Roofing

A roof is the “Architectural Persona” of a house

Homeowners should conduct a careful inspection of the attic’s roof framing to identify any evidence of water infiltration or decay, or any piece of the framing that may be missing or that shows signs of rotting. Ideally, such an inspection should be conducted every fall to detect any potential problem.

Roofs dominate the physical environment of a built area or of a street. They are like aerial sculptures that emphasize the visual importance of a building, determine its volume and stress its particular style and character. Beyond its function of covering a building and protecting it against weathering, a roof also bears witness to a builder’s aesthetic concerns. Each cultural period had its favourite styles, design details that translate into know-how and ways of combining the materials of a building’s different components including its roof.

Shingled RoofingAn aerial sculpture

As an aerial sculpture, a roof is characterized by its shape, its mass, its colour, the quality of its materials and their combination, the various angles in its volume, i.e. those elements that give it its particular character – its rough edges, irregularities, all visual features that break the monotony of a structure. The builder’s personal taste or the passing trends of a given era are not the only criteria that dictate the choice of a particular type of roof. The shape chosen also takes into account the region’s climate, building traditions, available materials, the building’s intended use, and interior layout. Among those, climatic conditions have had a particular influence on decisions with respect to a roof’s pitch, as well as on the choice of certain materials over others in order to prevent snow and ice buildup on the roof edges.

The availability of materials is also a determining factor. For example, slate, widely used in Europe, was quickly replaced in this country by wood shingles – because fasteners did not resist well to our harsh climate, and because getting sufficient supplies was difficult, given that slate was imported from Europe. It was only after trade expanded and local quarries were opened in the 19th century (Victorian era) that slate was once again used as a roofing material. Climatic conditions also explain the particular shape that would gradually be adopted for the eaves to allow for proper water drainage.

Shapes of roofs on houses

Type of roofing

The double-slope roof – In Québec, the oldest roofs are those with a double-slope, also called gableUpper part of the wall that supports the roof structure of a building. The triangular upper part of the wall of a building that creates a duo-pitched roof. roof or double-eave roof. The pitch of the roof was determined by local climatic conditions, i.e. the harsh, extended winter, with its risks of snow and ice buildup. Snow and ice discharge from the roof was made easier by a more pronounced pitch.

The hip roof – This type of roof calls for more complex framing since it has four sloping sides that meet in four hips, two longer ones over the front and back façades and two smaller ones at each end of the building. Many houses on île d’Orléans were built with this type of roof.

The mansard roof – The mansardA room built in an attic, generally under a double-slope roof and which has walls at an angle and a low ceiling. roof or French roof can have two slopes or can be a hip roof or a pavilion roof (pyramidal hipped roof) covering a square or almost square building. This roof owes its fame to French architect François Mansart who made it popular in the 17th century. Its great advantage is that it offers the possibility of optimizing the use of the attic space: its lighter and less cumbersome frame makes for a higher and larger attic. There is an abundance of such roofs in the Baie-Saint-Paul region. When mansardA room built in an attic, generally under a double-slope roof and which has walls at an angle and a low ceiling. roofs were first built in the 17th century, they were covered with slate or wood shingles. Later on, when they became popular again in the second half of the 19th century, metal was used: tin with rods for the low-angle upper slope or deck, and “tôle à la canadienne”, whose break angle is more pronounced, which minimizes risks of water infiltration.

Mansard Roofing

The false mansard roof– This type of roof is typical of the Montréal region, particularly in the Plateau Mont-Royal area. It looks like a mansardA room built in an attic, generally under a double-slope roof and which has walls at an angle and a low ceiling. roof when viewed from street level, but in reality only the break is real while the upper-slope or deck is in fact a flat roof sloping towards the back of the building to facilitate water drainage. The break of the false mansardA room built in an attic, generally under a double-slope roof and which has walls at an angle and a low ceiling. roof, a typical roof at the turn of the 20th century, was covered with slate and featured dormersOpening with a glass pane located on the slope of a roof to illuminate / ventilate a space.. Needless to say that this roof shape allowed for a maximum use of interior space, while maintaining the aesthetic and visual qualities of the mansardA room built in an attic, generally under a double-slope roof and which has walls at an angle and a low ceiling. roof.

The sloped flat roof – At the beginning of the 20th century, the massive development of sawmills and products such as tar, derived from petroleum, brought about the introduction of slightly sloped, almost flat, roofs. Plain wood beams, smaller than the big pieces used in traditional framing, reduced the time needed to build roof framing, and simplified the process. Several layers of tarred membranes ensured the roof’s waterproofing. Additionally, the roof is slightly sloped either toward the back of the building or toward the center, where water is drained by pipes. A ventilated attic keeps the roof in good condition and humidity-free.

The pyramidal, hipped roof– This roof has a pyramidal shape, with the four slopes creating an apex or very short ridge at the top. The four slopes can be plain, that is, straight down, or broken, as is the case of a mansardA room built in an attic, generally under a double-slope roof and which has walls at an angle and a low ceiling. roof. In some cases, the upper slopes are crowned with a deck, or topped with a skylightDevice, often in the shape of a dome, placed on a roof to illuminate a dark room or a windowless room; also used to aerate or to provide an exit out if it is an opening skylight., a turretSmall tower attached to a building, sometimes built overhanging., or a belvedereHigh up construction or terrace with an unobstructed view..

The types of roofs we have just described are the ones most commonly found. There are numerous other kinds of roofs that can be seen in public buildings and accessory buildings, and they contribute to enhancing the architectural cityscape. Among the examples are the conical roof; the dome, whose slope creates a curved surface; the saw-tooth roof, characteristic of industrial buildings; and the steeple, typical of churches.

Roof covering materials

The first Europeans to arrive here made use of available and abundant materials to cover their roofs: thatch, bark, and wood. There are still a few examples of thatched roofs in the Charlevoix and Yamachiche regions. Wood shingles have always been used, but mainly in rural areas. As for wood, much in use in the 18th century, it was soon abandoned because it was not waterproof and because of the risk of fire. As soon as it became available, sheet metal became the preferred roof covering material. Among the metal coverings, the “tôle à la canadienne” was widely used in Québec, beginning in the mid-18th century. The use of tin sheets with rods began near the end of the 19th century, as large tin sheets began to be produced. In the last quarter of the 19th century, another method became available: a double folding of the sheet metal, i.e. crimped first, then folded up. This sort of covering is called standing seam tin roof. Finally, the industrialization of building techniques in the early 20th century made other products available. Stamped sheet metal (tin being the most common) featured designs imitating fish scales, slate tiles, and other motifs. Other metals, such as copper, sometimes replaced tinplate, the first metal to be used for roofing, or galvanized tin, which appeared later.

Proceed carefully

A roof’s stability depends on the good condition and good design of the framing that supports it. Often, a close inspection of an attic will reveal that over the years, parts of the framing have undergone modification or suffered from prolonged water infiltration. The stability and cohesiveness of the entire frame can be affected, resulting in partial or complete deformation or sagging of the roof. Sometimes, pieces of the structural frame have been removed in order to introduce a dormerOpening with a glass pane located on the slope of a roof to illuminate / ventilate a space. or simply to open up the interior space. Sooner or later, these issues have to be corrected in order to ensure that the roof framing is structurally sound and secure. Homeowners should conduct a careful inspection of the attic’s roof framing to identify any evidence of water infiltration or decay, or any piece of the framing that may be missing or that shows signs of rotting. Ideally, such an inspection should be conducted every fall to detect any potential problem. Since the roof is rather inaccessible, and hard to observe from the ground, people sometimes simply assume that it is in good shape. Because the roof is under considerable pressure because of rain, snow, and ice, it is very important to keep track of its condition.

François Varin is an architect.
Excerpts from an article published in the magazine Continuité, n° 63, 1995