About Us
Our Story
Mainstay Engineering Group, Inc. is a multi-discipline engineering firm providing civil and structural engineering services for highly-technical and complex projects in Science & Technology and other Mission-Critical environments.
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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 throughout the United States in a wide variety of essential services industries including: pharmaceutical, life science/biotechnology, healthcare, industrial & manufacturing, education, data center & semiconductor, sustainable energy, oil & gas and government/military.
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In January 2025, Mainstay proudly welcomed Professional Engineering Associates (PEA) of South Carolina into our organization. This strategic acquisition unites two highly respected engineering firms, combining five decades of expertise in civil and structural engineering. By bringing together exceptional talent and shared values, we offer a broader scope of expertise and an even more robust team and reach dedicated to your project's success.
At Mainstay Engineering Group, we're engineering the future with you, providing the stability and precision that allows your groundbreaking projects to thrive.
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.
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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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Sustainability
We are also committed to responsible sustainability practices and environmental stewardship -- we integrate eco-friendly practices into every aspect of our business and are staffed with LEED Green Associates.
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Our Approach & Core Values
Mainstay's Mission
Empowering progress through exceptional solutions that build for the future and impact lives.
Values
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.
Transparency
Commitment
Responsiveness
Curiosity
Excellence
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.