Z-bar Flashing: Bent, galvanized metal flashing that's installed above a horizontal trim board of an exterior window, door, or brick run. It prevents water from getting behind the trim/brick and into the home.

Zone: The section of a building that is served by one heating or cooling loop because it has noticeably distinct heating or cooling needs. Also, the section of property that will be watered from a lawn sprinkler system.

Zone Valve: A device, usually placed near the heater or cooler, which controls the flow of water or steam to parts of the building; it is controlled by a zone thermostat.

Zoning: A governmental process and specification which limits the use of a property, e.g. single family use, high rise residential use, industrial use, etc. Zoning laws may limit where you can locate a structure. Also see Building Codes.