Roofing refers to any one of a number of methods used to strengthen the foundation of a building and provide a protective surface. A roof, generally speaking, is just the apex covering of a structure, comprising all structures and materials needed to support it upon uprights, overhangs, or other supports on the building’s wall. A roofing system may be used to provide protection from the weather, such as snow or rain. It may also provide insulation to reduce the energy costs incurred in cooling and heating the structure.
Rooftops are usually the strongest part of a roof structure, but they are usually not attractive. There are many different types of roof structure, from flat and sloped roofs to planter and gable roofs to multi-sloped and pitched roofs. The roofing materials vary widely, as well. Aluminum, slate, clay tile, wood, stone, bricks, gypsum, concrete, asphalt, and insulated concrete forms the major materials used for roofs in the United States. They are differentiated by type of installation, such as attachment to the ceiling, attachment to the wall or floor, or use of flashing and skylights. The roofing systems are further divided into different categories according to the kinds of materials used for their installation:
Flat roofs have only three layers: the first layer is the fascia, containing plywood or membrane that allows water to drain away from the structure, the second layer is the sheathing, containing either wood or membrane, the third layer is the underlying earth layer. The flat roofs have very little insulation, since there is no difference between the exterior and interior of the same roofing system. The earth roofing is often installed with flashing and skylights. It is also a good choice for low slope areas.
Roof construction is more complicated in polygons than in flat roofs. In polygons, there are two types of roofing systems: parallel and nonslip. The polygonal roofs are the simplest and least expensive to install. They consist of two long side walls with flat roofs on each side and a bottom wall with a lip or ridge cap, which allows water drainage.
The other type of roofing system is called wood shingles. Wood shingles are also simple and economical to install, with the exception of having ventilation. Wood shingles are more complex and costly to install, mainly because of materials and labor needed. The most common type of wood shingles is asphalt. Since it is a synthetic material, it does not permit moisture to pass through it.
Roof construction is very important in the United States, especially in areas prone to hurricanes and tornadoes. There are many choices in roofing material available for builders to use. And in the last few years, new technologies have made the job even easier. Asphalt shingles are still the most popular roofing material for residential and commercial buildings.