Overall coefficient of thermal transmission.

Uniform Building Code

Underwriters Laboratories, Inc.

An identification label or seal affixed to a roofing product or package with the authorization of Underwriters Laboratories, Inc. The presence of the label indicates that the product has met certain performance criteria.

The amount a material stretches during tensile testing before it ruptures. Usually expressed as a percentage of the original length.

(1) Situated beyond the visible spectrum, just beyond the violet end, having wavelengths shorter than wavelengths of visible light and longer than those of X-rays; (2) relating to, producing or employing ultraviolet radiation.

(1) An asphalt-saturated felt or other sheet material (may be self adhering) installed between the roof deck and the roof system, usually used in a steep-slope roof construction. Underlayment is primarily used to separate the roof covering from the roof deck, to shed water, and to provide secondary weather protection for the roof area of the building; (2) One or more layers of felt, sheathing paper, nonbituminous saturated felt, or other approved material over which a steep-slope roof covering is applied.

(1) An organization that classifies roof assemblies for their fire characteristics and wind uplift resistance for insurance companies in the United States; a nationally recognized fire and safety related testing facility; (2) An organization that tests, rates and classifies roof assemblies for their resistance to fire, impact, leakage, corrosion of metal components and wind uplift.

Label displayed on packaging to indicate the level of fire and/or wind resistance of asphalt roofing

The maximum extension of the material at the moment of rupture.

Micrometer

The state of a material (thermoplastic) before it is subjected to curing.

Asphalt saturated felt used beneath roofing to provide additional protection for the deck.

See WIND UPLIFT.

The ability of a material to resist breakdown due to ultraviolet exposure.