Glossary of Terms

AIR CHAMBER Chamber or capped pipe filled with air to prevent water hammer.

AMPERE: The unit of electrical current by which the volume of electricity is measured.

ASBESTOS: A generic term given to a group of naturally occurring mineral fibers. Asbestos exists as part of the earth's crust. Many different mineral types of asbestos exist as part of the earth's crust and depend upon the rock types that form the asbestos. The most common types of asbestos are: Serpentines; chrysotile (white asbestos); and Amphiboles: amosite (brown asbestos), crocidolite (blue asbestos), antinolite, anthophylite and tremolite. Asbestos is extracted from open pit mines and was used extensively in residential buildings between 1900 and the mid 1980's.

ASPHALT: A residue from evaporated petroleum. It is insoluble in water but soluble in gasoline and melts when heated. Used widely in buildings for waterproofing roof coverings and as paving material.

BACKFILL: The earth replaced in the excavated areas around the foundation wall after the foundation is in place.

BITUMEN: A generic term used for either asphalt or coal tar pitch.

CIRCUIT: A branch of the main electrical system which brings electricity to appliances or to a room in the house via switches and outlets.

CIRCUIT BREAKER: A switch that senses current overload on a circuit and automatically shuts it off to prevent overheating or overcurrent.

CLASS A/CLASS C SHINGLE: A rating by the Underwriters Laboratories given to roofing material indicating its ability to withstand exposure to fire originating from outside the house or building.

CLEANOUT: A capped opening to drainlines and some traps to facilitate removal of a blockage with a plumber's snake or auger. A covered opening to clean out ash and creosote residue from chimneys and fireplaces.

CORNICE: The trim at the eave line, usually consisting of a fascia board, a soffit for a closed cornice, and appropriate moldings.

CRAWL SPACE: A shallow, unfinished space beneath the living space of a house used for visual inspection and access to pipes and ducts.

CRICKET/SADDLE: A small false roof that is constructed in order to throw off water from behind an obstacle, such as a chimney.

CROSS CONNECTION: Any situation which allows contact between potable water and sewage or water which is not safe to drink.

DELAMINATION: The separation of the layers of plywood sheathing due to exposure to moisture.

DOWNSPOUT, OR LEADER: Piping which carries rain water from the roof or gutter. An extension on the end of a downspout used to direct water runoff away from the house foundation.

DRIP EDGE: A piece of metal placed over the roof sheathing at the perimeter to deflect water away from the sheathing and fascia board.

EAVE: The lower part of a roof where it meets or projects over a wall.

EFFLORESCENCE:  Whitish, powdery salt stains that are left on masonry surfaces and plumbing pipes after moisture evaporates.

ELECTRICITY:   The result of electrons flowing through a conductor.

FASCIA:  A flat board, band or face located at the outer edge of the cornice, parallel to with the exterior house face, and secured to the house face.

FLASHING: Sheet metal or other material used in roof construction to prevent water seepage between joints, around plumbing vents, at the base of chimneys, at valleys or where stepped roofs abut the exterior house walls.

FOUNDATION:  Lower supporting walls, columns or slabs on which the structure is built.

FOUNDATION VENT:  An opening which permits the passage of air.

FUSE: A device located at the main service panel or subpanel, which protects each circuit from a current overload. Screw-in fuses are used in panel boxes and subpanels to protect 120 volt circuits up to 30 amps. Cartridge type fuses, held in clips, are used to protect 240 volt circuits drawing 20 or more amps.

GALVANIZED PIPE:  Steel pipe covered with zinc to resist corrosion.

GRADE LINE:  The height which the top of the soil reaches all along the perimeter of the house.

GROUND:  A conductor that leads directly, or through other conductors, to the earth.

GROUND-FAULT CIRCUIT INTERRUPTER(GFCI): A device which automatically opens the circuit when it senses a current leak to ground. Designed to prevent personal injury when electrical equipment is operated, it is particularly helpful in a damp or wet environment.

GUTTER:  A channel at the roof edge for collecting rain water. Gutters are sloped towards downspouts and secured to the house with gutter clips or screws.

HYDROSTATIC PRESSURE:  The pressure exerted by an accumulation of water under a basement floor or at below grade foundation areas of the house from the exterior.

INSULATOR:  Any material which inhibits the flow of electricity.

LEADER:  See downspout.

LOUVER: An opening with a series of horizontal slats which permit ventilation but exclude rain and vision.

MAIN SERVICE PANEL: The location from which incoming power is divided and fed throughout the house along a series of branch circuits.

MASTIC:   A material used as a roofing cement. An adhesive used like a glue or cement. Any one of various cements or mortars having a pasty texture

OVERLOAD:   A condition caused when too much current flows through a conductor. Overloaded conductors overheat, and may cause fires.

PAPER: A Building material, usually asphalt impregnated cellulose or felt, used in roof construction to prevent the passage of air and water.

PARAPET:   A low wall at the edge of a platform or flat roof that projects above the roof line. It is the top of the firewalls in multi-family buildings.

POINTING:  Filling of masonry joints.

POLARITY:  The correct flow of electricity that is achieved when the hot and neutral wires of the power supply circuits are connected to the corresponding hot and neutral wires of an appliance.

PSI:  Pounds per square inch of pressure.

RAFTER:  One of a series of structural members of a roof designed to support the roof surface and load.

REVERSED POLARITY:  A potentially hazardous situation, in which the hot and neutral wires of a circuit are reversed at the outlet, thereby allowing an appliance to be incorrectly connected.

RIDGE:  The horizontal line at the junction of the top edges of two sloping roof surfaces.

SERVICE ENTRANCE:  The cable that carries current from the utility company's service drop to the main disconnect.

SHEATHING:  The boards or sheet material which are fastened to the roof rafters to cover the house.

SHINGLES:  Roof covering of asphalt, asbestos, wood, tile, slate or other material cut to stock lengths, widths and thickness'.

SHORT CIRCUIT:  The condition that exists when a live wire touches any grounded or neutral bare wire or metal (such as a switch plate cover) somewhere along the circuit.

SIPHONAGE:  Vacuum action which can draw water out of traps if atmospheric pressure is not maintained.

SOFFIT:  The underside of an overhanging cornice.

SOIL PIPE:   Any pipe which handles discharge from the toilet.

SPLASH BLOCK:  A concrete or fiberglass pan placed under a downspout to catch water, dissipate its force, and lead it away from the foundation wall.

STEP FLASHING:  The interweaving of flashing with the roofing material and the materials of a vertical wall surface, required whenever a vertical wall meets the roofing surface (such as in the case of a dormer, skylight, garage or chimney).

SUMP:  A pit in which water collects to be pumped out with a sump pump.

SWALE:  A shallow depression in the ground for storm water drainage.

SWEATING:  Condensation formed by moisture vapor in warm air coming in contact With a cold surface. Can also mean the joining of copper pipes with solder.

TRAP:  A water filled "U" shaped pipe which prevents sewer gases from flowing into a building.

TRUSS:  The engineered components which have supplemental rafters in many newer houses. They are designed for specific applications and cannot be cut or altered in any way.

VALLEY:  The joint formed by the junction of two sloping sides of a roof.

VENT SYSTEM:  Piping system which maintains atmospheric pressure to prevent siphonage of trap water seals, and allows discharge of sewer vapors to the outside.

VOLT: The unit of electrical force used to measure the "pressure" with which electricity is pushed through a conductor.

WASTE PIPE:  A pipe which handles discharge from any fixture other than the toilet.

WATER HAMMER:  Sound of water under pressure coming to an abrupt halt within a piping system.

WATER TABLE:  The natural level of water in the earth. This changes from location to location and according to the seasons of the year and soil conditions.

WATT:  The unit by which electrical power consumption is measured. It is calculated by multiplying the voltage in a circuit by the number of amps being used by the appliance or other load.