A building’s silhouette against the sky tells a great deal about the attention its designer paid to its roofscape. The roof of a building is frequently neglected on the grounds that “nobody sees it anyhow.” That may be true when one is near a very tall structure, but as one gradually moves farther away from it to a distant view, the roofscape does reveal itself.
One major difficulty is the mechanical equipment that must be placed on the roof. An even worse problem is the elevator machinery penthouse in buildings that exceed six floors. This issue does not exist in lower buildings, because their hydraulic elevators are low-speed (150 feet per minute). This kind of elevator is actually pushed up by a hydraulic piston and the machinery can be housed in a small room near the elevator on the lowest floor.
Structures seven stories and higher need faster elevators (350 or 500 feet per minute), electrically operated. This machinery is placed on the roof in a penthouse that rises 17-18 feet above the roof. This tall “bump” is very difficult to disguise.
A building’s typical floor plan determines the most economical location for these mechanical necessities, usually right up on the roof. Somewhere on the roof must be a large enclosure to accommodate the kitchen and bathroom exhausts, vents, housing for corridor air-supply fans, chillers and condensing units for air conditioning, as well as the stairs to the roof. Even the boiler is sometimes located on the roof. Moving their locations to aesthetically preferable spots would require expensive horizontal runs often not in the budget. This is an old dilemma for the architect: looks versus cost.
The cheapest solution is to run straight up with ducts or pipes, regardless of the consequences, and we have plenty of examples of this in Evanston. This may be simple carelessness, as at the new Mather Building on the northeast corner of Hinman Avenue and Davis Street, where, just east of the carefully crafted emblematic cupola, a large metal box is plunked down on the roof.
One elegant remedy is to take the exterior skin of the building and carry it up a floor or more, fencing the mechanicals in, and making whatever happens on the roof invisible. This was nicely done on the bank building at the northeast corner of Davis and Orrington.
Another approach to hiding the equipment is seen at the Church Street Station apartment building at the southwest corner of Church and Maple. The roofscape was hidden by making the top-floor units two stories high.
A number of Evanston apartment buildings have cleverly camouflaged roof bumps. The two most attractive solutions are seen on Park Evanston (1630 Chicago Ave.) and on Optima Views (1720 Maple St.).
Rarely is the designer so fortunate that the typical floor plan lends itself to revealing the elevator penthouse as a major feature as was done at Evanston Place on the west side of Chicago Avenue between Church and Clark.
Since most good solutions to the roofscape are too expensive to actualize, designers tend to soothe their consciences by asking, “Who will see it?” As a professor at the UIC School of Architecture, I used to tell my students, “God will.”
To quote Longfellow (1849):
In the elder days of art,
with greatest care
Each minute and unseen part;
For the Gods see everywhere