In construction, a structure is waterproofed with the use of membranes and coatings to protect its integrity and contents.
Waterproofing is the process of making an object or structure waterproof or water-resistant so that it remains mostly unaffected by water or resisting the ingress of water under certain conditions. Concrete under hydro-static pressure requires additional waterproofing methods to protect it from deterioration.
Concrete is porous, and if not waterproofed, absorbs water, waterborne contaminants and chemicals that cause deterioration. Waterproofing is essential to preserving the structure.