Accelerated weathering – the exposure of a specimen to a specified environment for a specified time with the intent of producing, in a shorter time period, effects similar to actual weathering.
Aggregate – crushed stone, crushes slag, or water-worn gravel used for surfacing a built-up roof: (2) any granular material.
Alligatoring – The cracking of the surfacing bitumen on a built-up roof, producing a pattern of cracks similar to an alligator’s hide, the cracks may not extend through the surfacing bitumen.
Anionic emulsion – an emulsion in which the emulsifying system established and predominance of negative charges in the discontinuous phase.
Application rate – the quantity (mass, volume, or thickness) of materials applied per unit area.
Artificial weathering – exposure to conditions, which may be cyclic, involving temperature, relative humidity, radian energy, and. Or any conditions or pollutants found in the atmosphere in various geographical areas, which may accelerate changes in properties of materials over those natural weather conditions.
Asbestos – A group of natural fibers impure silicate materials.
Asphalt – A dark brown to black cementitious material in which the predominating constituents are bitumens that occur naturally or are obtained in petroleum processing.
Asphalt, air blown – an asphalt produced by blowing are through molten asphalt at an elevated temperature to raise its softening point and modify other properties.
Asphaltene– a high molecular weight hydrocarbon faction precipitated from asphalt by a designated paraffinic naphtha solvent at a specified temperature and solvent-asphalt ratio.
Asphalt felt – an asphalt saturated felt
Asphaltite – A natural asphalt found below ground level.
Asphalt mastic – a mixture of asphaltic material and graded mineral aggregate that can be poured when heated, but requires mechanical manipulation to apply.
Asphalt rock (rock asphalt) – a naturally occurring rock formation, usually in limestone or sandstone, containing throughout its mass a minor amount of asphalt.
Asphalt roof cement– a trawlable mixture of asphalt solvents, mineral stabilizers, fillers, or fibers, or both.
Asphalt, steam blown – an asphalt produced by blowing steam through molten asphalt to modify its properties
Backnailing – the practice of blind-nailing roofing felts to a substrate in addition to hot-mopping to prevent slippage.
Base ply – the bottom of the first ply in a built-up roofing membrane when additional plies are to be subsequently installed.
Base sheet– a product intended to be used as a base ply in a built-up roofing system
Bitumen – a class of amorphous, black or dark-colored, (solid, semi-solid, or viscous) cementitious substances, natural or manufactured, composed principally of high molecular weight hydrocarbons, soluble in carbon disulfide, and found in asphalts, tars, pitches, and asphaltites: (2) a generic term used to denote any material composed principally of bitumen.
Bituminized – impregnated with bitumen. Example: bituminized fiber pipe
Bituminous emulsion – a suspension of minute globules of bituminous materials in water or an aquatic solution; (2) a suspension of minute globules of water or an aquatic solution in a liquid bituminous material (invert emulsion)
Bituminous group – a mixture of bituminous material and find sand that will flow into place without a mechanical manipulation
Blast-furnace slag – the nonmetallic product, consisting essentially of silicates and alumino-silicates of calcium and other bases, that is developed in a molten condition simultaneously with iron in a blast furnace.
Blind nailing – the use of nails that are not exposed to the weather in the finished roofing
Blister – a raised portions of a roofing membrane resulting from local internal pressure; (2) the similarly formed protuberance in coated prepared roofing.
Blocking – wood built into a roofing system above the deck and below the membrane and flashing to (a) stiffen the deck around an opening (b) act as a stop for insulation, (c) service as a nailer for attachments for the membrane or flashing. (2) wood cross-members installed between rafters or joists to provide support at the cross-joints between deck panels. (3) cohesion or adhesion between similar or dissimilar materials in roll or sheet form that may interfere with the satisfactory and efficient use of the material.
Bond – the adhesive and cohesive forces holding two roofing components in intimate contact.
Brooming – embedding a ply by using a broom to smooth it out and ensure contact with the adhesive under the ply
Built-up roofing – a continuous, semiflexible membrane consisting of plies of saturated felts, coated felts, fabrics, or mats assembled in place with alternate layers of bitumen, and surfaced with mineral aggregate, bituminous materials, or a granular surfaced sheet.
Cant stip – a beveled strip used under flashings to modify the angle at the point where the roofing or waterproofing membrane meets any vertical surface.
Cap sheet – a granule-surfaced coated felt used as the top ply of built-up roofing membrane.
Cationic emulsion – an emulsion in which the emulsifying system establishes a predominance of positive charges on the discontinuous phase.
Caulking – a composition of vehicle and pigments, used at ambient temperatures for filling joints, that remains plastic for an extended time after application.
Coal-tar – a dark brown to black, solid cementitious material produced by the destructive distillation of coal.
Coat tar roof cement – a felt that has been saturated with refined coal tar.
Coal-tar felt – a felt that has been saturated with refined coal tar.
Coal-tar pitch – a dark brown to black, solid cementitious material obtained as residue in the partial evaporation or distillation of coal tar.
Coated sheet (or felt) – and asphalt felt that has been coating on both sides with harder, more viscous ashpahlt; (2) a glass fiber felt that has been simultaneously impregnated and coated with asphalt on both sides.
Cold-process roofing – a continuous, semiflexible membrane consisting of plies of saturated felts, coated felts, fabrics, mats or fabrics laminated on a roof with alternate layers of roof cement and surfaced with a cold-applied coating.
Concealed membrane waterproofing – also referred to as structural slab waterproofing; (1) for below grade: refers to a form of waterproofing where the membrane is applied to the mud mat and later covered with a topping, usually concrete, to act as a wearing layer of course, and (2) for elevated structural concrete deck: applied over the structural surface and covered/concealed by other components such as a topping slab, pavers, ballast, pavement, and plantings.
Condensation– the conversion of water vapor or other gas to liquid as the temperature drops or atmospheric pressure rises.
Conditioning – the storage of a specimen under specified temperature, humidity, ect., for a specified time prior to testing.
Conductance, thermal– thermal transmission in unit time through unit area of a particular body or assembly having defined surfaces, when unit average temperature difference is established between the surfaces.
Conductivity, thermal – the thermal transmission, by conduction only, in unit time thought unit area between two isothermal surfaces of an infinite slap of homogeneous material of units’ thickness, in a direction perpendicular to the surface, when unit temperature difference is established between the surfaces.
Coping – a covering on top of a wall exposed to the weather, usually sloped to carry off water.
Counterflashing – formed metal or elastomeric sheeting secured on or into a wall, curb, pipe, roof-top unit, or other surface, to protect the upper edge of a base flashing and its associated fasteners.
Coverage– the surface area to be continuously covered by a specific quantity of a particular material.
Creep– the time-dependent part of a strain resulting from stress
Cricket – a construction to divert water around or away from a chimney, curb, wall, expansion joint or other penetration.
Crushed stone – the product resulting from the artificial crushing of rocks, boulders, or larger cobble stones, substantially all faces of which have resulted from the crushing operation.
Cutback – solvent-thinned bitumen used in cold-process roofing adhesives, flashing cement, and roof coatings.
Cutoff – a detail designed to prevent lateral water movement into the insulation where the membrane terminated at end of a day s work or used to isolate sections of the roofing system. It is usually removed before the continuation of the work.
Damp proofing – treatment of a surface or structure to resist the passage of water in the absence of hydrostatic pressure.
Dead level – absolutely horizontal , or zero degree
Dead level asphalt– a roofing asphalt conforming to the requirements of Specification D312, Type I
Dead level roofing– a roofing system applied o a surface with a 0% to 2% incline
Deck – the structural surface to which the roofing or water proofing system is applied (including the insulation)
Direction change – a change in the orientation of the principal dimensions or of the support of adjoining units of the roofing system.
Double pour – to apply two layers of aggregate and bitumen to a built-up roof
Dry felt – a felt which has not been saturated with bitumen
Edge stripping– application of felt strips cut to narrower widths than the normal felt roll width to cover a joint between flashing and built-up roofing.
Edge venting– the practice of providing regularly spaced protected openings at a roof perimeter to relieve water vapor in the insulation.
Elastomer– a macromolecular material that returns rapidly to its approximate initial dimensions and shape after substantial deformation by a weak stress and subsequent release of that stress.
Embedment – the process of pressing felt, aggregate, fabric, mat, or panel uniformly and completely into thot bitumen or adhesive to ensure intimate contact at all points: (2) the process of pressing granules into coating in the manufacture of factory prepared roofing, such as shingles.
Emulsion – an intimate mixture of bitumen and water, with uniform dispersion of the bitumen of water globules, usually stabilized by an emulsifying agent or system
Envelope– a continuous membrane edge seal formed at the perimeter and at penetrations by folding the base sheet or ply over the plies above and securing it to the top of the membrane. The envelope prevents bitumen seepage from the edge of the membrane.
Equilibrium moisture content– the moisture content of a material stabilized at a given temperature and relative humidity, expressed as a percent moisture by weight: (2) the typical moisture content of a material in any given geographical area.
Equiviscous temperature (EVT) – the temperature at which a bitumen attains the proper viscosity for built-up membrane application, EVT may or may not be applicable to polymer modified bituminous sheet materials.
Expansion Joint– a structural dimension between two building elements that allows free movement between two building elements without damage to the roofing or waterproofing systems.
Exposure – the transverse dimension of a roofing element not overlapped by an adjacent element in any roofing system. The exposure of any ply in a membrane may be computed by dividing the felt width of minus 51 mm (2 in.), by the number of shingled plies: thus, the exposure of a 914 mm (36 in) wide felt in a shingled, four-ply membrane should be 216 mm (8 ½ in); (2) the time during which a portion of a roofing element is exposed to the weather.
Facer – the outermost, adhered top or bottom, or both, sheet (or layer) of an insultation board that is comprised of a different material that the insulation itself. It is commonly composed of organic paper, glass mat, or both, with asphalt, latex, or the like: or metal foil.
Fallback – a reduction in bitumen softening point, sometimes caused by refluxing or overheating in a relatively closed container.
Felt – a flexible sheet manufactured by the interlocking of fibers with a binder or through a combination of mechanical work, moisture, and heat. Felts are manufactured principally from vegetative fibers, asbestos fibers, or glass fibers; other fibers may be present in each type.
Felt layer – a machine used for applying bitumen and built-up roofing felts
Felt mill ream – the mass in pounds of 480 Ft2 of dry, unsaturated felt, also termed “point weight”
Finger Blisters – finger shaped blisters or wrinkles in the plies of a built-up roofing or waterproofing membrane.
Fishmouth – a half-cylindrical or half-conical opening formed by an edge wrinkle or failure to embed a roofing felt; (2) in shingles, a half-conical opening formed at the cut edge.
Flashing – the system used to seal membrane edges at walls, expansion joints, drains, gravel stops, and other places where the membrane is interrupted or terminated. Base flashing covers the edged of the membrane. Cap or counterflashing shields the upper edges of the base flashing.
Flashing cement – a trowelable mixture of cutback bitumen and mineral stabilizers including asbestos and other inorganic fibers.
Flash asphalt – a roofing asphalt conforming to the requirements of Specification D312, Type II
Flood coat– the top layer of bitumen used to hold the aggregate on an aggregate-surfaced, built-up roofing membrane.
Fluid-applied elastomer – an elastomeric material, fluid at ambient temperature, that dies or cures after application to form continuous membrane. Such systems normally do not incorporate reinforcement.
Flux – a bituminous material used as a feed back stock for further processing and as a material to soften other bituminous materials.
“free carbon” in tars – the hydrocarbon fraction that is precipitated from a tar by dilution with carbon disulfide.
Glass felt– glass fibers bonded into a sheet with resin and suitable for impregnation in the manufacture of bituminous waterproofing, roofing membranes, and shingles.
Glass mat – a think mat of glass fibers with or without binders.
Glaze coat – (1) the top layer of asphalt in a smooth-surfaced built-up roof assembly (2) a thin protective coating bitumen applied to the lower plies or top ply of a built-up membrane, when application of additional felts, or the flood coat and aggregate are delayed.
Gravel – coarse, granular aggregate, with pieces larger than sand grains, resulting from the natural erosion of rock.
Gravel Stop – a flanged device, frequently metallic, designed to prevent loose aggregate from washing off the roof and to provide continuous finished edge for the roofing.
Headlap – in roofing, for products installed in a shingle fashion, the area on the shingle or the sheet material that is covered by the requisite number of layers in multiply construction; for example, two layers on a strip shingle or three layers in a three-ply built-up roof. Headlap is commonly referred to by its width, thus the designation by linear dimension.
Heat exposure – the process of subjecting a specimen to an elevated temperature at atmospheric pressure for a specified period of time with the intent of determining properties by subsequent testing.
Holiday – an area where a liquid-applied material is missing
Hydrokinetic roof system – a roof system that depends on quick drainage via water shedding to prevent water entry into or through the system
Hydrostatic roof system – a roofing system that is capable of holding water without allowing water to penetrate the system.
Hygroscopic – attracting, absorbing, and retaining atmospheric moisture.
Impregnate – in roofing materials manufacture, to completely surround the fibers in a felt or mat with bitumen, with the spaces between the fibers partially or completely filled without a continuous coating of bitumen on the surface.
Incline – the slope of a roof expressed in percent or in the number of vertical units of rise per horizontal unity of run.
Inorganic – being or composed of matter other than hydrocarbons and their derivatives, or matter that is not of plant or animal origin.
Knot – an imperfection or nonhomogeneity in materials used in fabric construction, the presence of which causes surface irregularities.
Loose-laid membrane – a ballasted roofing membrane that is attached to the substrate only at the edges and penetrations through the roof.
Lot – in roofing (1) production lot – all material produced in one eight-hour shift of the same type (and color when applicable) (2) delivery lot – all material of the same type delivered at one time by one truck or railroad car.