When protective coatings are properly formulated and applied, they are usually expected to last ten years or more with periodic maintenance. However, occasionally, premature failure occurs, with expensive cost ramifications. The investigation of a field coating failure is considerably different than routine paint analysis, even though the same laboratory equipment is used. Instead, a forensic analysis technique is required, which relies heavily on background information, field sampling and observations, and laboratory testing and analysis.

This paper will describe how one coating consulting company conducts the field and laboratory investigation of coating failures. The structure of failure analysis will be illustrated by three different failures. The first failure involves an alkyd applied over concrete; the second failure involves the delamination of a urethane topcoat from an epoxy primer; and the third failure involves the cohesive failure of an inorganic zinc-rich primer topcoated with a vinyl system.