Occupied in 2002, the Johnson corporate headquarters houses 500 employees in a 180,000 sf building including three office floors above ground floor retail and restaurant facilities. It is located on a full downtown block surrounded by low-rise structures and features narrow floor plates organized in a C-shape around a courtyard facing Lake Michigan. The building is registered for LEED (Leadership in Energy and Environmental Design) certification.  From the beginning, the client stressed the importance of incorporating sustainable strategies into the building design. Loisos+Ubbelohde assisted the design team in developing a high-performing daylighted building.

The office floors have substantial glazing in all directions and the building interior is more exposed to exterior conditions than a typical office with a deep floor plate and reflective skin. These characteristics require a building envelope that controls solar heat gain, direct beam sun penetration and excessive glare, using both exterior and interior shading devices and high performance glass. Advance glazing is designed to work with daylighting and shading strategies, as selective coatings maximize visible transmission of daylight while controlling solar gain and keeping the view to the outside clear.

We identified shading strategies using sun penetration studies developed in Radiance simulations. Exterior shading of the view glass is provided by overhangs mounted at the bottom of the clerestory on east, south and west orientations, with the upper light glazing set deep in the wall for exterior shade. DIffusing roller shades, automatically controlled in open office areas and manually controlled by occupants in private offices, are installed as a secondary system to shade both clerestory and view glass when the exterior overhangs cannot completely shade the glass. Using DOE-2.1e parametrics, we also analyzed energy savings implications of light-dimming controls and the depth of exterior overhangs.