UL (Underwriters' Laboratories) - An independent testing agency that checks electrical devices and other components for possible safety hazards.
Undercoat- 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.
Underground Plumbing - The plumbing drain and waste lines that are installed beneath a basement floor.
Underlayment- A ΒΌ" material placed over the sub-floor 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.
Underpinning the Foundation Walls - In this method, sequences of holes are dug-out from under the footing of your home. (The footing is the concrete or brick pad, which spreads the load of the foundation walls onto the soil.) Typically, a series of 4' wide holes, separated by 8' of undisturbed soil, is prepared and filled with concrete. The top 2" of the concrete filled hole is packed with non-shrink grout, rather than filled to the top with concrete, so as to avoid the possibility that air pockets are present. Once the first series of holes are filled with concrete, the adjacent 4' wide segment is dug-out, and the underpinning process continues. Here, the idea is that you extend the footing of the house to a lower level, which then permits you to dig-out the soil from the inside of the basement, without undermining the foundation walls of the house.
Union - A plumbing fitting that joins pipes end-to-end so they can be dismantled.
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.