Larson Design Group Announces Addition of Oklahoma City Engineering Firm ZRHD to Strengthen Federal Market Offerings

Larson Design Group (LDG), a leading national architecture, engineering and professional consulting firm, announced that ZRHD – an engineering consulting firm in Oklahoma City with high-end expertise in the design of mechanical and electrical systems for federal, commercial, institutional, and industrial clients nationwide – will join the company. The merger will be effective January 1, 2023, and brings a team with a strong history in building systems engineering to LDG. With over 1,000 assignments in the United States and abroad, ZRHD has a strong resume in the federal, education and commercial markets by designing a variety of project types including office buildings, hangars, laboratories, and training and research facilities and building expertise in energy performance projects. This merger follows the company’s January 2022 acquisition of Oklahoma-based firm LWPB, an architecture and interior design company based in Oklahoma that also possesses robust experience in the federal, education, and commercial markets.

“Our strategic partnership with ZRHD strengthens Larson Design Group by continuing to grow our building engineering expertise in our current markets and complements our federal team as we continue to expand nationally to multiple agencies,” said David Martin, PE, President and CEO of LDG. “We welcome ZRHD to our growing team and look forward to working together for the success of our clients.”

Originally known as Zumwalt-Ragsdale, Inc. in 1986, and then merging with another respected Oklahoma City company, Herring and Danner, Inc., in 1992, ZRHD has grown to be an industry leader known for solving difficult design issues associated with retrofit and renovation projects with an emphasis on building energy performance.

“We’re proud of the strong reputation our ZRHD team has built together with so many meaningful institutions over our 36 years in business to produce best in class engineering projects,” said Randall Carter, President of ZRHD. “We’re thrilled to be joining Larson Design Group, as it’s a company that recognizes our team’s value and how we can make a great impact to further grow its business in the federal space.”

For more information about Larson Design Group, visit and follow /LarsonDesignGroup on Facebook, @LDGnews on Twitter, Larson-Design-Group on LinkedIn and @LarsonDesignGroup on Instagram. About Larson Design Group Founded in 1986, LDG is an award-winning, 100 percent employee-owned national architecture, engineering, and consulting firm with 18 offices in seven states and a vision to elevate client relationships, enrich the careers and lives of its employee-owners, and enhance the communities in which it operates. Click here to view open career opportunities at LDG.