Roofs have one functional purpose: sheltering the home from weather conditions whether it is rain, snow or sun. Without a roof the water would run down into the interior of the home and destroy the contents as well as, in time, denaturing the walls whether they are wood, concrete or masonry. Almost every structure on the planet needs a roof whether it be a stadium or a bird house and finding the right roofing contractor is crucial.
Historical paintings have alluded to the fact that after early man emerged from cave dwelling their roofs were a lean-to design, sometimes anchored on a tree but most of the time on a rock face. Framework was very important in roof architecture and this showed in the dwellings of aboriginal people the world over. For example, the Iroquois and aboriginal peoples of the eastern part of North America built lodges framed with timbers. The roofing materials were shingles made from various materials including skins. In the tropical areas roofs were framed with bamboo and shingled with large leaves.
The settling of North America by Europeans brought their roofing styles with them but they copied the natives for the frame work. So the gabled-style roof became a norm for simple log homes and this trend continues to this day.
The framework for the gable roof is a series of rafters spaced 12 -16” inches apart and decked with a sheathing of plywood, oriented strand board (osb) or, in the past, tongue-and-groove lumber. The roof sits on the walls that transfer the load to the foundation.
The downside of gable roofs is that they can act as a giant sail in the face of high winds that can find an anchor under the eaves. The upward pressures cause a failure in the truss system that is designed for downward weight.
The barn-style roof, also called the “Gambrel,” is like a gable roof except each roof side is divided into two parts which slope in at different angles. The upper part of this slope maintains a shallow angle while the lower part is quite steep. Back in the days when the upper part of barns held silage for the animals this structural design gains headroom on the upper level enabling more usable space. So this design also works in homes where the upper levels are not encumbers by a low, sloping ceiling.
Because of their height and upper gable surface area they also can trap winds cause them to defeat on the gabled ends. The good news is that the eave space is slim so high winds cannot rip at it.
This is a type of roof where all sides slope gently downward. Square versions of this design are shaped like a pyramid, in other words each roof triangle has the exact same dimensions. If the roof style is on a rectangular home then the opposite sides are equal.
Appearing now mostly on cottages and bungalows this style was very popular for bungalows in the 1950's as they were easy to build. Supporting the roof is a complex array of trusses so that building the roof takes more time. In addition, storage space is limited by the loads of timber in the attic. However, this makes the roof stronger and, in addition to its low profile, is more likely to withstand hurricane-force winds than the normal, gabled roofs. A “mansard” roof is a hip roof with two different roof styles.
The downside with hip roofs is that they are susceptible to snow loads because the slope is so shallow. This is offset by the incredible strength of the truss system.
The flat roof in many instances isn't a totally horizontal roof. Many commercial buildings have slightly inclined flat roofs to allow water to run off. The main feature about a flat roof is that the total roofing deck is at the same level.
When they were first conceived for commercial use the roofs were covered with tar and gravel to give the protection some substance and strength. However, if the water was allowed to pool minute cracking due to sun and cold could allow water to leak in. Modern roofing techniques have all but eliminated this weakness using a continuous rubber or rubber-like membrane that is laid over the whole surface. These coatings are also successful in “green” applications, allowing grass and shallow-rooted shrubs to grow in a natural environment on top. Moisture from rain, instead of pooling, is kept up in the root system of the plant life.
Roofing is a specialized occupation and a roofing contractor can direct you to the type of material that is best for your home. When dealing with the plans for a new home the architect and engineer will take into account the type of climate when designing the roof.