproof describes something that is unaffected by water or covered with a material that does not allow water in. Such items are suitable for use in wet environments (outdoors) or under water. Waterproofing is the treatment of a surface to prevent the passage of water under hydrostatic pressure, or the process where a building component is made totally resistant to the passage of water and/or water vapour.