In praise of older windows

Casement windows of the Oval Boardroom

Buildings and architecture

Published Date: Nov 15, 2007

Photo: Casement windows of the Oval Boardroom

Façade: a word of double-edged meaning. Architecturally, it refers to the face of a building. In literature, more often than not, it connotes a front of showy misrepresentation intended to conceal something unpleasant.

The Ontario Heritage Trust is in the midst of restoring a façade – that of its Toronto headquarters, the Ontario Heritage Centre. This façade has a restrained Edwardian character punctuated by bursts of Beaux Arts-spirited ornamental swags, wreaths and figural carving. It is made of industrially produced cast stone but has hand-carved sandstone embellishments. Portions of the cast stone have deteriorated beyond the reach of conservation and are being replaced with new like material. The rest is being repaired and cleaned. But how much to clean? What constitutes patina and should it be retained? How uniform must old and new look? The Trust is taking a cautious approach to gently preserve the face of this building so that it comfortably takes its place on Adelaide Street, as one of a few older citizens in a neighbourhood increasingly populated by new arrivals.

The Ontario Heritage Centre was designed by architect George Gouinlock, built in 1908 for the Birkbeck Saving and Investments Company. The façade was the dignified face of company headquarters – a best foot forward to what was essentially a speculative office building of typical quality. This face stylishly represents the building behind it, but also reveals something about the way the building was intended to function.

Interior corridor with frosted glass partitions

Windows are where style and function come together. The façade contains a great variety of windows – circular and large arched windows with glazing subdivided by elegantly thin mullions, operable single-hung sash windows and two giant semi-circular windows at the second floor, each swinging open on its central pivot. The windows of the other sides of the building are all operable as well. If we look at the façade, and then through its windows into the building, an intrinsic characteristic is revealed: this building was designed to function with natural light and natural ventilation. The modern mechanical systems installed in 1989 were designed to complement the function of these earlier ventilation devices.

Elevators were commonplace in 1908. Electricity was available but privately controlled and unreliable. Ceiling fans provided limited mechanical ventilation. Air conditioning would only become available in 1915 and the chiller that provided cooling for large occupied spaces was not introduced until the mid-1920s.

Between about 1880 and 1915, multi-storey commercial buildings made possible by elevators still relied primarily on natural ventilation and light. Buildings were designed to respond to climate and site in a way that made them work with the elements rather than against them – a common-sense and unselfconsciously green approach to environmental control.

The Birkbeck Building has graduated ceiling heights. The ground floor, where the light condition is least adequate, has 20-foot ceilings with very tall windows and a mezzanine to maximize day-lit office space. The second floor is 13 feet high, to accommodate large windows in rooms associated with prime, walk-up tenant space. The typical upper floors have 11-foot ceilings, sufficient to light small repetitive offices while reducing the stairs to be climbed.

Transom panel that promotes air circulation

Transom panel that promotes air circulation

In plan, the Birkbeck Building is open on three sides. Ancillary spaces – such as stairs, washrooms and vaults – are relegated to the darkest portion of the floor plate against a blank party wall. The average depth of an office is about 24 feet, which is the depth that daylight will penetrate. There is a slightly indented light court facing west to catch light when it is most valuable and difficult to obtain – the late afternoon. Sash windows admit light into the perimeter office spaces and the general office area beyond. These private office areas are separated from the public corridor by wood partitions with large frosted glass panels that still allow light to filter through to the internal corridor.

A similar set of passive devices regulates ventilation. The corridor has operable windows at either end to provide cross-ventilation – creating, in effect, a large central cooling duct. Internal doors incorporate a variety of transom panels, each with their own system of manual controls that, like baffles, can be adjusted to control and channel cross-circulation of air. They come in a variety of sizes and are devices that are full of utility, but also of delight.

The façade of the Birkbeck Building conceals something that is practical, but by no means unpleasant – a building that takes full advantage of natural light and ventilation. At a time when new buildings are being designed with an eye to sustainable levels of energy consumption, the Birkbeck Building – and others like it – provide enlightened examples of how it can be done.