Liter

A layer of weak, nondurable material containing cement and fines from aggregates, brought by bleeding water to the top of overwet concrete. Laitance may be detected by scraping the concrete surface with a putty knife; if a quantity of loose powdery material is observed or easily removed, excessive laitance may be considered to be present.

Strip shingles containing more than one layer of tabs to create extra thickness. Also called three-dimensional shingles or architectural shingles.

(1) The process of joining thin layers of material together under heat and pressure (with an adhesive) into a finished product; (2) To bond two or more layers of a material together to make a finished product.

(1) The part of a roofing membrane that covers the preceding course in any overlapping situation; (2) Dimension by which a felt covers an underlying felt in a multi-ply built-up bituminous membrane. Edge lap indicates the transverse cover; end lap indicates the cover at the end of the roll. These terms also apply to single-ply membranes; (3) To cover the surface of one shingles or roll with another. Low Slope Application – Method of installing asphalt shingles on roof slopes between 2 and 4 inches apart; (4) That part of a roofing, waterproofing or flashing component that overlaps or covers any portion of the same or another type of adjacent component.

Occurs where overlapping materials are seamed, sealed or otherwise bonded.

A soft workable metal used for miscellaneous flashings.

See CONDUCTOR HEAD.

Pounds

A method of economic analysis that takes into account expected costs over the useful life of an asset.

The percentage of light that is not absorbed by the surface of a material.

(1) Moving of non-permanent loads such as winds, snow, ice, rain, portable equipment, or roof installation equipment; (2) Temporary loads that the roof structure must be designed to support, as required by governing building codes. Live loads are generally moving and/or dynamic or environmental (e.g., people, installation equipment, wind, snow, ice or rain, etc.).

Membranes that are not attached to the substrate except at the perimeter of the roof and at penetrations. Typically, loose-laid membranes are held in place with ballast, such as water worn stone, gravel, pavers, etc.

Design concept in which insulation boards and membrane are not anchored to the deck but ballasted by loose aggregate or concrete pavers.

The ability of the membrane to remain flexible and not embrittle at low temperatures.

(1) The lowest temperature at which a material can withstand a bending test around a mandrel of specified shape; (2) The ability of a membrane or other material to remain flexible (resist cracking when flexed), after it has been cooled to a low temperature.