About Us

YA Engineering Services (YAES) is a forensic multi-disciplinary firm that specializes in evaluations of existing structures. Our engineers, architects and non-destructive testing specialists bring decades of experience in conducting forensic investigations. Our President, Richard A. Dethlefs, P.E., S.E., founded YAES in January 2019 after spending over twenty years and becoming a Principal at one of the largest and most well-regarded forensic engineering firms in the United States. Our goal with YAES is to offer a team of highly qualified, technically excellent engineering professionals who work seamlessly together to service the needs of our clients in the model of an engineering cooperative.

Our quality control procedures require that all analyses, reports, and deliverables receive critical technical and style reviews prior to issuance. YAES provides immediate response to new assignments, performs investigations in a timely manner and provides comprehensive reports that are clear, concise, and backed by reasonable analyses and recommendations.


For any questions regarding our policies, procedures, or capabilities, feel free to reach out to Mr. Dethlefs at (206) 890-8511 or our Vice President, Mr. Owen Rosenboom, PhD, PE, SE at (415) 656-9499.

Contact Us

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