Trees of knowledge

Architectural Review, The, Jan, 1997 by Raymond Mendez

The recently completed addition effectively doubles the size of the library. It is meshed into the old building by means of an arcaded street, that extends out into the parking lot, providing both shelter and a civic focus for visitors. The street is the principal orientation device, leading into a double-height entrance space. From here you either turn left into the new community hall, or right into the library. The entrance space is intersected by a secondary axis, directly in front of the reception desk. This leads into the heart of the library and its various lending departments - adult, reference, children and so on. The crisply angular forms of the new extensions are executed in brindled brick, with orthogonal openings punched into the skin.

But the main surprise among this workmanlike, contextual building is the new entrance space. This is a generous volume glazed at both ends, which acts both as general reception area and break out space for the community hall. A two-storey existing wall dictated the overall scale and configuration, but what could have been an unremarkable lobby has been magically transformed into a space of great presence and delight. Closely spaced timber columns support a network of trusses that radiate out like branches from their tops. The trusses in turn support a monopitch roof. The elongated proportions of the columns and trusses have a sensual delicacy, like long thin fingers, that recalls the organic complexity of fellow Midwesterner Fay Jones. More obviously, as a response to the library's sylvan setting, the structure resembles a forest of well regimented trees.

The challenge for both the architect and engineer was to minimise the size of the timber members, so as to create as light a structure as possible. The outcome is a series of members ranging in size from 3in x 6in for the trusses, to 3in x 12in for the columns. (Local building codes stipulate a minimum dimension of 3in.) The truss pattern is repeated on each of the columns, but the trusses are positioned in such a way so that each column trunk appears different. Yet despite the evident functional and visual integrity of the design, timber framing is rare in this part of the USA. The Chicago building code does not generally permit timber structures, because of concerns about fire performance.

The engagingly tectonic quality of the structure serves to constantly animate the space. Light filters in from the glazed ends together with clerestories at upper level, producing a seductive play of shifting shadows. A clerestory strip cut into the wall of the meeting hall gives tantalising glimpses of the structural tree tops. At night, the illuminated structure glows enticingly, a grove of radiant, rustic manmade trees creating a beacon in the suburban landscape.