12. MAIN ROOF. DESIGN LOADS

A roof structure is part of your building envelope. It's the covering on the uppermost part of the building or shelter which provides protection from pets and weather, rain or snow notably, but also heat, sunlight and wind. The word denotes the framing or composition which facilitates that covering also.[1]The characteristics of an roof are dependent upon the goal of the building that it covers, the available roofer materials and the local traditions of development and wider concepts of architectural design and practice and may also be governed by local or countrywide legislation. In most countries a roof protects mainly against rain. A verandah may be roofed with material that protects against sunlight but admits the other elements. The roof of any garden conservatory protects plants from cold, wind, and rain, but admits light.Shack manufactured from date hand branches at Neot Semadar, IsraelA roof structure could also provide additional liveable space, for example a roofing garden.The elements in the design of a roof covering are:the materialthe constructionthe durabilityThe material of an roof may range between banana leaves, wheaten straw or seagrass to laminated a glass, copper (see: copper roof), aluminium sheeting and pre-cast concrete. In many parts of the entire world ceramic tiles have been the predominant roof material for centuries, if not millennia. Other roof covering materials include asphalt, coal tar pitch, EPDM rubber, Hypalon, reboundable foam, PVC, slate, Teflon textile, TPO, and lumber shakes and shingles.The construction of an roof depends upon its method of support and how the underneath space is bridged and set up roof is pitched. The pitch is the perspective at which the roof rises from its minimum to highest point. Most US home architecture, except in very dry out locations, has roofs that are sloped, or pitched. Although modern construction elements such as drainpipes may remove the need for pitch, roofs are pitched for reasons of custom and appearance. So the pitch is partly dependent upon stylistic factors, and partially to do with practicalities.Some types of roof covering, for example thatch, need a steep pitch to become durable and waterproof. Other types of roofing, for example pantiles, are unstable on the steeply pitched roof but provide excellent weather protection at a relatively low angle. In parts where there is little rainwater, an almost flat roof with a slight run-off provides enough protection against an occasional downpour. Drainpipes remove the need for a sloping rooftop also.Somebody who specializes in rooftop construction is called a roofer.The durability of the roofing is a matter of concern because the rooftop is often the least accessible part of any building for purposes of repair and renewal, while its destruction or destruction can have serious effects.Because the purpose of a roof top is to safeguard people and their property from climatic elements, the insulating properties of an roof top are a consideration in its composition and the choice of roofing material.Some roof materials, those of natural fibrous materials especially, such as thatch, have excellent insulating properties. For all those that not, extra insulation is often installed under the exterior covering. In developed countries, the majority of dwellings have a ceiling installed under the structural members of the roof. The goal of a roof is to insulate against temperature and cold, sound, dirt and grime and frequently from the droppings and lice of parrots who frequently choose roofs as nesting places.Cement tiles can be utilized as insulation. When installed departing a space between your tiles and the rooftop surface, it can reduce home heating caused by sunlight.Forms of insulation are clear plastic or sensed sheeting, sometimes with a reflective surface, installed straight below the tiles or other materials; synthetic foam batting laid above the ceiling and recycled paper products and other such materials that can be inserted or sprayed into roof cavities. So called Cool roofs have become more and more popular, and in some full cases are mandated by local codes. Cool roofs are defined as roofs with both high reflectivity and high thermal emittance.Poorly insulated and ventilated roof can have problems with problems like the formation of glaciers dams surrounding the overhanging eaves in cold weather, causing drinking water from melted snow on higher elements of the roof to penetrate the roofing materials. Ice dams occur when temperature escapes through the uppermost part of the roof, and the snow at those things melts, refreezing as it drips across the shingles, and collecting in the form of ice at the low points. This can cause structural destruction from stress, including the damage of drainage and gutter systems.

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As you can see, I scaled the loads by a factor of 10. I had to, for

Roof Snow Load Building Codes http://archive.constantcontact.com/fs035

cca2013fallcpm [licensed for noncommercial use only] / Shan Sanby Yu

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