nailer: A piece of lumber secured to non-nailable decks and walls by bolts or other means, providing a suitable backing onto which roof components may be mechanically fastened.
natural finish: A transparent finish that does not significantly alter the original color or grain of the natural wood. A natural finish is typically achieved using sealers, oils, varnishes, water-repellent preservatives, and other similar materials.
neat plaster: A base coat plaster that does not contain aggregates and is used where the addition of aggregates on the job is desired.
NEC (National Electrical Code): A set of rules governing safe wiring methods. Local codes that are backed by law may differ from some codes in the NEC.
neoprene: A synthetic rubber having physical properties that closely resemble those of natural rubber, and used in weather-resistant products, such as paints, adhesives, gaskets, etc. It is made by polymerizing chloroprenes, which are produced from acetylene and hydrogen chloride.
nesting: A method of re-roofing with new asphalt shingles over old shingles in which the top edge of the new shingles is butted against the bottom edge of the existing shingle tab.
neutral wire: Carries electricity from an outlet back to the service panel; usually color-coded white. See also hot wire and ground.
newel: Any post to which the end of a stair railing or balustrade is fastened.
NFPA: National Fire Protection Association, which sets standards for fire-rated building products.
nipple: A short pipe coupling that is threaded on both ends and installed between fittings.
NM (non-metallic): A flame-retardant type of Romex cable, which is a non-metallic sheathed cable that contains several conductors. Its use is limited to dry locations.
NMC (non-metallic conduit): A type of Romex® cable, which is a non-metallic sheathed cable that contains several conductors. NMC may be used in damp or corrosive locations, as well as dry areas.
no-cutout shingles: Shingles consisting of a single solid tab with no cutouts.
nominal size: Size used for identification only; not literal dimensions.
non-bearing wall: A wall supporting no load other than its own weight.
non-combustible: A substance that does not burn when subjected to fire.
non-destructive: Describes a method of examining the interior of a component whereby no damage is done to the component itself.
non-drying: A sealant that does not set up or cure. See also butyl. Also called non-curing.
non-fibered aluminum roof coating: Thin but efficient barrier that reflects the sun's harmful rays and prolongs a roof surface's service life. Also used on other metal surfaces.
non-fibered roof and foundation coating: Dual-purpose, thin-viscosity material that doubles as a non-fibered roof and foundation coating.
non-sag: A sealant formulation having a consistency that permits application in vertical joints without appreciable sagging or slumping.
non-skinning: Descriptive of a product that does not form a surface skin.
non-staining: Characteristic of a compound that will not stain a surface.
non-veneer panel: Any wood-based panel that does not contain veneer and carries an APA span rating, such as waferboard and oriented strand board.
normal operating controls: The operating controls for devices that can be operated by ordinary occupants, such as thermostats, as they require no specialized skill, knowledge or tools.
normal slope application: Method of installing asphalt shingles on roof slopes between 4 inches and 21 inches per foot.
nosing: The projecting edge of a molding or drip usually applied to the projecting molding on the edge of a stair tread.
notch: A crosswise rabbet at the end of a board.
note: A formal document showing the existence of a debt and stating the terms of repayment.
nozzle: The tubular tip of a caulking gun through which the compound is extruded.
nuclear meter: A device used to detect moisture by measuring slowed, deflected neutrons.