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Tar paper is a heavy-duty paper used in construction. Tar paper is made by impregnating paper or fiberglass mat with tar, producing a waterproof material useful for roof construction. Tar paper is distinguished from roofing felt, which is impregnated with asphalt instead of tar, but these two products are used the same way, and their names are sometimes used informally as synonyms.
Tar paper has been in use for centuries. Originally, felt was made of recycled rags, but modern felt is made of recycled paper products, typically cardboard, and sawdust.
The most common product is #15 felt. Before the oil crisis,[ which? ] felt weighed about 15 pounds (6.8 kg) per square, hence the asphalt-impregnated felt was called "15-pound felt" (15#). Modern, inorganic mats are no longer the same weight, and to reflect this fact, the new felts are called "number 15 felt" (#15). Modern #15 mats can weigh from 7.5 to 12.5 pounds (3.4 to 5.7 kg) pounds per square, depending on the manufacturer and the standard to which felt is made (such as ASTM, CGSB, or none). A thicker and stronger variant, once known as 30-pound felt (30#), is number 30 felt (#30), which usually weighs 16 to 27 pounds (7.3 to 12.2 kg) per square.
Tar paper is more accurately a Grade D building paper—the Grade D designation is derived from a federal specification in the United States—and is widely used in the West.[ which? ] Building paper is manufactured from virgin kraft paper, unlike felts, and then impregnated with asphalt. The longer fibers in the kraft paper allow for a lighter-weight product with similar and often better mechanical properties than felt. Grade papers are rated in minutes: the amount of time it takes for a moisture-sensitive chemical indicator to change color when a small boat-like sample is floated on water. Common grades include 10-, 20-, 30-, and 60-minute. The higher the rating, the heavier and more moisture-resistant the paper. A typical 20-minute paper will weigh about 3.3 pounds (1.5 kg) per square, a 30-minute paper 3.75 pounds (1.70 kg) per square, and a 60-minute paper about 6 pounds (2.7 kg) per square. The smaller volume of material, however, does tend to make these papers less resistant to moisture than heavier felts.
Tar paper is used as underlayment with asphalt, wood, shake, and other shingles, or even gravel, since tar paper itself isn't particularly wind- or sun-resistant. It is sold in rolls of various widths, lengths, and thicknesses – 3-foot-wide (0.91 m) rolls, 50 or 100 feet (15 or 30 m) long and "15 lb" (7 kg) and "30 lb" (14 kg) weights are common in the U.S. – often marked with chalk lines at certain intervals to aid in laying it out straight on roofs with the proper overlap (more overlap for flatter roofs).
It can be installed in several ways, such as staples or roofing nails, but it is also sometimes applied in several layers with hot asphalt, cold asphalt (adhesive), or non-asphaltic adhesives.
Older construction sometimes used a lighter-weight tar paper, stapled up with some overlap, as a water- and wind-proofing material on walls, but modern carpenters more often use 8-or-10-foot (2.4 or 3.0 m) widths of housewrap.
In the 19th and early 20th centuries, tar paper shacks consisting of wooden frames covered with tar paper were a common form of very low-cost housing in the rural United States and Canada.
Asphalt, also known as bitumen, is a sticky, black, highly viscous liquid or semi-solid form of petroleum. It may be found in natural deposits or may be a refined product, and is classed as a pitch. Before the 20th century, the term asphaltum was also used. The word is derived from the Ancient Greek ἄσφαλτος ásphaltos. The largest natural deposit of asphalt in the world, estimated to contain 10 million tons, is the Pitch Lake located in La Brea in southwest Trinidad, within the Siparia Regional Corporation.
Corrugated fiberboard or corrugated cardboard is a type of packaging material consisting of a fluted corrugated sheet and one or two flat linerboards. It is made on "flute lamination machines" or "corrugators" and is used for making corrugated boxes. The corrugated medium sheet and the linerboard(s) are made of kraft containerboard, a paperboard material usually over 0.25 millimetres (0.01 in) thick.
Oriented strand board (OSB) is a type of engineered wood similar to particle board, formed by adding adhesives and then compressing layers of wood strands (flakes) in specific orientations. It was invented by Armin Elmendorf in California in 1963. OSB may have a rough and variegated surface with the individual strips of around 2.5 cm × 15 cm, lying unevenly across each other, and is produced in a variety of types and thicknesses.
Drywall is a panel made of calcium sulfate dihydrate (gypsum), with or without additives, typically extruded between thick sheets of facer and backer paper, used in the construction of interior walls and ceilings. The plaster is mixed with fiber ; plasticizer, foaming agent; and additives that can reduce mildew, flammability, and water absorption.
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 National Roofing Contractors Association defines a low-slope roof as having a slope of 3 in 12 (1:4) or less.
Underlay may refer to flooring or roofing materials, bed padding, or a musical notation.
Waterproofing is the process of making an object or structure waterproof or water-resistant so that it remains relatively unaffected by water or resisting the ingress of water under specified conditions. Such items may be used in wet environments or underwater to specified depths.
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.
A vapor barrier is any material used for damp proofing, typically a plastic or foil sheet, that resists diffusion of moisture through the wall, floor, ceiling, or roof assemblies of buildings and of packaging to prevent interstitial condensation. Technically, many of these materials are only vapor retarders as they have varying degrees of permeability.
Fiberboard or fibreboard is a type of engineered wood product that is made out of wood fibers. Types of fiberboard include particle board or low-density fiberboard (LDF), medium-density fiberboard (MDF), and hardboard.
Nonwoven fabric is a fabric-like material made from staple fibre (short) and long fibres, bonded together by chemical, mechanical, heat or solvent treatment. The term is used in the textile manufacturing industry to denote fabrics, such as felt, which are neither woven nor knitted. Some non-woven materials lack sufficient strength unless densified or reinforced by a backing. In recent years, non-wovens have become an alternative to polyurethane foam.
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.
Grammage and basis weight, in the pulp and paper industry, are the area density of a paper product, that is, its mass per unit of area. Two ways of expressing grammage are commonly used:
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.
Bituminous waterproofing systems are designed to protect residential and commercial buildings. Bitumen is a mixed substance made up of organic liquids that are highly sticky, viscous, and waterproof. These systems are sometimes used to construct roofs, in the form of roofing felt or roll roofing products.
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. The installation process, known as Torch On Roofing, is often used on commercial properties in North America.
A stone coated metal roof is a roof made from steel or some other metal; the metal is then coated with stone chips and attached to the steel with an acrylic film. The goal is a more durable roof that still retains the aesthetic advantages of a more traditional roofing material
The Type 2 12 cm mortar is a smooth bore, muzzle-loading type mortar which, except for the firing mechanism, closely resembles the conventional Stokes-Brandt 81 mm mortar. The bipod and cradle of the two types of mortars are identical, except for size and the fact that the bipod legs can be removed as a unit from the cradle of the 120 mm mortar. The large, ribbed base plate has only one socket for the spherical projection on the barrel. A Type 2 120 mm mortar was reported captured at Leyte.