National Association of Home Builders

(1) Wood member bolted or otherwise anchored to a nonnailable deck or wall to provide nailing anchorage of membrane roof felts or flashings; (2) A piece or pieces of dimensional lumber and/or plywood secured to the structural deck or walls, which provide a receiving medium for the fasteners used to attach membrane or flashing. Generally, it is recommended that nailers be the same thickness as the adjacent insulation, and may be treated with a non-oil borne preservative, and be of sufficient width to fully support the horizontal flashing flange of a metal flashing (where used).

(1) In the Exposed Nail Method, nail heads are exposed to the weather; (2) in the Concealed Nail Method, nail heads are concealed from the weather; (3) Exposed nailing of roofing wherein nail heads are exposed to the weather; (4) Concealed nailing of roofing wherein nail heads are concealed from the weather by an overlapping material. See also BLIND NAILING.

Acrylonitrile butadiene polymer blend. One proprietary NBP membrane is commonly referred to as Nitrile butadiene copolymer.

A fabric where barbed needles (in multiple punches) achieve mechanical bonding or interlocking of fibers.

A synthetic rubber (chemically polychloroprene) used in liquid applied and sheet-applied elastomeric single-ply roof membranes or flashings. See POLYCHLOROPRENE.

National Emission Standards for Hazardous Air Pollutants

A method of reroofing with new asphalt shingles over old shingles in which the top edge of the new shingle is butted against the bottom edge of the existing shingle tab.

The area, measured in square inches, open to "unrestricted' air flow and commonly used as a "yardstick" to measure relative vent performance.

SI unit of measure for force.

Nanogram

National Insulation Contractors Association

A material and/or method used to temporarily seal a membrane edge during construction to protect the roofing assembly in place from water penetration. Usually removed when roofing application is resumed.

("Double-Coverage or Split-Sheet") A prepared roofing sheet with a 17" (430mm) granule surfaced exposure and a nongranule-surfaced 19" (485mm) selvage edge. This material is sometimes referred to as SIS, double-coverage or according to ASTM Standard D 371 89, Standard Specification for Asphalt Roll Roofing (Organic Felt) Surfaced with Mineral Granules, Wide Selvage. See SPLIT SHEET.

A prepared organic felt roll roofing with a granule surfaced exposure that has a mass of approximately 90 pounds per 100 square feet (4400 g/m2).

National Institute of Occupational Safety & Health

National Institute of Standards and Technology

An elastomeric material of synthetic non-vulcanizing polymers.

A membrane whose predominant resinous ingredient is a synthetic rubber made by the polymerization of acrylonitrile with butadiene.

Shingles consisting of a single solid tab with not cutouts.

A method to evaluate the disposition, strength or composition of materials without damaging the object under test. Typically used to evaluate moisture content in roofing assemblies, the three common test methods are electrical capacitance, infrared thermography, and nuclear back-scatter.

A membrane manufactured from thermoplastic compounds that retains its thermoplastic properties throughout the service life of the membrane.

(1) A term used to describe fabrics, mats or scrims that are produced using processes other than weaving or knitting. Many nonwoven processes (i.e., spunbonded or wet laid, etc.) produce a random arrangement of reinforcing fibers (glass, polyester, etc.) in a mat or fabric; (2) The arrangement of reinforcing fibers (glass, polyester, etc.) in a mat. Fibers may be in a random pattern, jack straw or some other form; not a woven fabric.

Method of installing asphalt shingles on roof slopes between 4" and 21" per foot.

National Roofing Contractors Association, Chicago, IL

National Tile Roofing Manufacturers Association

A device that contains a radioactive source to emit high velocity neutrons into a roof system. Reflecting neutrons are measured by a gauge that is used to detect moisture.

Generic name for a family of polyamide polymers, used as a scrim in some fabric reinforced sheeting.