Antimicrobial coatings to protect surfaces and a method of applying such a coating are disclosed. An antimicrobial coating may be applied to a surface, such as the interior surface of a building's exterior wall. The interior surface must be accessed, and then an antimicrobial coating is provided and applied. The antimicrobial coating includes an inorganic antimicrobial additive and a colloidal polymeric medium. The inorganic antimicrobial additive may be silver, platinum, gold, palladium, copper, zinc, boron, or a compound of any of those elements. By including an ultraviolet tracer or color dye additive in the coating, it is possible to detect the coating at any time, provided that the surface is accessed.