Heritage conservation at work

Ontario Heritage Centre façade restoration project

From 2005-2007, the Ontario Heritage Centre underwent a significant façade restoration in three phases. Explore the work of the Trust in giving a facelift to this rare surviving example of a purpose-built Edwardian office building.

The Ontario Heritage Trust — the province's lead heritage agency — has commenced repairs to the south and west stone façades of the Ontario Heritage Centre.

This building — located at 10 Adelaide Street East in downtown Toronto — was originally the headquarters of the Canadian Birkbeck Savings and Investment Company. Built in 1908, the building was designed by noted Toronto architect George Wallace Gouinlock. It is a rare surviving example of an Edwardian office building and, for that reason, is designated a National Historic Site.

The Trust is dedicated to identifying, preserving, protecting and promoting Ontario's rich and varied heritage for the benefit of present and future generations. In 1988, the Trust acquired, restored and adapted the Birkbeck building for use as its headquarters, as a conference facility and to provide office space for non-profit and commercial tenants.

Introduction

The composition of the front façade exhibits the symmetrical grandeur associated with the American Beaux Arts style. The projecting central bay features an unusual and dramatic pair of two-storey arched niches, each containing an aedicule (a temple-like element composed of a pediment supported on columns that stand on a projecting base). The vigorous banding of the façade and carved ornamentation limited to a few select windows is typical of Edwardian baroque style. The stonework also wraps around the southwest corner, enhancing the oblique view of the building from nearby Yonge Street.

The façade is made of both natural stone and artificial cast stone — in this case, a type that was sold under the brand name "Art Stone." In early 20th-century Toronto, artificial cast stone was a popular substitute for more expensive natural stone, particularly when many repetitive units were required. Reusable moulds meant that large quantities of ready-to-install cast stone could be produced more cheaply than natural stone, which had to be quarried and then dressed on the construction site by skilled stone masons.

This cast material was a mixture of cement, filler, pigment and aggregates that could be adjusted to provide a finished surface resembling granite, limestone or sandstone. The surface of the "stone" was often cast or incised after curing, with striations resembling the stone tooling of real stone. Even so, it remained more economical to carve individual one-off ornamental units out of natural stone. As a result, many cast stone façades are a combination of real stone and cast stone.

The Birkbeck Building is no exception. The repetitive "ashlar" blocks that compose the wall areas are all cast Art Stone. The carved sculptural elements — including window wreathes, door and window casings, pediment with tympanum beneath, columns and pedestal bases — are carved from sandstone.

During its almost 100 years of life, the Birkbeck Building has endured the wear and tear of many winters and freeze-thaw cycles, and the resulting water infiltration problems. A number of façade elements were replaced as they crumbled and failed. At some point, the whole façade was painted a light grey colour to hide accumulated dirt and to provide a uniform appearance.

In 2005, the Ontario Heritage Trust started planning a three-phase project to restore the façade in preparation for the building's upcoming centenary.

This restoration project was funded by the Government of Ontario.

Phase 1

Phase 1 involved the careful removal of paint layers from the south façade to reveal and assess the condition of the cast and natural stone in order to determine the most effective restoration approach. Many techniques were tested, including various peel-and-stick paint strippers, JOS low-pressure abrasive cleaning and low-pressure water cleaning. In the summer of 2005, the front façade was fully enclosed in scaffold and the paint layers were stripped, employing techniques suited to the existing material conditions.

Care was taken to remove only the paint layers — not the soot and atmospheric soiling beneath. This revealed a mottled, blackened façade as it would have appeared earlier in the 20th century when Toronto's atmosphere was polluted by coal burning. A close inspection of this soiling revealed a series of slash marks near the entrance doors and along the street level that bear witness to the early 20th-century use of sulphur-tipped matches, struck against the rough surfaces of the building to light cigars before entering the building to conduct business.

The cast stone and natural stone had weathered differently, the former turning a warm brown and the latter a charcoal grey. The condition of the upper two floors was poor. The lower two floors were in better condition. This variety of conditions presented a number of interesting architectural conservation issues. Should replacement units be made of natural or cast stone? To what extent should patina be preserved? Is a unified appearance desirable? The completion of Phase 1 raised as many questions as it answered.

Phase 2

Phase 2 of the project dealt with waterproofing the south foundation wall. In the spring of 2007, the sidewalk in front of the building was removed and the ground excavated down to footing level in order to repair the masonry foundation wall, to add layers of waterproofing and to install a new perimeter drain. This work was made more challenging by the discovery, beneath the sidewalk, of two window wells that originally allowed light into the basement level. They were constructed of brick with an inner lining of white ceramic tiles and were slung from the foundation wall with little support beneath. The waterproofing work was temporarily delayed while these interesting features were documented by a licensed archaeologist. With the "feet" of the building dry and the sidewalk reinstalled, plans were finalized to start actual restoration of the façade in Phase 3 of the project.

Phase 3

Phase 3, started in June 2007, will see the replacement of the cast stone of the upper two storeys of the south and west façades with new cast stone. This step is necessary because years of water damage and a patchwork of unsympathetic repairs render much of the wall unsalvageable. The cast stone and natural stone of the lower two storeys are being largely retained and repaired, in each case with similar materials. The first course of stone at the base of the building will also be replaced with natural stone to return it to its earlier appearance. All of the masonry is being cleaned and treated to return the façade to a unified appearance, while retaining some of the patina of the last 100 years.

The Ontario Heritage Trust is proud to have initiated this project that will ensure the preservation and continued use of this significant National Historic Site.

Menu

Search

Menu

Heritage conservation at work

Ontario Heritage Centre façade restoration project

You may also be interested in