An inspection made by a municipal building inspector after the drywall material is hung with nails and screws (and before taping).

Fibers found in nature, such as wool and cotton.

The loosening of nails holding gypsum board to a wall or ceiling. It produces a bulge in the surface of the gypsum panel.

A substance intentionally engineered to achieve size-dependent properties and functions with one or more external dimensions or an internal structure measuring less than 100 nanometers. https://healthymaterialslab.org/tool-guides/hml-resources

The protrusion of the nail usually attributed to the shrinkage of or use of improperly cured wood framing.

National Conference of States on Building Codes and Standards, a nonprofit organization formed to increase interstate cooperation and coordinate intergovernmental reforms of building codes.

National Bureau of Standards, a federal agency.

A gypsum plaster with no aggregates or fillers added. Sometimes called unfibered gypsum.

A steel or wood beam that is run through an opening in a bearing wall and used to support the wall and related loads as work on the foundation below the wall is performed.

National Board of Fire Underwriters, now merged into the American Insurance Assn.

A set of rules governing safe wiring methods. Local codes—which are backed by law—may differ from the NEC in some ways.

A transparent finish which does not seriously alter the original color or grain of the natural wood. Natural finishes are usually provided by sealers, oils, varnishes, water repellent preservatives, and other similar materials.

A substance that can damage the central nervous system. https://healthymaterialslab.org/tool-guides/hml-resources

Usually color-coded white, this carries electricity from an outlet back to the service panel. Also see hot wire and ground.

The plane through a member (at the geometric center of the section in symmetrical members) where the fibers are neither under tensile nor compressive stress.

A single number indicated by the amount of airborne sound energy absorbed into a material. The arithmetic average of sound absorption coefficients at 250, 500, 1000 and 2000 Hz.

NAUF certifies that products have no added urea formaldehyde. As of 2018, this certification is no longer recognized as an exemption to CARB or TSCA Title VI regulations. https://healthymaterialslab.org/tool-guides/hml-resources

The NAF standard for No Added Formaldehyde is currently the highest federal standard regulating formaldehyde emissions. NAF certifies that composite wood is free of resins made from urea formaldehyde or phenol formaldehyde, which have the potential to off-gas after installation and are known carcinogens. NAF certification originated with CARB, and has since been adopted by the EPA for the TSCA Title VI regulation. https://healthymaterialslab.org/tool-guides/hml-resources

National Forest Products Association.

National Fire Protection Assn., an international technical society that disseminates fire prevention, fighting and protection information. NFiPA technical standards include the National Electrical Code which is widely adopted.