About Us


ONE Comprehensive Resource
to Execute ONE Vision

Building on a rich history of industrial and commercial success here in New England, we engineered ONE DC to be more than just your standard design-build company. We provide our clients with development expertise in multiple areas and confident execution each step of the way.

See our Building Solutions page to read about the range of services we have available, and our Portfolio for examples of recent work.



Gary Dayharsh, President
Gary Dayharsh brings to ONE DC over 35 years of experience in the construction business, specializing in taking projects from initial concept development through to successful completion. Gary has a degree in civil engineering, having attended the University of New Haven, and diverse experience in commercial, industrial, and community projects of all types and sizes. He has also developed numerous lease-back projects and several business parks, subsequently offering clients shovel-ready land and building packages. Gary has delivered over 1000 design-build projects on-time and within budget, many of these utilizing Butler building systems.
Michael E. Byrnes, Sr. Estimator / Project Manager
Mike Byrnes graduated with a BS in Construction Management from the University of Massachusetts Amherst. He brings to ONE DC over 30 years’ experience and expertise in design-build and commercial/industrial construction with an emphasis on cost control. Mike’s breadth of knowledge allows him to see a project through from conception to design and permitting through to construction. He has been associated with Butler Mfg. buildings his entire career.

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