Canadian Property Management | January 12, 2024
Glade Schoenfeld, BASc, P.Eng., RRO, CAHP | Principal

Preserving the past, one historic roofline at a time

From slate to clay, concrete to sheet metals, and cedar to asphalt, roofing materials today are selected for a variety of reasons, including durability, cost, embodied energy, ease of maintenance and constructability. Historically, however, architectural style and character bore more weight when determining materials and heavily influenced the design process.

“Roofs on historic buildings were intrinsic to the original architecture—including massing, texture and colour,” explains Glade Schoenfeld, Principal at RJC Engineers. “The form of the roof needed to be both functional and aesthetic, but often the aesthetic aspect of the design made the roofs difficult to access, which necessitated the use of highly durable materials.”

Popular, durable roofing materials included copper, zinc, and raw slate. Though costlier to source and install than other options, these materials were known to last 100 years in excellent condition while contributing significantly to the architectural expression of the building. Today they are found in the rooflines, domes, parapets, balustrades, gables, and other ornamentations of historic buildings, and much of Schoenfeld’s work involves conserving these treasures to be functional yet still enjoyed and appreciated for generations to come.

“Heritage roofs are like any other Character Defining Element (CDE) on a historic building,” he says. “When the roofing is identified as a CDE, the preferred approach is to conserve, preserve or restore depending on the material and the condition of the roof. While copper and zinc can be restored because the tools, materials and trade knowledge remain available, slate is a little different. It is such a durable material that it can be reused, so preservation is the preferred approach.”

Each material also responds differently to environmental influences, and as such, some heritage roofs age differently than others. For instance, as copper ages, it forms a patina that protects it and adds to the overall aesthetic. Depending on the environmental conditions the roof is exposed to, the patina can range in colour from copper-green to copper-bronze.

Read Publication Back to Published Items