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Aggregate The standard term for any granular mineral material used for surfacing a built-up roof – crushed stone, crushed slag or water worn gravel. Asphalt A brownish-black solid or semisolid mixture of bitumens obtained from native deposits or as a petroleum byproduct, used in paving, roofing and waterproofing. Often applied to various papers, felts, and sealant products for waterproofing. Bitumen Any of various flammable mixtures of hydrocarbons and other substances, occurring naturally or obtained by distillation from coal or petroleum, that are a component of asphalt and tar and are used for waterproofing. Found in petroleum asphalts, coal tars and pitches, wood tars and asphalts. BTU (British Thermal Unit) A rate of measurement for insulation material. The term represents the amount of heat required to increase the temperature of one pound of water one degree F. Built-up Roof Membrane (BUR) A continuous, semi-flexible, multi-ply roof membrane, consisting of layers of felt, fabrics or mats. Catalyst A substance, usually used in small amounts relative to the reactants, that modifies and increases the rate of a reaction without being consumed in the process. Contract The written form of an agreement, enforceable by law, between two or more people. Contractor A trained professional who agrees to furnish materials or perform services at a specified price. *Only hire contractors who carry contractors’ licenses. Cure To prepare, preserve or finish (a substance) by a chemical or physical process, including heat, pressure and weathering. Dry Rot A fungous disease that causes timber to become brittle and crumble into powder. Eichler Colloquial expression for the elegant, modern, moderately priced (when originally built!) homes conceived and built by the pioneering developer of residential suburbs in the 1950s and sixties, Joseph Eichler. Elastomeric Top Coat A high-performance 100% acrylic foam roof coating that eliminates UV attack. The coating must be applied within 72 hours after application of the foam roofing insulation. Flashing A self-adhesive, protective system designed for foam roofing systems to seal edges at walls, expansion joints, drains, gravel stops and other places where the roofing material is interrupted or terminated. Granule This opaque, natural or synthetically colored aggregate is used for foam roofing systems as a final protective coating. Gravel A natural material applied to tar and gravel roofs. This coarse, granular aggregate contains small pieces approximately 5/8 inch to 1/2 inch in size. Insulation The material or substance used to insulate against heat, cold, sound, etc. Moisture Vapor Transmission The rate of movement of moisture vapor in unit time through a unit area of a membrane. Ply The term used to describe a layer of felt in a foam roofing (built-up roof membrane) system. For example, a four-ply membrane system has four plies felt. Plywood A structural material made of layers of wood glued together, usually with the grains of adjoining layers at right angles to each other. Polyurethane Spray Foam Polyurethane foam is a rigid closed cell plastic created by a combination of two liquid components which react in seconds and can be walked on in a matter of minutes. Polyurethane foam stops leaks and ponding water and insulates – creating a lightweight, seamless, waterproof “blanket” over the structure. Ponding The term used to describe a pool of water at least 1/2" deep that remains in an area at least 100 square feet for one full day (24 hours) after a rain. “R” Factor The formula for determining thermal resistance. Each roof or wall material has a pre-calculated resistance value which, when added together, represents the composite system’s total resistance to heat flow. Seamless Polyurethane foam is applied as a liquid, creating a single monolithic membrane that covers the entire roof. There are no seams or joints – the source of the majority of leaks in traditional roofs. Slope This is the angle of the roof that is often called the “fall area.” Most roofs built in the 1960's, 70's and 80's were built with 4/12 to 6/12 roof slopes. Slope - Low Indicates a roof slope of 1/2 inch per foot to 1/2 inch per foot. SPF An acronym for “Sprayed Polyurethane Foam” – This sophisticated, rigid, leak and weather resistant material is used for foam roofing systems and as an excellent insulation. Substrate The material or surface (wood, metal, concrete, etc.) to which the roofing or waterproofing membrane is applied. Tar A heavy, dark, oily, viscous material, consisting mainly of hydrocarbons, produced by the destructive distillation of organic substances such as wood, coal or peat. No insulation value. Thermal Conductance (C) A specific unit of heat flow that is used to determine the specific thickness of material or for materials of combination construction, such as laminated insulation. Thermal Conductivity (k) A unit for comparing or calculating quantities of heat. Thermal Conductivity is the amount of heat necessary to raise the temperature of one gram or one pound of water from zero to one degree Centigrade. Thermal Resistance (R) The index of a material's resistance to heat flow; it is the reciprocal of thermal conductivity (k) or thermal conductance (C). Thermal Shock Represents severe stress on and/or changes in a roof membrane resulting from sudden fluctuations in temperature (i.e.: a pelting rain storm followed by intense sunshine.) Thermoplastic Olefin Membrane (TPO) A proprietary blend of polypropylene and ethylene-propylene polymers. Tongue & Groove Interlocking wooden boards with a groove on one side and a ridge or tongue on the other. Traffic Bearing Membrane A membrane tested and formulated to withstand a predetermined amount of use. |
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