ABS pipe - Black plastic pipe sometimes used as drainage pipe in plumbing systems.
Absorptivity - a number that indicates what fraction of sunlight falling on a material is absorbed by the material.
Active Solar - A system that uses pumps or fans to move solar energy from the pint of capture (in the collectors) to the living space or to a storage component.
Air space - The area between insulation facing and interior of exterior wall coverings. For best results, manufacturers recommend filling this space with insulation and allowing at least 3/4" air space in installing reflective faced insulation.
Airstat - A regulator that controls the operating temperature of the warm air distribution system in furnaces.
Allowance(s) - a sum of money set aside in the construction contract for items which have not been selected and specified in the construction contract. Best kept to a minimum number and used for items who's choice will not impact earlier stages of the construction. For example, selection of tile as flooring may require an alternative framing or underlayment material.
Amp - A measure of the amount of electrical current going through a circuit at any given time. Also see volt and watt.
Anchor bolts - 'L' shaped bolts which are set in the concrete foundation and used to attach the framing of the house to the foundation (see diagram).
Anemometer - A device that measures wind velocity.
Anticipator - A control subsystem on a thermostat which operates pumps, fans and fuel burner independently of one another.
Aquastat - A regular that controls the operating temperature of the hot water distribution system in boilers and water heaters.
Architect - One who has completed a course of study in building and design, served an internship and passed a test and is licensed by the state as an architect.
Asbestos - A common form of magnesium silicate which was used in various construction products due to it's stability and resistance to fire. Asbestos exposure by inhaling loose asbestos fibers is associated with various forms of lung disease.
Amp - A measure of the amount of electrical current going through a circuit at any given time. Also see volt and watt.
Barometric damper - A delicately balanced air inlet shutoff that is found on flues or furnaces and boilers. The purpose is to control the air supply for combustion.
Back-up system - Auxiliary heating equipment that kicks in when the main unit—usually a heat pump or solar setup—can't handle the full load.
Balancing - Fine-tuning the air flow of a heating/cooling system to even up the delivery through a home.
Balusters - Spindles that help support a staircase handrail.
Bat - A half-brick.
Batt - A section of fiber-glass or rock-wool insulation measuring 15 or 23 inches wide by four to eight feet long.
Batten - A narrow strip used to cover joints between boards or panels.
Beam - A horizontal support member. Also see post and post-and-beam.
Bearing wall - An interior or exterior wall that helps support the roof or the floor joists above.
Biomass - Renewable fuels derived from plants; for example wood, grain alcohol, and methane from sewage.
Biscuit - a football shaped wafer of wood, usually compressed beech, designed to swell with the application of glue and used to key and strengthen glue joints in woodworking. Plastic biscuits are also used in special applications such as joining panels of special composition countertop material to join by use of biscuits.
Blankets - Fiber-glass or rock-wool insulation that comes in long rolls 15 or 23 inches wide.
Blocking - Small wood pieces to brace framing members or to provide a nailing base for gypsum board or paneling.
Blue print(s) - A type of copying method often used for architectural drawings. Usually used to describe the drawing of a structure which is prepared by an architect or designer for the purpose of design and planning, estimating, securing permits and actual construction.
Board Foot - A unit of measure for lumber equal to 1 inch thick by 12 inches wide by 12 inches long. Examples: 1" x 12" x 16'=16 board feet, 2" x 12" x 16'=32 board feet
Boiler - A heater that either heats water or converts water to steam for use in space-heating systems
Bond or bonding - An amount of money (usually $2,000-$6,000) which must be on deposit with the governmental agency in order to secure a contractor's license. The bond may be used to pay for the unpaid bills or disputed work of the contractor. Not to be confused with a 'performance bond'. Such bonds are rarely used in residential construction, they are an insurance policy which guarantees proper completion of a project.
Bond - The pattern in which bricks or other masonry units are laid. Also, the cementing action of an adhesive.
Bottom chord - The lower or bottom member of a truss.
Bracing - In a stick-built roof system it is the W-shaped structural member which provides support to the roof rafter. A piece of dimensional lumber or metal, used diagonally on the corner of a home. See corner brace.
Brick veneer - a four-inch brick wall used to provide an exterior finish for a house.
Btu (British Thermal Unit) - The amount of heat needed to raise one pound of water one degree
Building codes - Community ordinances governing the manner in which a home may be constructed or modified. Most codes primarily concern themselves with fire and health, with separate sections relating to electrical, plumbing, and structural work. Also see zoning.
Butt - To place materials end-to-end or end-to-edge without overlapping.
Butt hinge - The most common type. One leaf attaches to the door's edge, the other to its jamb.