The geographic distribution of slate roofing in eastern Canada can only partially be explained by urbanization and accessibility to materials by Toronto roofing companies. Slate roofs in the regions of Trinity Bay, Newfoundland and Eastern Townships, Quebec, certainly fit the classic reason for the use of materials nearness to sources. Yet while most centres in southern Quebec and Ontario were about equidistant from Canadian and American slate quarries, there existed a wide discrepancy in the tendency of each to use slate. The association of slate with particular styles that were unevenly spread across Canada sheds some light on the varied concentration of slate roofing. The large sampling in London, Ontario, for instance, may be attributable to that city’s formative architectural phase occurring at a time when such styles as High Victorian Gothic, Second Empire and Queen Anne Revival encouraged slating. The relationship of style and material was nevertheless far from predictable. Slate roofs were integral in the federal expression of the Second Empire style, but the mansard- roofed cottages dotting the shores of the St. Lawrence River were covered in tin.
As styles diffused, the building practices and labour forces of local areas Quebec may yet prove that the limited use of slate in that province was due to the existence of a skilled force of “ferblantiers” which reinforced the persistence of a building tradition in imported tin long after local slate proved more accessible and less costly.
What class of Canadian buildings had slate roofs? Contrary to the impression suggested by documentary research that governmental, religious and mercantile structures constituted the largest groups with slate roofs, more than two-thirds of the slate-roofs recorded by the Canadian Inventory of Historic Building were residences. Concentrated in Ontario and Quebec, the 2000 dwellings that emerged from the survey emphasize in a dramatic way the popularity of slate in its heyday. Slate-roofed detached residences appear to have been most prevalent, although there were also many slate-roofed town- houses in Montreal and slate-roofed, semi-detached homes in both Montreal and Toronto.