An independent testing agency that checks electrical devices and other components for possible safety hazards.

University of California, an independent fire-testing laboratory.

Underwriters Laboratories Inc., founded by NBFU, and now operated in affiliation with American Insurance Assn. UL is a not for profit laboratory operated for the purpose of testing devices, systems and materials as to their relation to life, fire and casualty hazard in the interest of public safety.

Uniform Building Code - document promulgated by the International Conference of Building Officials.

Coefficient of heat transfer, "U" equals 1 divided by (hence, the reciprocal of) the total of the resistances of the various materials, air spaces and surface air films in an assembly. See Thermal Resistance.

The maximum stress, such as tensile, compressive, or shear, that a material can withstand.

A method of non-destructive testing of materials that uses high frequency sound vibrations to find defects in the material.

Products with a ULEF certification have ultra-low emitting formaldehyde resins which have been shown to have formaldehyde emissions below the limits established by CARB Phase 2. The ULEF 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

The maximum tensile stress of a material up to the point of rupture.

A plumbing fitting that joins pipes end-to-end so they can be dismantled.

A neat gypsum. It has no additives.

A coating applied prior to the finishing or top coats of a paint job. It may be the first of two or the second of three coats. Sometimes called the Prime coat.

Concrete placed without steel-reinforcing bars or welded-wire fabric.

Sheet material, such as hardboard, that is laid over the subfloor to provide a smooth, stiff surface for the finish flooring.

A ¼" material placed over the subfloor plywood sheeting and under finish coverings, such as vinyl flooring, to provide a smooth, even surface. Also a secondary roofing layer that is waterproof or water-resistant, installed on the roof deck and beneath shingles or other roof-finishing layer.

The plumbing drain and waste lines that are installed beneath a basement floor.

Any load that is spread out evenly over a large area.

A flat, insulated electric wire that is run under the carpet.

Placing a new foundation below the existing foundation.

The area of the earth that has electric, gas, or telephone lines. These areas may be owned by the homeowner, but the utility company has the legal right to enter the area as necessary to repair or service the lines.