A clerestory window is a large window or series of small windows along the top of a structure's wall, usually at or near the roof line. Clerestory windows are a type of "fenestration" or glass window placement found in both residential and commercial construction. A clerestory wall often rises above adjoining roofs. In a large building, like a gymnasium or train station, the windows will be positioned to allow light to illuminate a large interior space. A smaller home may have a band of narrow windows along the very top of a wall.
Originally, the word clerestory (pronounced CLEAR-story) referred to the upper level of a church or cathedral. The Middle English word clerestorie means "clear story," which describes how an entire story of height was "cleared" to bring natural light to sizable interiors.
Designing With Clerestory Windows
Designers who wish to maintain wall space and interior privacy AND keep a room well-lighted often use this type of window arrangement for both residential and commercial projects. It is one way to use architectural design to help your home out of the darkness. Clerestory windows are most often used to naturally illuminate (and often ventilate) large spaces such as sports arenas, transportation terminals, and gymnasiums. As modern sports stadiums and arenas became enclosed, with and without retractable roofing systems, the "clerestory lens," as it's called on the 2009 Cowboys Stadium, became more common.
Early Christian Byzantine architecture featured this type of fenestration to shed overhead light into the massive spaces builders were beginning to construct. Romanesque- era designs expanded the technique as medieval basilicas achieved more grandeur from height. The architects of Gothic-era cathedrals made clerestories an art form.
Some say it was American architect Frank Lloyd Wright (1867-1959) who adapted that Gothic art form to residential architecture. Wright was an early promoter of natural light and ventilation, no doubt in response to working in the Chicago area during the height of America's industrialization. By 1893 Wright had his prototype for the Prairie Style in the Winslow House, showing second-story windows under the enormous eave overhang. By 1908 Wright was still struggling with a perfectly beautiful design when he wrote: "… often I used to gloat over the beautiful buildings I could build if only it were unnecessary to cut holes in them… " The holes, of course, are the windows and doors. By the time Wright was marketing his Usonian homes, the clerestory windows had become an important part of both the interior design, as seen in the 1939 Rosenbaum house in Alabama, and the exterior design, as in the 1950 Zimmerman House in New Hampshire.
"The best way to light a house is God's way - the natural way… " Wright wrote in "The Natural House", a 1954 classic book on American architecture. The best natural way, according to Wright, is to place the clerestory along the southern exposure of the structure. The clerestory window "serves as a lantern" to the house.
More Definitions of Clerestory or Clearstory
"1. An upper zone of wall pierced with windows that admit light to the center of a lofty room. 2. A window so placed." - Dictionary of Architecture and Construction
"The topmost windows of a church nave, those above the aisle roof, thus any high band of windows" - G. E. Kidder Smith, FAIA
"A series of windows placed high on a wall. Evolved from the Gothic churches where the clerestory appeared above the aisle roofs." - John Milnes Baker, AIA
Architectural Examples of Clerestory Windows
Clerestory windows illuminate many of Frank Lloyd Wright-designed interior spaces, especially the Usonian home designs, including the Zimmerman House and the Toufic Kalil Home. In addition to adding clerestory windows to residential structures, Wright also used rows of glass in more traditional settings, such as his Unity Temple, Annunciation Greek Orthodox, and the original library, the Buckner Building, on the campus of Florida Southern College in Lakeland. For Wright, the clerestory window was a design choice that satisfied his aesthetic and philosophic ideals.
Clerestory windows have become a mainstay of modern residential architecture. From the 1922 Schindler Chace house designed by the Austrian-born R. M. Schindler to the student designs of the Solar Decathlon competition, this type of fenestration is a popular and practical choice.
Remember that this "new" way of design is centuries old. Look up at the great sacred places across the world. Heavenly light becomes part of the prayerful experience in synagogues, cathedrals, and mosques throughout the ages, from Byzantine to Gothic to Modern structures like architect Alvar Alto's 1978 Church of the Assumption of Mary in Riola di Vergato, Italy.
As the world became industrialized, natural light from clerestory windows supplemented the gas and electric lighting of venues such as Grand Central Terminal in New York City. For a more modern transportation hub in Lower Manhattan, Spanish architect Santiago Calatrava returned to ancient architectural history, incorporating a modern oculus - a version of Rome's Pantheon extreme clerestory - showing again that what's old is always new.
A Selection of Clerestory Window Examples
- Frank Lloyd Wright On Architecture: Selected Writings (1894-1940), Frederick Gutheim, ed., Grosset's Universal Library, 1941, p. 38
- Dictionary of Architecture and Construction, Cyril M. Harris, ed., McGraw- Hill, 1975, p. 108
- G. E. Kidder Smith, FAIA, Sourcebook of American Architecture, Princeton Architectural Press, 1996, p. 644.
- John Milnes Baker, AIA, American House Styles: A Concise Guide, Norton, 1994, p. 169
- Additional photo credits: Cowboy Stadium, Ronald Martinez/Getty Images (cropped); Winslow House, Raymond Boyd/ Getty Images (cropped); Alto Church, De Agostini/Getty Images (cropped); Zimmerman House, Jackie Craven