Howard Hughes Medical Institute Expansion

Bethesda, Maryland
Howard Hughes Medical Institute
Bowie-Gridley Architects
150,000 Square Feet
Year Completed: 

The Howard Hughes Medical Institute (HHMI) Expansion project consists of a 150,000 square-foot addition to the existing structure, which was originally constructed by Clark in 1993. The addition is located on an area of the site where most of the public utilities previously entered the existing building. Clark was contracted to perform a six-month utility relocation phase in order to accommodate the new construction.

The HHMI Expansion includes 64,000 square feet of above-grade office space and 86,000 square feet of below-grade parking. The structure is concrete for the two below-grade levels and structural steel for the two levels above grade. The skin is brick with limestone paneling and granite dispersed throughout. Inside, high-end finishes include custom-made casement wood windows, natural finish sycamore veneered wall and ceiling panels and casework, natural finish maple solid stock millwork, stone flooring, interior glazing, and several skylights. The site contains several new stone retaining walls, extensive landscaping, three new courtyards, as well as two large water features.

The mechanical scope of work included the phase out and removal of the existing facility’s chiller plant and installation of a new air temperature control system, which supports both the existing facility and new expansion. All of this work was conducted while the existing facility remained fully-occupied and operational. Clark managed the meticulous planning and coordination required to create a seamless transition between the plants.


The project achieved LEED Gold certification. The lighting system at HHMI is comprised of a complex custom fixture package and an intricate lighting control package. This complete system maximizes energy savings and still matches the ornate wood, stone, and brick aesthetic finishes in the new facility. Additionally, the Clark team was able to recycle roughly 95 percent of the construction waste on the project. 

ABC Excellence in Construction Award - Drywall
Excellence in Construction Award - Masonry
WBC Craftsmanship Award - Interior Stone & Marble
WBC Craftsmanship Award - Masonry - Exterior Stone
WBC Craftsmanship Award - Masonry - Unit Masonry
WBC Craftsmanship Award - Mechanical/HVAC Piping
WBC Craftsmanship Award - Plaster
WBC Craftsmanship Award - Woods & Plastics/Architectural Millwork

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