Asphalt roll roofing or membrane is a roofing material commonly used for buildings that feature a low sloped roof pitch in North America. The material is based on the same materials used in asphalt shingles; an organic felt or fiberglass mat, saturated with asphalt, and faced with granular stone aggregate. [1]
Roll roofing is usually restricted to a lightweight mat compared to shingles, as it must be rolled for shipment. Rolls are typically 36 inches (91 cm) by 33 feet (10 m) in size.[ citation needed ] Due to its light weight compared to shingles, roll roofing is regarded as an inexpensive, temporary material. Its broad width makes it vulnerable to temperature-induced shrinkage and tearing as it expands and contracts.
Other names for this material are "asphalt prepared roofing, asphaltic felt, cold-process roofing, prepared roofing, rolled roofing, rolled strip roofing, roofing felt, sanded bituminous felt, saturated felt, self-finished roofing felt." [2]
Roll roofing is normally applied parallel to the eaves from the bottom of the roof upwards, lapping each new roll in the same manner as shingles. Its use is restricted to roofs with a pitch of less than 2:12. To avoid penetrating the exposed membrane with nails, adhesive or "lap cement" must be used at the bottom edge to keep it from being lifted by the wind. The upper edge of the roll is nailed and covered by the next roll.[ citation needed ]
Historical Development: The asphalt-prepared roofing industry had its beginning in Sweden more than a century ago, when roof boards were covered with paper treated with wood tar. Later, in Germany, paper was coated with varnish, surfaced with finely ground mineral matter, and used as a roofing material. In the United States, asphalt was used to waterproof duck fabric in the early part of the nineteenth century. The first recorded use of melted asphalt for impregnating duck fabric in this country was in 1844. About this time roofs composed of sheets of sheathing paper treated with pine tar and pine pitch, and surfaced with fine sand, were being laid. Coal tar and coal- tar pitch were later substituted for the pine tar. These were the forerunners of the present asphalt and coal-tar-pitch built-up roofs. It is not known definitely when felt was first substituted for sheathing paper or when asphalt was first used as the impregnating agent, but it is known that the first asphalt-prepared roofing, that is, roofing manufactured ready to apply, was marketed in 1893. The first roofing was not surfaced.
Mineral-surfaced, asphalt-prepared roofing appeared in 1897. The first asphalt shingles, mineral-surfaced, were made in 1901, and about this time slate grain less were first used as a surfacing material. Asphalt shingles did not come into general use until about 1911. During 1939, thirty-two manufacturers, representing about 95 percent of the asphalt-prepared roofing industry, produced 34,225,187 squares ^ of prepared roofing. Almost one third of this, 11,173,856 squares, was in the form of asphalt shingles, which are used principally for roofing dwellings. The shingles produced in 1939 were sufficient to cover more than 1,000,000 dwellings, assuming an average size of 10 squares per roof. In two surveys of roofing materials in 20 Eastern States, - made during 1938, the kinds of roofing materials on 20,841 dwellings along 4,038 miles of highway were tabulated. Of these dwellings, 6,549 were roofed with asphalt shingles and 2,381 with asphalt roll roofing. Thus, almost 43 percent of these dwelling were roofed with asphalt-prepared roofing. Statistics of the Bureau of the Census indicate that asphalt-prepared roll roofing and shingles constituted slightly less than half of all the roofing materials sold during 1937. [3]
The main uses are:
Several variations of bitumen roofing felt are available.
Fibre content:
Bitumen:
Underside:
Topping:
Bitumen is an immensely viscous constituent of petroleum. Depending on its exact composition it can be a sticky, black liquid or an apparently solid mass that behaves as a liquid over very large time scales. In American English, the material is commonly referred to as asphalt. Whether found in natural deposits or refined from petroleum, the substance is classed as a pitch. Prior to the 20th century the term asphaltum was in general use. The word derives from the ancient Greek ἄσφαλτος ásphaltos, which referred to natural bitumen or pitch. The largest natural deposit of bitumen in the world is the Pitch Lake of southwest Trinidad, which is estimated to contain 10 million tons.
In woodworking and construction, a nail is a small object made of metal which is used as a fastener, as a peg to hang something, or sometimes as a decoration. Generally, nails have a sharp point on one end and a flattened head on the other, but headless nails are available. Nails are made in a great variety of forms for specialized purposes. The most common is a wire nail. Other types of nails include pins, tacks, brads, spikes, and cleats.
A roof is the top covering of a building, including all materials and constructions necessary to support it on the walls of the building or on uprights, providing protection against rain, snow, sunlight, extremes of temperature, and wind. A roof is part of the building envelope.
A radiant barrier is a type of building material that reflects thermal radiation and reduces heat transfer. Because thermal energy is also transferred by conduction and convection, in addition to radiation, radiant barriers are often supplemented with thermal insulation that slows down heat transfer by conduction or convection.
Tar paper is a heavy-duty paper used in construction. Tar paper is made by impregnating paper with tar, producing a waterproof material useful for roof construction. Tar paper is similar to roofing felt, historically a felt-like fabric made from recycled rags impregnated with melted asphalt, and today evolving into a more complex underlayment of synthetic mesh or fiberglass strands waterproofed by synthetically enhanced asphalt.
A flat roof is a roof which is almost level in contrast to the many types of sloped roofs. The slope of a roof is properly known as its pitch and flat roofs have up to approximately 10°. Flat roofs are an ancient form mostly used in arid climates and allow the roof space to be used as a living space or a living roof. Flat roofs, or "low-slope" roofs, are also commonly found on commercial buildings throughout the world. The U.S.-based National Roofing Contractors Association defines a low-slope roof as having a slope of 3 in 12 (1:4) or less.
Tar is a dark brown or black viscous liquid of hydrocarbons and free carbon, obtained from a wide variety of organic materials through destructive distillation. Tar can be produced from coal, wood, petroleum, or peat.
Asbestos cement, genericized as fibro, fibrolite, or AC sheet, is a composite building material consisting of cement and asbestos fibres pressed into thin rigid sheets and other shapes.
Roof shingles are a roof covering consisting of individual overlapping elements. These elements are typically flat, rectangular shapes laid in courses from the bottom edge of the roof up, with each successive course overlapping the joints below. Shingles are held by the roof rafters and are made of various materials such as wood, slate, flagstone, metal, plastic, and composite materials such as fibre cement and asphalt shingles. Ceramic roof tiles, which still dominate in Europe and some parts of Asia, are still usually called tiles. Roof shingles may deteriorate faster and need to repel more water than wall shingles. They are a very common roofing material in the United States.
Wood shingles are thin, tapered pieces of wood primarily used to cover roofs and walls of buildings to protect them from the weather. Historically shingles, also known as shakes, were split from straight grained, knot free bolts of wood. Today shingles are mostly made by being cut which distinguishes them from shakes, which are made by being split out of a bolt.
A metal roof is a roofing system featuring metal pieces or tiles exhibiting corrosion resistance, impermeability to water, and long life. It is a component of the building envelope. The metal pieces may be a covering on a structural, non-waterproof roof, or they could be self-supporting sheets.
Domestic roof construction is the framing and roof covering which is found on most detached houses in cold and temperate climates. Such roofs are built with mostly timber, take a number of different shapes, and are covered with a variety of materials.
Housewrap, also known by the genericized trademark homewrap, generally denotes a modern synthetic material used to protect buildings. Housewrap functions as a weather-resistant barrier, preventing rain or other forms of moisture from getting into the wall assembly while allowing water vapor to pass to the exterior. If moisture from either direction is allowed to build up within stud or cavity walls, mold and rot can set in and fiberglass or cellulose insulation will lose its R-value due to heat-conducting moisture. House wrap may also serve as an air barrier if it is sealed carefully at seams.
An asphalt shingle is a type of wall or roof shingle that uses asphalt for waterproofing. It is one of the most widely used roofing covers in North America because it has a relatively inexpensive up-front cost and is fairly simple to install.
A roof coating is a monolithic, fully adhered, fluid applied roofing membrane. Many roof coatings are elastomeric, that is, they have elastic properties that allow them to stretch and return to their original shape without damage.
Membrane roofing is a type of roofing system for buildings, RV's, Ponds and in some cases tanks. It is used to create a watertight covering to protect the interior of a building. Membrane roofs are most commonly made from synthetic rubber, thermoplastic, or modified bitumen. Membrane roofs are most commonly used in commercial application, though they are becoming increasingly common in residential application.
Sarking is an English word with multiple meanings in roof construction:
Bituminous waterproofing systems are designed to protect residential and commercial buildings. Bitumen is a material made up of organic liquids that are highly sticky, viscous, and waterproof. Systems incorporating bituminous-based substrates are sometimes used to construct roofs, in the form of "roofing felt" or "roll roofing" products.
An ice dam is an ice build-up on the eaves of sloped roofs of heated buildings that results from melting snow under a snow pack reaching the eave and freezing there. Freezing at the eave impedes the drainage of meltwater, which adds to the ice dam and causes backup of the meltwater, which may cause water leakage into the roof and consequent damage to the building and its contents if the water leaks through the roof.
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