Photo courtesy ARCOP/Fournier Gersovitz Moss Architects in JV
Natural stone: Past and future
If the ambitious remediation of the Parliament Buildings proceeds as planned, when members of Parliament (MPs) begin thumping their desks during opening session next year, the interior appearance of the House of Commons will be quite different than it was 150 years ago.
The sound will reverberate off the best of the faithfully restored original West Block façade and the state-of-the-art, newly built freestanding steel-and-glass pavilion, supporting a high-tech glazed roof covering the space (once the outdoor courtyard of the West Block).
Occupants will have the opportunity to observe the prodigious results of efforts to rehabilitate the West Block heritage façade up close while the Centre Block is rehabilitated over the next five to seven years. The new—albeit temporary—House of Commons, with its traditional viewers’ gallery, will serve as a transitory home for the elected assembly, media representatives, and numerous public visitors, as will three underground levels of a new visitors’ centre.
Even knowledgeable construction professionals will likely need a guidebook to fully appreciate the significance of the carefully restored natural stone façade, visible at eye level from the viewers’ gallery, and the sophistication of the new triple-glazed, energy-efficient glass and steel components overhead—utilizing, for the most part, high-quality Canadian materials, as the original buildings did.
The design professionals and specification writers working on the original Parliament Buildings devoted considerable attention to site selection and choice of materials, particularly the natural stone and the fenestration elements utilized for the building envelope. This is unsurprising, considering the great amount of space within which these professionals had to work. They anticipated using a great deal of dimensioned stone, envisioning a façade comprising approximately 50,000 masonry units, as well as more than 500 windows and doors/entrance assemblies.
Photo courtesy RJW-Gem Campbell Stonemasons Inc.
Microfilm reports stored at the Archives and Library of Canada reveal the buildings came very close to being fabricated with the same bland, grey limestone used for the canal. However, the site selection committee noticed some Nepean sandstone lying about Barracks Hill, and requested an evaluation of this new material. After a technical review and calculation of what costs, if any, would be involved in building with this attractive stone, they chose to use it, making it an important element of these structures’ distinctive appearance.
In spite of the slight increase this choice caused in raw material and transportation costs, the readily available sandstone was the committee’s first choice. The stone was tested and evaluated by government geologists, who—along with the project’s design professionals—determined its transportation costs, colour, texture, and durability would be appropriate for the buildings.
This cream-coloured sandstone of the Potsdam formation was obtained from Nepean, approximately 16 km (10 mi) from Ottawa, and finished onsite in a stone-processing facility. Although samples of the stone in its natural formation can still be seen near present-day Kanata, the quarry itself closed in the 1960s. At the height of the Parliament Buildings’ construction (following the fire of 1916 in the Centre Block on Parliament Hill), the demand for stone was such that a total of seven quarries were required to supply sufficient tonnage.
When the buildings were constructed, using local stone for prominent government and religious buildings was common practice, because it promoted environmentally sustainable construction and also ensured the structures remained locally distinctive. For example, the Alberta and British Columbia Legislative Buildings both used Vancouver Island granite. Similarly, the Manitoba and Saskatchewan Legislative Buildings were constructed with Tyndall stone quarried at nearby Garson, Man. The Ontario Legislative Building complex was fabricated in 1886 using pink sandstone quarried from Orangeville, Ont., and the Nova Scotia, Prince Edward Island, and New Brunswick Legislative Buildings also employed natural stone from nearby quarries.
The use of readily available local stone has numerous benefits; in addition to legislative structures, the material has been employed for many prominent commercial and institutional buildings in the past. As well as providing localized continuity and economic benefits for surrounding communities, locally available natural stone provides cost and logistic benefits for large-scale construction projects. Its durability, appearance, and versatility often makes it the material of choice, as was the case with the Parliament Buildings—even for the slate roof.
