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About Us

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Our Story

Nationally recognized as a leader in civil & structural engineering solutions for over 20 years, Mainstay Engineering Group, Inc. has been at the forefront of providing engineering solutions to life sciences and high-tech, mission critical companies, completing over 4,000 successful projects since its founding in 2002. Our design professionals are licensed to perform engineering services in the United States, but our reach extends beyond borders, having performed consulting services internationally.


Mainstay began with a focus on servicing Life Sciences. Over the years, we have grown to a team of licensed experienced professionals and Subject Matter Experts (SMEs) servicing partners and clients in a wide variety of essential services industries. Today, 85% of our portfolio comprises Mission Critical projects, a testament to the trust our clients place in us for their most important projects.


The Mainstay Difference

Our team's relentless pursuit of excellence is fueled by a unique, multi-disciplined approach to anticipate our clients' needs and provide creative and flexible facility design solutions that optimize every project. 

Health & Safety

Mainstay upholds the highest safety standards, especially when working with mission critical, life sciences and pharmaceutical clients. We are regularly recognized for our numerous safety awards, and most recently earned the prestigious 2023 Highwire Gold Award for Safety. This achievement reflects the unwavering commitment and dedication of every individual at Mainstay to creating a workplace that prioritizes safety above all.

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Our Approach & Core Values

Mainstay's Mission

Empowering progress through exceptional solutions that build for the future and impact lives.


Our core values form the bedrock of Mainstay’s culture, guiding us in every aspect of our work. And, our commitment to diversity, equity and inclusion is core to who we are as a company and enables us to better serve our clients and partners. We recognize the value of fostering an inclusive and equitable work environment – one that fosters diversity of opinion, innovation, and creates a workplace that reflects the communities we serve. 

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Our History

Mainstay's journey began in 2002 with a singular mission; to redefine the landscape of civil and structural engineering services. Founded by Matthew E. Hilbush, P.E., Mainstay Engineering started with a niche identity in the pharmaceutical sector. This laid the foundation for a remarkable journey to becoming one of the leading engineering firms in the country. 



1750 Walton Road, Suite 200

Blue Bell, PA 19422


50 South 16th Street, Suite 1700

Philadelphia, PA 19102


9121 Anson Way, Suite 200

Raleigh, NC 27615

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