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roof,overhead covering of a building with its framework support. Various methods of construction, such as are suited to different climates, have diversified exterior and interior architectural effects. A roof may be flat, as in hot, dry areas where the shedding of rain and snow does not present a problem, e.g., in ancient Mesopotamia, Egypt, and in the SW United States. Modern structural materials and methods have made flat-roof construction practical in nearly any climate, with the development of concrete slabs, efficient drains, and waterproofing materials. On the other hand, steeply sloping roofs are still commonly found in N New England, in the Scandinavian countries, and in other regions where it is necessary to shed snow. Variations of the pitched roof are in gable, gambrel, mansard, or hip (having four sides sloping from a short ridge or center) form. The pitched roof may be of the lean-to type, as in a simple shed, or it may achieve the dignity and aspiration of a domedome,
a roof circular or (rarely) elliptical in plan and usually hemispherical in form, placed over a circular, square, oblong, or polygonal space. Domes have been built with a wide variety of outlines and of various materials.
..... Click the link for more information. or spirespire,
high, tapering structure crowning a tower and having a general pyramidal outline. The simplest spires were the steeply pitched timber roofs capping Romanesque towers and campaniles. In later Romanesque architecture the spire was commonly octagonal, topping a square tower.
..... Click the link for more information. and embody such features as the dormer window, cupola, or minaret. Pointed-roof construction includes the tie-beam, trussed-rafter, collar-beam, and hammer-beam types. English churches and halls afford many examples of these various methods, some of which have highly decorative open-timber interiors. The simplest roof covering is thatch (of straw, palm leaves, or other fibers) used by the peasants of many lands. Other finishing materials include wood (usually shingles), tile, slate, tin, lead, zinc, copper, felt, and tar. A roof's ridge is the point where the rafters meet; its principals, the purlins, resting on center or side posts, support the rafters; a valley or trough is formed by the junction of two slopes (e.g., where an ell joins the main structure). The eaves, or overhang, carry gutters or themselves drain water beyond the walls, and in the chalet and bungalow they are very wide. The concave curve of East Asian roofs is said to follow the graceful lines of a sagging tent. The classical Greek roof was of marble slabs upon timber framing and sloped gently. Early Roman roofs also were timber framed (as in the basilicas), but vault and dome construction (as in the Pantheon) were prominent in later buildings. The pointed arch and vaulting gave the slope to the Gothic roofs of Europe, while roofs in Renaissance Italy, except those with domes, were concealed, but France and Germany of this period emphasized the gable. Stepped gables are characteristic of Dutch and German roofs. Cone-topped turrets are common on the steep roofs of French châteaus. Roof ornamentation consisted of finials, crockets, crestings, gable crosses, bosses, and fantastic gargoyles (that also served as waterspouts). Roof decoration was particularly elaborate in early Asian and Gothic architecture. In contemporary architecture, roofs can span great distances with little material and few supports because of advances in the methods of using concrete and steel. Green roofs, which have used mainly since the late 1980s, lessen the environmental impact of traditional roofs, especially in urban areas. The roof surface of a building is covered with soil or another growing medium that is planted with grasses, flowers, or other plants. Green roofs reduce storm water runoff, reduce roof heating (mitigating urban "heat islands" and lowering cooling costs) and insulate the building (lowering heating and cooling costs).
See T. Hamlin, Forms and Functions of Twentieth-Century Architecture (1952).
Dutch gambrel roof
pyramidal hipped roof
umbrella shell roof
the top enclosing structure of a building. It consists of a supporting element (rafters, trusses, purlins, panels, and so on), which transmits the load from snow, wind, and the weight of the roof itself to the walls and separate supports, and an outer envelope, or roofing.
Roofs are made with or without attics or lofts. A roof with a loft may be heated or unheated. An unheated roof protects a building only from atmospheric precipitation; thermal protection of the upper floor spaces is provided by the attic ceiling. In roofs without lofts or attics, the roof itself fulfills the function of the attic ceiling; in this case, the roof is called a ceiling floor, covering, or combined roof. The inclined surface (for water runoff) of the roof is called the slope (pitch); the line of intersection of the two slopes that form the outer slope angle is called the rib, and the line of intersection forming the inner slope angle is called the valley; the upper horizontal rib of the roof is called the ridge, or crest. The pitch of a roof is determined by the roofing material, the climatic conditions, and architectural and service requirements.
(in mining), rock located above a mineral seam. A thin layer of barren rock that lies directly above a mineral seam and crumbles spontaneously soon after its removal is known as a false roof. In coal mining, a distinction is also made between the nether roof (layers of barren rock located directly above a coal seam, whose controlled destruction occurs after the face advances) and the main roof (layers of rock located above the nether roof, whose destruction is virtually uncontrollable and takes place over long intervals of time, depending on the strength and thickness of the rock).
(in Russian, pokrytie), the upper structure that separates the rooms of a building from the outside and protects them from the outside environment. The term pokrytie is used mainly to designate the roof of industrial buildings, whereas in the construction of residential and public buildings the term krysha is used more frequently. As a rule, a roof consists of the roofing material, insulation, moistureproofing, and a supporting structure. Some parts of the structure, such as decking constructed of light or cellular concrete, may also provide thermal insulation and, sometimes, moistureproofing.
The supporting structure is the most important component of a roof, since it determines the shape (flat, domed, or vaulted) of the roof and the internal and external appearance of the building. There are many different types of supporting structures, including horizontal slabs (flat, corrugated, or hollow) resting on beams; rafters (flat or spatial); thin-walled shells; and folding, suspended, pneumatic, and other structures. The supporting structures of a roof can be made of reinforced concrete (precast or cast at the construction site), metal, asbestos cement, and, less frequently, wood. In modern construction engineering, supporting structures are being produced that are longer, wider, and lighter than those produced previously. Their erection is also less labor-intensive. Among the methods being introduced is the use of metal intersective structures; large, prefabricated, thin-walled shells; suspended structures; long panels; and contoured metal slabs.
The insulation usually consists of sheeting (lightweight aggregate concrete, perlite concrete, or foam concrete) or loose materials (clay filler, blast furnace slag, or microporous rubber). Cellular concrete, cast at the building site, is used less frequently. Moistureproofing is usually provided to protect the insulation from being penetrated by the moisture in the rooms (particularly in industrial buildings). It usually consists of one or two layers of tar paper applied over bituminous cement. The accumulation of moisture can also be prevented by the use of ventilated roofs, which have openings and vents leading to the outside.
The uses of a building determine whether the roof has skylights, one or several spans, or interior or exterior drainage. Some roofs are designed as flat decks with parking facilities, restaurants, playing fields, solaria, or pools.
REFERENCESKonstruktsii grazhdanskikh zdanii. Edited by M. S. Tupolev. Moscow, 1968.
Konstruktsii promyshlennykh zdanii. Edited by A. N. Popov. Moscow, 1972. Z. A. Kazbek-Kaziev
What does it mean when you dream about a roof?
A roof symbolizes a cover for that which needs protecting. It can also indicate a barrier between two states of consciousness. A leaking roof sometimes means that there is new information dripping through.