Howard Hughes Medical Institute: Janelia Farm Research Campus

Ashburn, VA

Close Up

  • Architect

    Rafael Viñoly Architects

  • Engineer

    Thornton Tomasetti

  • Façade Consultant

    Building Enclosure Analysis

  • GC

    Turner Construction Company

  • Completion


  • Building Type


  • LEED Rating

    Silver certified

  • Program

    3 stories, 760,000 sqft

  • Façade Area

    Design/assist-design/build program for 147,000 sqft of structural glass that represents one of the largest and most diverse installations of its type in the United States

  • Glass

    16 different glass panel types with little dimensional repetition and a design that required the pinnacle of glass production capabilities at the time of completion





Cladding high-rise towers using advanced exterior wall technology is a specialty of Enclos. Building enclosures come in wide variations of design and performance criteria, and Enclos particularly excels at the custom, highly complex structural glass enclosures that push the boundary of design, material and installation. Rafael Viñoly Architects' design for the Janelia Farm campus provided a milestone for load-bearing structural glass design with 147,000 square feet of structural glass facades (SGF), making it one of the largest installations of its type in the world.

The research facility is a 900 foot long, three-story, serpentine building set into a hillside along the Potomac River in Northern Virginia. The enclosure consists predominately of custom structural glass constructs. The interior of the building also features large expanses of structural glass wall systems. Low-rise private residences compliment the custom glass designs of the project. The facility’s massiveness is masked by the property’s wooded tree lines and the second largest green roof in the world, but if stood upright the central facility would equal the equivalent of an 85-story building. Two arch-like glass enclosures supported by a minimalist stainless steel framing system connect the top two floors of the campus, accenting the facility’s flowing curves and surrounding topography while continuing the theme of expansive glass corridors. Throughout the first floor, trellis beams extend to support the exterior glass wall and roofing system, enclosing the corridors and providing housing for HVAC, sprinkler and lighting systems.

Enclos acted as the design/builder of the various unique glass systems, working closely with the architect to realize the vision of maximized transparency in the building enclosure. This was accomplished by developing seven unique glass system types in response to differing functional requirements, including using glass as a structural element in support of glass cladding. Considerations of redundancy were a primary design driver for systems such as the glass corridors that resemble a “house of cards” made entirely of glass. These systems were validated by one year of independent testing.

Janelia Farm includes 16 different glass panel types with little dimensional repetition, and a design that required the pinnacle of glass production capabilities at the time of its completion. Panels spanned up to 13 x 10.5 feet. Glass entrances, corridors and interior wall partitions were created using monolithic ultra-clear, low-iron glass. The corridor glass consists of dual interlayer, 3-ply laminated glass lites of 3/8 inch Diamant with .060 clear PVB interlayers. The large 3-ply panel sizes of approximately 140 square feet resulted in individual fabricated panel weights approaching 1,800 pounds. The project includes 60 custom dies for aluminum extrusions systems, included doors, rainscreen roof panels and operable vents.

Site logistics and scheduling issues were particularly challenging on this project, and represented a leading reason Enclos was selected as the glazing design/builder. As typical of the Enclos project development process, a safe and efficient installation method was developed in parallel with a fail-safe design. Facade installation time is estimated at 85,000 man-hours.