Z-Channel 
Flashing, shaped in the form of a Z, which is used along a horizontal edge between abutting vertical exterior wall panels. Any water that seeps into the joint is then directed outward by gravity to the outside of the wall. 

Z Flashing 
Galvanized steel, aluminum or plastic, in the shape of a Z, which prevents water penetration when installed at horizontal joints. 

Z-Frame Gate 
A diagonal cross support in the shape of a Z is used for the main structure of this type of sturdy gate. 

Z-Tie 
Metal tie used to unite masonry walls. 

Zero Clearance 
The lack of a need for a specified distance between a well-insulated heating unit or metal wood burning fireplace and a combustible surface. 

Zero Line 
The point in earthmoving where an imaginary line denotes a place where no cutting or filling is required. 

Zero Lot Line 
Lot where a home is set to the lot boundary, which leaves very little space between the houses. 

Zero Rate Loan 
Loan with large down payment and the balance being paid in equal periodic payments over a short period of time, with no interest charged. Usually offered by an eager seller. 

Zero Net 
When there is no money left for the seller, from the sale of a property, after all outstanding expenses are paid. 

Zigzag Fence 
Laid out in a zigzag pattern, with split rails intersecting and supporting each other and anchored with spikes at the joint, this type of fence is also referred to as a snake fence. 

Zinc 
Often used for galvanizing or coating steel, this white metallic element with the atomic symbol Zn, atomic number 30 and atomic weight of 65.37, it inhibits corrosion and oxidation.

Zinc Chromate 
Protective undercoat for metal, a yellow primer and corrosion inhibitor. 

Zinc Oxide 
White compound is both an ingredient in pharmaceuticals and cosmetics as well as a paint pigment. 

Zinc Sulfide 
Compound used as a white pigment and a phosphor it is fluorescent white to yellow. 

Zinc Yellow 
Protective undercoat for metal, a yellow primer and corrosion inhibitor. 

Zip Cord 
Also known as sp wire or lamp cord, these small diameter stranded wires are covered with rubber insulation. 

Zip Strip 
T-shaped vinyl strips used to form expansion joints in concrete slabs are inserted into the concrete immediately after finishing. Once the concrete is set, the top strip is peeled away to expose the concealed joint. 

Zonal Cavity Lighting 
The calculation of the amount of light needed in a room done by dividing the room into zones and determining the needs of each particular area. The Illumination Engineering Society has advised the lighting requirements of each zone: the ceiling cavity, the room cavity and the floor cavity. 

Zone 
Geographic location with designated boundaries such as a district. 

Zone, HVAC 
Heating and air conditioning systems that heat or cool various parts of a building with separate and adjustable controls. 

Zone Representative 
Person, such as an elected official, who represents a zone. 

Zone Switching 
Lights operated by electrical switches in a section (zone) of a room. 

Zoning 
Rules and regulations controlling the use of land, which is broken down into districts and determines how private property is to be used or what construction is allowed. Zoning may be either commercial, residential, industrial or agricultural. Zoning also restricts height limitations, noise, parking, open space. Residential zoning may consist of single-family, two family or apartments. 

Zoning Board of Appeals 
Local government board, which is used to resolve zoning disputes. 

Zoning Laws 
Ordinances created by local government to cover real estate development, including structural and esthetic points. They usually define usage classifications from agricultural to industry and also building restrictions such as minimum and maximum square footage requirements and violations penalties and procedures. 

Zoning Map 
Map that shows locality divided into districts and shows status and usage of each district and is kept current. 

Zoning Ordinances 
Regulations determined by each municipality to establish different zoning restrictions and classifications, for example building height, type of buildings, etc. Penalties are assessed for violation of zoning ordinances. In some instances, variations to zoning ordinances are allowed and are called variances. 

Zoning Records 
Compilation of zoning requirements and any changes made to them. 

Zoning Variance 
A modification of the existing zoning law, which can be made in certain instances, for example to build a taller building than allowed or a different type of housing than that which is allowed. 

Zonolite 
Used as both an aggregate in the making of insulating concrete and as loose-fill insulation, it's a lightweight insulating material.