Last updated July 29, 2026
U-Value
Thermal Transmission; the measurement of the heat loss per square metre from indoors to outdoors for various types of glass or glazing when the difference between the temperature of the air on two sides is one degree. (Refer R-Values).
UNO
Acronym for Unless Noted Otherwise.
Unacceptable Workmanship
Determined not satisfactory by the reviewing authority associated with the contract.
Underlayment
A 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.
Unglazed
Window supplied ex factory without glass.
Unit of Measurement
The basis for uniformly quantifying units of material, work and effort either separately or in combination.
Unplasticised Polyvinyl Chloride
(uPVC) A type of plastic.
Urban
Pertaining to a city or town.
Usable Floor Area
See Area
User
Person, animal or object that a building is designed to accommodate.
Utility Easement
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.
Uv Elimination
The percentage of Ultraviolet Light eliminated by the particular glass type as measured over the 300-380-400 manometer wavelength range.