Roofing Glossary: A to D

the ability to resist being worn away by contact with another moving, abrasive surface, such as foot traffic, mechanical equipment, wind-blown particles, etc.

Shrinkage cracking of the surfacing bitumen on a built-up roof, producing a pattern similar to an alligator’s hide. The cracks may or may not extend through the entire surfacing bitumen thickness.

A blend of two or more polymers, e.g., a rubber and a plastic to improve a given property, e.g., impact strength.

a group of natural, fibrous, impure silicate materials.

a dark brown or black substance found in a natural state or, more commonly, left as a residue after evaporating or otherwise processing crude oil or petroleum. Asphalt may be further refined to conform to various roofing grade specifications

blind (i.e., concealed by overlapping felt) nailing of roofing felts to a substrate in addition to hot-mopping to prevent slippage.

a material, such as aggregate or precast concrete pavers, which employs impermeable layers of felt or membrane, or between the membrane and substrate designed to prevent wind uplift or flotation of a loose-laid roof system.

A saturated or coated felt placed as the first ply in a multi-ply bituminous roofing membrane.

Raised rib, in a metal roof, or a separate part or formed portion in a metal roofing panel.

A scale in which the force of the wind is indicated by numbers from 0 to 12. No.7 is “near gale” at 52-61 km/h (32-38 m.p.h.). No. 9 is “strong gale” at 76-87 km/h (47-54 m.p.h.).

A suspension of minute globules of bituminous material in water or in an aqueous solution.

Fiberglass insulation in roll form, often installed between metal roof panels and the supporting purlins.

An enclosed pocket of air-water vapor, trapped between membrane plies or between membrane and substrate.

Undesirable rounded delamination of the surface of a polyurethane foam whose boundaries may be either more or less sharply defined.

the adhesive and cohesive forces holding two roofing components in intimate contact.

Airborne burning embers released from a fire.

an upward, elongated displacement of a roof membrane frequently occurring over insulation or deck joints. A buckle may be an indication of movement within the roof assembly.

The minimum construction requirements established generally by national organizations of experts and adopted completely or in altered form by local governing authorities.

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 material, or a granule surfaced sheet (abbreviation, BUR).

Roofer’s term for flashing or plastic cement.

an individual package of shakes or shingles.

The lower edge of the shingle tabs.

a rubber like material produced by copolymerizing isobutylene with a small amount of isoprene, Butyl may be manufactured in sheets, or blended with other elastomeric materials to make sealants and adhesives.

Any overhanging or projecting roof structure with the extreme end usually unsupported.

A beveled strip used under flashings to modify the angle at the point where the roofing or waterproofing membrane meets any vertical element.

A granule-surfaced coated felt used as the top ply of a built-up roofing membrane.

a composition of vehicle and pigment used at ambient temperatures for filling/sealing joints or junctures, that remains elastic for an extended period of time after application.

a line made on the roof or other flat surface by snapping a taut string or cord dusted with colored chalk.

a material used as the exterior wall enclosure of a building.

a continuous metal strip, or angled piece, used to secure metal components.

A non-continuous metal component or angle piece used to secure two or more metal components together.

A resilient strip such as neoprene, flat on one side and formed to the contour of ribbed sheets on the other, used to close openings created by joining metal sheets and flashings.

a layer of liquid material applied to a surface for protection or appearance.

A continuous, semi-flexible roof membrane, consisting of plies of felts, mats, or fabrics that are laminated on a roof with alternate layers of cold-applied roof cement and surfaced with a cold-applied coating.

Pre-formed flange placed over a vent pipe to seal the roof around the vent pipe opening. Also called a vent sleeve.

the conversion of water vapor or other gas to liquid as the temperature drops or the atmospheric pressure rises.

A covering on top of a wall exposed to the weather, usually sloped to carry off water.

the decorative horizontal molding or projected roof overhang.

formed metal or elastomeric sheeting secured on or into a wall, curb, pipe, rooftop unit or other surface, to cover and protect the upper edge of a base flashing and its associated fasteners.

the surface area uniformly covered by a specific quantity of a particular material at a specific thickness.

a nonlinear separation or fracture occurring in a material.

a relatively small area of a roof constructed to divert water from a horizontal intersection of the roof with a chimney, wall, expansion joint or other projection.

a raised member used to support roof penetrations, such as skylights, mechanical equipment, hatches, etc.

BUR membrane defect characterized by a continuous, open longitudinal seal with top felt rolled back from underlying felt.

Solvent-thinned bitumen used in cold process roofing adhesives, flashing cements, and roof coatings.

A detail designed to prevent lateral water movement into the insulation where the membrane terminates at the end of a day’s work, or used to isolate sections of the roofing system, usually removed before the continuation of the work.

treatment of a surface or structure to resist the passage of water in the absence of hydrostatic pressure.

the weight of a structure itself, including the weight of fixtures or equipment permanently attached to it.

a structural component of the roof of a building. The deck must be capable of safely supporting the design dead and live loads, including the weight of the roof systems, and the additional live loads required by the governing building codes and provide the substrate to which the roofing or waterproofing system is applied the structural surface of a building to which a roof assembly is installed. Decks are either non-combustible (e.g., corrugated metal, concrete, or gypsum) or combustible (e.g., wood plank or plywood).

a deleterious change in the chemical structure, physical properties or appearance of a material from natural or artificial exposure (e.g., exposure to radiation, moisture, heat, freezing, wind, ozone, oxygen, etc.).

separation of the laminated layers of a component or system.

The maximum thickness of a roof system upon which a given moisture survey method is effective.

a structure projecting from a sloping roof usually housing a window or ventilating louver.

Doubling of flood-coat, gravelingin operation, to provide additional waterproofing integrity for a BUR membrane.

a vertical pipe or conduit used to carry runoff water from a scupper, conductor head or gutter of a building to a lower roof level or to the ground or storm water runoff system.

an outlet or other device used to collect and direct the flow of runoff water from a roof area.

a metal flashing or other overhanging component with an outward projecting lower edge, intended to control the direction of dripping water and help protect underlying building

A boardwalk or slatted flooring laid on a wet, muddy or cold surface