Air leakage, water penetration, and structural performance testing on pre-construction mock-ups can validate design, workmanship, and material selection and provide insight into how the building envelope will perform once installed and exposed to extreme weather conditions. Mock-up testing allows for the discovery of potential problems with compatibility of exterior building components or installation issues and possible resolutions before a construction project even begins. Walt Cichonski, of LF Driscoll, provides his take on the importance and benefits of mock-up testing along with his experience working with Intertek. "The things that you learn before we actually apply those in construction, are completely invaluable."