Roofing Info For Residents of Atlantaby Bill Mixon on 05/27/15
The characteristics of a roof are dependent upon the purpose of the building that it covers, the available roofing materials and the local traditions of construction and wider concepts of architectural design and practice and may also be governed by local or national legislation. In most countries a roof protects primarily against rain. A verandah may be roofed with material that protects against sunlight but admits the other elements. The roof of a garden conservatory, protects plants from cold, wind and rain but admits light.
Domestic roof construction is the framing and roof covering which is found on most suburban detached houses in cold and temperate climates. Such roofs are mostly built with timber, take a number of different shapes, and are covered with a variety of materials.
The shape of roofs differs greatly from region to region. The main factors which influence the shape of roofs are the climate and the materials available for roof structure and the outer covering.
The basic shapes of roofs are flat, skillion, gabled, hipped, arched and domed. There are many variations on these types. Roofs constructed of flat sections that are sloped are referred to as pitched roofs (generally if the angle exceeds 10 degrees). Pitched roofs, including gabled, hipped and skillion roofs, make up the greatest number of domestic roofs. Some roofs follow organic shapes, either by architectural design or because a flexible material such as thatch has been used in the construction.
Modern timber roofs are mostly framed with pairs of common rafters or prefabricated wooden trusses fastened together with truss connector plates. Timber framed and historic buildings may be framed with principal rafters or timber roof trusses. Roofs are also designated as warm or cold roof depending on how they are designed and built with regard to thermal building insulation and ventilation. The steepness or roof pitch of a sloped roof is determined primarily by the roof covering material and aesthetic design. roofs actually slope up to approximately ten degrees to shed water. Flat roofs on houses are primarily found in arid regions.
In high wind areas, such as where a cyclone or hurricane may make landfall, the main engineering consideration is to hold the roof down during severe storms. Every component of the roof, as of course the rest of the structure, has to withstand the uplift forces of high wind speeds. This is accomplished by using metal ties fastened to each rafter or truss. This is not normally a problem in areas not prone to high wind.