Serving the Puget Sound since 1984, Mayes Testing Engineers has offices in Lynnwood and Tacoma with a combined staff of over 150 employees. As part of Terracon, our local team is supported nationally with more than 5,000 employees in over 150 offices. Quality service and client satisfaction have helped Mayes Terracon become one of the largest and best-known providers of construction quality assurance services in the Pacific Northwest. With the largest staff of certified inspectors in Washington state, our firm has worked on many high profile, complex construction projects. Our clients include Microsoft, Boeing, University of Washington, Amazon, Providence Health System, Port of Seattle, and many private and public agencies.