A - B - C - D - E - F - G - H - I - J - K - L
M - N - O - P - Q - R - S - T - U - V - W - X - Y - Z

A/C Circuit - Alternating Current. The flow of current through a conductor first in one direction, then in reverse. It is used exclusively in residential and commercial wiring because it provides greater flexibility in voltage selection and simplicity of equipment design.
A/C Condenser - The outside fan unit of the air conditioning system. It removes the heat from the Freon gas and turns the gas back into a liquid and pumps the liquid back to the coil in the furnace.
ABS - A type of black plastic pipe commonly used for waste water lines. Real name is Acrylonitrile butadiene styrene.
Accessory Building - A building separate from the main structure on a property. Often used for a specific purpose, such as a workshop, storage shed or garage.
Acre - 43,560 square feet.
Addendum - A supplement to any document that contains additional information pertinent to the subject. Appraisers use an addendum to further explain items for which there was inadequate space on the standard appraisal form.
Aggregate - Crushed stone, slag or water-worn gravel that comes in a wide range of sizes which is used to surface built-up roofs.
Arc Fault Current Interrupters - AFIs or AFCIs - These are new electrical safety devices and are becoming part of the electrical codes. AFIs are designed to prevent electrical fires and should not be confused with GFIs. AFIs are recommended for bedroom areas.
Alligatoring - A condition of paint or aged asphalt brought about by the loss of volatile oils and the oxidation caused by solar radiation. Causes a coarse checking pattern characterized by a slipping of the new paint coating over the old coating to the extent that the old coating can be seen through the fissures. "Alligatoring" produces a pattern of cracks resembling an alligator hide and is ultimately the result of the limited tolerance of paint or asphalt to thermal expansion or contraction.
Aluminum Wire - A conductor made of aluminum for carrying electricity. Aluminum is generally limited to the larger wire sizes. Due to its lower conductivity, aluminum wire smaller than No. 12 is not made. Aluminum is lighter and less expensive than copper, but does not conduct as well. It also breaks easily.
Amperage or AMPS - A unit of electrical current or volume- (see Voltage)  Most homes have an electrical service 'entrance' package of 125 or 200 amps. Some older homes have 60 or 100 amp 'entrances'.
Anchor Bolts - In residential construction, "L" shaped bolts used to secure a wooden sill plate to a concrete or masonry floor or wall. In commercial construction, bolts which fasten columns, girders or other members to concrete or masonry such as bolts used to anchor sills to masonry foundation.
Angle Iron - A piece of iron that forms a right angle and is used to span openings and support masonry at the openings. In brick veneer, they are used to secure the veneer to the foundation.
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 - Asbestos is a mineral fiber. It can be positively identified only with a special type of microscope. There are several types of asbestos fibers. In the past, asbestos was added to a variety of products to strengthen them and to provide heat insulation and fire resistance.
Asphalt - A dark brown to black highly viscous hydrocarbon produced from the residue left after the distillation of petroleum. Asphalt is used on roofs and highways as a waterproofing agent.
Asphalt Plastic Cement - An asphalt-based cement used to bond roofing materials.
Awning Window - A window with hinges at the top allowing it to open out and up.

Backfill - The slope of the ground adjacent to the house. In any previously excavated area, i.e., the replacement of excavated earth into a trench around and against a basement foundation. In carpentry, the process of fastening together two pieces of board by gluing blocks of wood in the interior angle.
Backsplash - A raised integral portion of a wall mount sink or lavatory located at the rear to protect the wall.
Balloon Framing - In carpentry, the lightest and most economical form of construction in which the studding and corner plates are set up in continuous lengths from the first floor line or sill to the roof plate to which all floor joists are fastened.
Balusters - Usually small vertical members in a railing used between a top rail and the stair treads or a bottom rail.
Balustrade - A railing made up of balusters, top rail, and sometimes bottom rail, used on the edge of stairs, teal conies, and porches.
Barrel Roof - A roof design which in a cross section is arched.
Baseboard - Usually wood or vinyl installed around the perimeter of a room to cover the space where the wall and floor meet. A board placed against the wall around a room next to the floor to properly finish between the floor and the plaster.
Baseboard Heat - A heating system with the heating unit located along the perimeter of the wall where the baseboard would normally be located. It can be either an electric or hot water system.
Beam - A horizontal framing member designed to carry a load from a set of joists or a roof and spanning an open space. Usually 6" x 6" or 4" x 10" or larger.
Blister - An enclosed raised spot evident on the surface of a building. They are mainly caused by the expansion of trapped air, water vapour, moisture or other gases.
Blue Prints - 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 - The volume of a piece of wood measuring 12 inches square and in inch thick. A piece of lumber 1/2" thick and 6 inches wide and 24 inches long is equal to one board foot.
Brick Ledge - Part of the foundation wall where brick (veneer) will rest.
Brick Lintel - The metal angle iron that brick rests on, especially above a window, door, or other opening.
Brick Mold - Trim used around an exterior door jamb onto which siding butts.
Brick Tie - A small, corrugated metal strip (1"x6"- 8" long) nailed to wall sheeting or studs. They are inserted into the grout mortar joint of the veneer brick, and hold the veneer wall to the sheeted wall behind it.
Brick Veneer - A facing of brick laid against and fastened to the sheathing of a frame wall or tile wall construction.
BTU - A measure of the capacity of a heating or cooling system. Abbreviation of British Thermal Unit. The amount of heat energy required to raise the temperature of one pound of water through a change of one degree Fahrenheit.
Building Brick - Brick for building purposes not especially treated for texture or color, formerly called "common brick." It is stronger than face brick.
Building Code - Minimum local or state regulations established to protect health and safety. They apply to building design, construction, rehabilitation, repair, materials, occupancy and use. Community ordinances governing the manner in which a home may be constructed or modified.
Built-ins - Specific items of personal property which are installed in a real estate improvement such that they become part of the building. Built-in microwave ovens and dishwashers are common examples.
Built-Up Roof - A roofing composed of three to five layers of asphalt felt laminated with coal tar, pitch, or asphalt. The top is finished with crushed slag or gravel. Generally used on flat or low-pitched roofs.
BX Cable - Armoured electrical cable wrapped in galvanized steel outer covering. A factory assembly of insulated conductors inside a flexible metallic covering. It can be run anywhere except where exposed to excessive moisture. It should not be run below grade. It must always be grounded and uses its armour as an equipment ground. It is difficult to pull out old wires or insert new ones.

Calcium Carbonate - A white chalky material which is very often found on concrete basement walls and other concrete surfaces where water has leached some of the chemicals out of the concrete. Usually asign of past or present moisture penetrations.
Carbon Monoxide (CO) - A toxic colorless and odourless gas and common combustion by-product. CO testing must be a regular part of the annual gas furnace service. Combustion appliances including: furnaces, fireplaces, grills, generators, gas water heaters etc. require proper installation and service in order to prevent CO exposure.
Casement Window - A window with hinges on one of the vertical sides and swings open like a normal door.
Casing - Moulding of various widths and thicknesses used to trim door and window openings at the jambs.
Caulking - A flexible material used to seal a gap between two surfaces e.g. between pieces of siding or the corners in tub walls.
Cast-Iron Pipe - Drain and vent lines. Most older drain-waste venting systems are madeof cast-iron pipes. Now increasingly supplanted by ABS and PVC. Pipes were originally joined with molten lead, but most plumbers now join them with no-hub couplers.
Cellulose Insulation - Ground-up newspaper that is treated with a fire retardant.
Cement The gray powder that is the "glue" in concrete.
Ceramic Tile - A man-made or machine-made clay tile used to finish a floor or wall. Generally used in bathtub and shower enclosures and on counter tops.
CFM (Cubic Feet per Minute) - Cubic Feet of air moved per Minute. The higher the CFM number, the greater the vent’s capacity.
Chair Rail - A moulding that runs horizontally along the wall at about 3 feet from the ground. In storefront, window wall, or curtain wall systems, a chair rail is an aluminums extrusion applied horizontally to the inside of the system 3 feet from the floor to create a barrier in floor-to-ceiling glazing applications.
Chink - To install fiberglass insulation around all exterior door and window frames, wall corners, and small gaps in the exterior wall.
Chip Board - A manufactured wood panel made out of 1"- 2" wood chips and glue. Often used as a substitute for plywood in the exterior wall and roof sheathing. Also called OSB (Oriented Strand Board) or Wafer Board.
Circuit Breaker - A device which looks like a switch and is usually located inside the electrical panel or circuit breaker box. It is designed to (1) shut of the power to portions or all of the house and (2) to limit the amount of power flowing through a circuit (measured in amperes).
Cleanout - A drain fitting with a removable plug to permit inspection and access for an auger or snake.
Collar - In roofing, a conical metal cap flashing used in conjunction with vent pipes or stacks usually located several inches above the plane of the roof for the purpose of shedding water away from the base of the vent.
Collar Beam - In carpentry, a tie that keeps the roof from spreading. They serve to stiffen the roof structure. Connects similar rafters on opposite sides of
roof. Collar Tie - A horizontal board attached perpendicular to rafters.
Column - In architecture: A perpendicular supporting member, circular or rectangular in section, usually consisting of a base, shaft, and capital. In engineering: A vertical structural compression member which supports loads acting in the direction of its longitudinal axis.
Combustion Air - The duct work installed to bring fresh, outside air to the furnace and/or hot water heater. Normally 2 separate supplies of air are brought in: one high and one low.
Combustion Chamber - The part of a boiler, furnace or woodstove where the burn occurs; normally lined with firebrick or moulded or sprayed insulation.
Concrete - A common construction material often used for foundations, ground level floors, and sidewalks. Most concrete is made out of (1) Portland cement, (2) sand, and (3) gravel or aggregate. It is commonly reinforced with steel rods (rebar) or wire screening (mesh).
Concrete Block - A hollow concrete 'brick' often 8" x 8" x 16" in size. Often used in low rise commercial and some residential construction.
Condensation - The change of water from vapour to liquid when warm, moisture-laden air comes in contact with a cold surface.
Control Joint - A control joint controls or accommodates movement in the surface component of a roof.
Copper Pipes - Type K has the heaviest or thickest wall and is generally used underground. Type L has a medium wall thickness and is most commonly used for water service and for general interior water piping. Type M has a thin wall and many codes permit its use in general water piping installation.
Counter Flashing - The formed metal secured to a wall, curb, or roof top unit to cover and protect the upper edge of a base flashing and its associated fasteners. This type of flashing is usually used in residential construction on chimneys at the roofline to cover shingle flashing and to prevent moisture entry.
CPVC (Chlorinated Polyvinyl Chloride) - Rigid plastic pipe used in water supply systems where code permits.
Cripple Stud - Short stud used as support in wall openings that replaces a normal 93 inch or 96 inch stud.
Cripple Walls - In a wood-frame house, the section of wall under the house between the concrete foundation and the floor joists. Also called crawl space walls.
Cross-Bridging - Diagonal bracing between adjacent floor joists, placed near the center of the joist span to prevent joists from twisting.
Crosscutting - Cutting across the wood grain; to crosscut a board is to cut across its width.
Crown Moulding - A moulding used on cornice or wherever an interior angle is to be covered.
Curing - In concrete application, the process in which mortar and concrete harden. The length of time is dependent upon the type of cement, mix proportion, required strength, size and shape of the concrete section, weather and future exposure conditions. The period may be 3 weeks or longer for lean concrete mixtures used in structures such as dams or it may be only a few days for richer mixes. Favourable curing temperatures range from 50 to 70 degrees Fahrenheit. Design strength is achieved in 28 days.

Dado - A rectangular groove across the width of a board or plank. In interior decoration, a special type of wall treatment.
Damper - An air valve that regulates the flow of air inside the flue of a furnace or fireplace.
Damp proofing - A process used on concrete, masonry or stone surfaces to repel water, the main purpose of which is to prevent the coated surface from absorbing rain water while still permitting moisture vapour to escape from the structure. (Moisture vapour readily penetrates coatings of this type.) "Damp proofing" generally applies to surfaces above grade; "waterproofing" generally applies to surfaces below grade.
De-humidistat - A control mechanism used to operate a mechanical ventilation system based upon the relative humidity in the home.
Dead Load - The constant, design-weight (of the roof) and any permanent fixtures attached above or below.
Deck (roofing) - The surface, installed over the supporting framing members, to which the roofing is applied.
Dormer - A roof gable which is usually located at right angles to the main roof structure. Used to increase head room or as an architectural detail.
Double Hung Window - A window with two vertically sliding sashes. This common older window design was usually made out of wood and tends to require frequent repairs.
Double-Glazing - In general, any use of two lights of glass, separated by an air space within an opening to improve insulation against heat transfer and/or sound transmission. In insulating glass units, the air between the glass sheets is thoroughly dried and the space is sealed, eliminating possible condensation and providing superior insulating properties.
Downspout - The pipe that carries water down from the gutter or scupper. Also called a leader.
Drip Cap - A moulding placed on the exterior top side of a door or window frame to cause water to drip beyond the outside of the frame.
Drip Edge - A corrosion-resistant, non-staining material used along the eaves and rakes to allow water run-off to drip clear of underlying construction.
Drywall, (Sheet rock or Plasterboard) - A wall finish consisting of a manufactured panel made out of gypsum plaster and encased in a thin cardboard. Usually 1/2" thick and 4' x 8' or 4' x 12' in size. The panels are nailed or screwed onto the framing and the joints are taped and covered with a 'joint compound'. 'Green board' type drywall has a greater resistance to moisture than regular (white) plasterboard.

Eaves - The horizontal, lower edge of a sloped roof which typically overhangs the walls.
Efflorescence- A white chalky material which is very often found on concrete basement walls and other concrete surfaces where water has leached some of the chemicals out of the concrete. Usually a sign of past or present moisture penetrations.
Egress - A means of exiting the home. An egress window is required in every bedroom and basement. Normally a 4x4 window is the minimum size required.
EIFS - Exterior Insulating and Finish System; exterior wall cladding system consisting primarily of polystyrene foam board with a textured acrylic finish that resembles plaster or stucco.
Elastomer - An elastic rubber-like substance, such as natural or synthetic rubber.
Elastomeric - Of or pertaining to any of the numerous flexible membranes that contain rubber or plastic.
Errors and Omissions Insurance - An insurance policy taken out by appraisers to cover their liability for any mistakes made during the appraisal process.
Expansion Joint - A device used to permit a structure to expand or contract without breakage. In residential construction, a bituminous fiber strip used to separate blocks or units of concrete to prevent cracking due to expansion as a result of temperature changes. Also used on concrete slabs.
Expansive Soils - Earth that swells and contracts depending on the amount of water that is present.
Exterior Envelope - of a building consists of all of the elements protecting the building from the elements: roofing, siding, windows, exterior doors, porches, flashing, trim, caulking, chimneys and other elements which relate to the exterior surfaces of the structure.

Fascia - A vertical wood member, such as a cedar 1" x 6", which is nailed to the ends of the rafters and is often the backing of the gutter.
Fire Block - Short horizontal members sometimes nailed between studs, usually about halfway up a wall. See also 'Fire Stop.'
Fire Brick - Brick made of refractory ceramic material which will resist high temperatures. Used in fireplaces and boilers.
Fire Stop - A solid, tight closure of a concealed space, placed to prevent the spread of fire and smoke through such a space. In a frame wall, this will usually consist of 2x4s cross blocking between studs.
Fire Wall - Any wall built for the purpose of restricting or preventing the spread of fire in a building. Such walls of solid masonry or concrete generally sub-divide a building from the foundations to two or more feet above the plane of the roof.
Flashing - The building component used to connect portions of a roof, deck, or siding material to another surface such as a chimney, wall, or vent pipe. Often made out of various metals, rubber or tar and is mostly intended to prevent water entry.
Flue - A pipe used to exhaust smoke, gas or air.
Flue Collar - Round metal ring which fits around the heat flue pipe after the pipe passes out of the roof.
Flue Damper - An automatic door located in the flue that closes it off when the burner turns off; its purpose is to reduce heat loss up the flue from the still-warm furnace or boiler.
Flue Lining - Fire clay or terracotta pipe, round or square, usually made in all ordinary flue sizes and in 2-foot lengths, used for the inner lining of chimneys with the brick or masonry work around the outside. Flue lining in chimneys runs from about a foot below the flue connection to the top of the chimney.
Fluorescent Lighting - A fluorescent lamp is a gas-filled glass tube with a phosphor coating on the inside, normally with two pins that extend from each end. Gas inside the tube is ionized by electricity which causes the phosphor coating to glow.
Footings - Wide pours of cement reinforced with re-bar (reinforcing bar) that support foundation walls, pillars, or posts. Footings are part of the foundation and are often poured before the foundation walls.
Forced Air Heating- A common form of heating with natural gas, propane, oil or electricity as a fuel. Air is heated in the furnace and distributed through a set of metal plastic ducts to various areas of the house.
Form - Temporary structure erected to contain concrete during placing and initial hardening.
Foundation - The supporting portion of a structure below the first floor construction, or below grade, including the footings.
Framing - The structural wood and/or metal elements of most homes. The floor and ceiling framing is called the joist work. Wall framing is usually made out of 2" x 4" or 2" x 6" studs.
Furnace - A heating system that uses the principle of thermal convection. When air is heated, it rises and as the air cools it settles. Ducts are installed to carry the hot air from the top of the furnace to the rooms. Other ducts, called cold air returns, return the cooler air back to the furnace.
Furring - Strips of wood or metal applied to a wall or other surface to even it and normally to serve as a fastening base for finish material.
Fuse - A device often found in older homes designed to prevent overloads in electrical lines.

Gable - The upper portion of a sidewall that comes to a triangular point at the ridge of a sloping roof.
Gable Roof - A steeply angled, triangular roof.
Gambrel Roof - A "barn-like" roof, where the upper portion of the roof is less-steeply angled than the lower part.
GFI or GFCI or Ground Fault Current Interrupter - A electrical device used to prevent injury from contact with faulty electrical appliances and faulty wiring - electrical shocks. GFIs should not be confused with AFIs, the later are designed to prevent electrical fires. GFIs are required in new home bathrooms, kitchen, garage, out of doors and in other locations where one might be in contact with a grounded surface and an electrical appliance. Most GFI's are located in the receptacle itself and can be identified by the presence of a 'test' and a 'reset' button.
Glued Laminated Beam (Glulam) - A structural beam composed of wood laminations or lams. The lams are pressure bonded with adhesives to attain a typical thickness of 1 ½" . (It looks like 5 or more 2x4s are glued together).
Ground System - The connection of current-carrying neutral wire to the grounding terminal in the main switch which in turn is connected to a water pipe. The neutral wire is called the ground wire.
Grounding Rod - Rod used to ground an electrical panel.
Gusset - A flat wood, plywood, or similar type member used to provide a connection at intersection of wood members. Most commonly used at joints of wood trusses. They are fastened by nails, screws, bolts, or adhesives.
Gutter - Metal or plastic trough at the eaves of a roof to carry rain water from the roof to the downspout.


H Clip - Small metal clips formed like an "H" that fits at the joints of two plywood (or wafer board) sheets to stiffen the joint. Normally used on the roof sheeting.
Heat pump - A device which uses compression and decompression of gas to heat  and /or cool a house.
Hip - The external angle formed by the meeting of two sloping sides of a roof.
Hip Rafter - A rafter that forms the intersection of an external roof angle.
Hip Roof - A roof that rises by inclined planes from all four sides of a building.
Hip Shingles - Shingles used to cover the inclined external angle formed by the intersection of two sloping roof planes.
Hot Wire - The wire that carries electrical energy to a receptacle or other device—in contrast to a neutral, which carries electricity away again. Normally the black wire. Also see Ground.
Hot Water Heating (Hydronic Heating) - A heating system which uses various types of fuel to heat water which is then distributed through pipes to radiators located in various portions of the house.
Hub - In plumbing, the enlarged end of a pipe which is made to provide a connection into which the end of the joining pipe will fit.
Humidifier - A device designed to increase the humidity within a room or a house by means of the discharge of water vapor. They may consist of individual room size units or larger units attached to the heating plant to condition the entire house.
HVAC - Heating Ventilation and Air Conditioning.

I-Beam - A steel beam with a cross section resembling the letter "I." It is used for long spans as basement beams or over wide wall openings, such as a double garage door, when wall and roof loads are imposed on the opening.
I-Joist - Manufactured structural building component resembling the letter "I." Used as floor joists and rafters. I-joists include two key parts: flanges and webs. The flange of the I joist may be made of laminated veneer lumber or dimensional lumber, usually formed into a 1 ½" width. The web or center of the I-joist is commonly made of plywood or oriented strand board (OSB). Large holes can be cut in the web to accommodate duct work and plumbing waste lines. I-joists are available in lengths up to 60 feet long.
Ice Dams - A condition which can occur with snow and freezing conditions. When snow or ice melts on a roof over a heated or partially heated attic space, the melting water may refreeze over an unheated areas such as a roof overhang. This re-frozen water may create a "dam" and allow additional melt water to back up under shingles and cause leaks.
ID (Inside Diameter) - The diameter measurement taken from the inside of a pipe. A common method for sizing pipe.
Incandescent Lamp - A lamp employing an electrically charged metal filament that glows at white heat. A typical light bulb.
Insulating Glass - Window or door in which two panes of glass are used with a sealed air space between. Also known as Double Glass.
Insulation - Generally, any material which slows down or retards the flow or transfer of heat. Building insulation types are classified according to form as loose-fill, flexible, rigid, reflective, and foamed-in-place. All types are rated according to their ability to resist heat flow (R-Value). In electrical contracting, rubber, thermoplastic, or asbestos wire covering. The thickness of insulation varies with wire size and type of material, application or other code limitations.
Irrigation - Lawn sprinkler system.

Jack Post - A type of structural support made of metal which can be raised or lowered through a series of pins and a screw to meet the height required. Basically used as a replacement for an old supporting member in a building. See Monopost.
Jamb - The side and head lining of a doorway, window, or other opening.
Joint - The space between the adjacent surfaces of two members or components joined and held together by nails, glue, cement, mortar, or other means.
Joint Compound - A material applied to threaded connections to help prevent leaks in plumbing. Also, in carpentry, a wet gypsum material applied to sheetrock joints.
Joists - A framing member, often a 2" x 10" piece of lumber, which is usually spaced every 16" to 24" and supports the sub-floor and flooring. The joist usually 'sits' on a load bearing wall or beam.
Joist Hanger - A metal "U" shaped item used to support the end of a floor joist and attached with hardened nails to another bearing joist or beam.

Kilowatt (KW) - One thousand watts. A kilowatt hour is the base unit used in measuring electrical consumption.
King Stud - The vertical 2x4 frame lumber (left and right) of a window or door opening, and runs continuously from the bottom sole plate to the top plate.


Laminated Shingles - Shingles that have added dimensionality because of extra layers or tabs, giving a shakelike appearance. May also be called "architectural shingles" or "three-dimensional shingles."
Landing - A platform between flights of stairs or at the termination of a flight of stairs.
Lath - A building material of wood, metal, gypsum, or insulating board that is fastened to the frame of a building to act as a plaster base.
Lath and Plaster - The most common wall finish prior to the introduction of drywall. Thin wood strips (lath) were nailed onto the framing as a base for the sand/lime plaster.
Lattice - A framework of crossed wood or metal strips.
Leach field - A method used to treat/dispose of sewage in rural areas not accessible to a municipal sewer system. Sewage is permitted to be filtered and eventually discharged into a section of the lot called a leech field.
Lineal 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.
Lintel - A horizontal structural member that supports the load over an opening such as a door or window.
Live Load - Loads produced by use and occupancy of the building or other structure and do not include construction or environmental loads such as wind load, snow load, ice load, rain load, seismic load, or dead load.
Load Bearing Wall - A wall which is supporting its own weight and some other structural elements of the house such as the joists.

Mansard Roof - A roof which rises by inclined planes from all four sides of a building. The sloping roofs on all four sides have two pitches, the lower pitch usually very steep and the upper pitch less steep.
Mantel - The shelf above a fireplace. Also used in referring to the decorative trim around a fireplace opening.
Manufactured Wood - A wood product such as a truss, beam, or joist which is manufactured out of smaller wood pieces and glued or mechanically fastened to form a larger piece. Often used to create a stronger member which may use less wood.
Masonry - Stone, brick, concrete, hollow-tile, concrete block, gypsum block, or other similar building units or materials or a combination of the same, bonded together with mortar to form a wall, pier, buttress, or similar mass.
Microlam - A manufactured structural wood beam. It is constructed of pressure and adhesive bonded wood strands of wood. They have a higher strength rating than solid saw lumber. Normally comes in l ½" thickness' and 9 ½", 11 ½" and 14" widths.
Modified Bitumen Roof - A roof covering that is typically composed of a factory-fabricated composite sheet consisting of a copolymer-modified bitumen, often reinforced with polyester and/or fiberglass, and installed in one or more plies. The membrane is commonly surfaced with field-applied coatings, factory-applied granules or metal foil. The roofing system may incorporate rigid insulation.
Mopping - In roofing, a layer of hot bitumen mopped between plies of roofing felt. Full mopping is the application of bitumen by mopping in such a manner that the surface being mopped is entirely coated with a reasonably uniform coating. Spot Mopping is the procedure of applying hot bitumen in a random fashion of small daubs, as compared to full mopping. Sprinkle mopping is a special application of installing insulation to the decks. It is done by dipping a roof mop into hot bitumen and sprinkling the material onto the deck. Strip Mopping is the application of bitumen in parallel bands.
Mullion - A vertical bar or divider in the frame between windows, doors, or other openings that supports and holds such items as panels, glass, sash, or sections of a curtain wall.
Muntins - Horizontal or vertical bars that divide the sash frame into smaller lights of glass. Muntins are smaller in dimensions and weight than mullions.

O-Ring - Round rubber washer or gasket that is compressed to create a watertight seal, typically in a compression fitting.
Ogee - A molding with a profile in the form of a letter S; having the outline of a reversed curve.
On Center (O.C.) - A measurement term meaning a certain distance between like materials. Studs rafters, joists, and the like in a building placed at 16 inches O.C. will be laid out so that there is 16 inches from the center of one stud to the center of the next.
Oriented Strand Board or OSB or Chip Board or Wafer Board - A manufactured wood panel made out of 1"- 2" wood chips and glue. Often used as a substitute for plywood in the exterior wall and roof sheathing.


P Trap - P-shaped section of drain pipe that prevents sewer odors from escaping into your home. Water is trapped in the pipe blocking gases from escaping through the drain.
Parapet Wall - A low wall around the perimeter of a roof deck.
Parge Coat - A thin application of plaster for coating a wall.
Penny - As applied to nails, it originally indicated the price per hundred. The term now serves as a measure of nail length and is abbreviated by the letter "D."
Perimeter Drain - 4" perforated plastic pipe that goes around the perimeter (either inside or outside) of a foundation wall (before backfill) and collects and diverts ground water away from the foundation. Generally, it is "daylighted" into a sump pit inside the home, and a sump pump is sometimes inserted into the pit to discharge any accumulation of water.
Pigtails The electric cord that the electrician provides and installs on an appliance such as a garbage disposal, dishwasher, or range hood.
Pilot Hole - A small-diameter, pre-drilled hole that guides a nail or screw.
Platform Framing - A system of framing a building in which floor joists of each story rest on the top plates of the story below or on the foundation sill for the first story, and the bearing walls and partitions rest on the subfloor of each story. (Usually one story constitutes a platform.)
Plenum - Chamber or container for moving air under a slight positive pressure to which one or more ducts are connected.
Plumbing Stack - A plumbing vent pipe that penetrates the roof.
Plywood - A piece of wood made of three or more layers of veneer joined with glue, and usually laid with the grain of adjoining plies at right angles. Almost always an odd number of plies are used to provide balanced construction.
Point Load - A point where a bearing/structural weight is concentrated and transferred to the foundation.
Pointing - The process where joints between masonry units, brick, etc., are filled with mortar.
Polyvinyl Chloride PVC or CPVC - A type of white plastic pipe sometimes used for water supply lines.
Plans - See Blue Prints
Plasterboard - See Drywall
Polybutylene - A type of plastic pipe (often gray in color) sometimes used in domestic water supply systems.
Polyisocyanurate Foam - A rigid foam board insulation often used in locations where there is not enough room for standard batt insulation. One of the least expensive ways to reduce energy consumption.
Post - A vertical framing member usually designed to carry a beam. Often a 4" x 4", a 6" x 6", or a metal pipe with a flat plate on top and bottom.
Pressure Relief Valve - A device mounted on a hot water heater or boiler which is designed to release any high steam pressure in the tank and thus prevent tank explosions.

R-Value - The thermal resistance of a glazing system. The R-value is the reciprocal of the U-value. The higher the R value, the less heat is transmitted throughout the glazing material.
Radiant Heat - A heating system which uses hot water or steam pipes, or electric resistance coils to heat the floors, walls or the ceiling of a room.
Radon - A naturally-occurring, radioactive gas which is heavier than air and is common in many parts of the country. Radon gas exposure is associated with lung cancer. Mitigation measures may involve crawl space and basement venting and various forms of vapor barriers.
Rafter - The framing member which directly supports the roof sheathing. A rafter usually follows the angle of the roof, and may be a part of a roof truss.
Rafter Tail - The portion of a rafter that extends past the building to form the eaves.
Ranch - A single story, one level home.
Reinforced Concrete - A combination of steel and concrete using the best properties of each. The steel consists of rebar or reinforcing bars varying from 3/8 " to 2 1/4 " in diameter and is placed before concrete is poured.
Relative Humidity - The amount of moisture in a volume of air as a percentage of the maximum amount of moisture which can be held in that air at a certain temperature - cold air can't hold as much moisture as warm air.
Resilient Flooring - A durable floor cover that has the ability to resume its original shape.
Retaining Wall - A structure that holds back a slope and prevents erosion.
Ridge - The horizontal line at the junction of the top edges of two sloping roof surfaces. The rafters of both slopes are nailed to a board at the ridge.
Riser - The upright section of a stair. The board between one stair tread and the next.
Roll Roofing - Roofing material, composed of fiber and satin rated with asphalt, that is supplied in 36-inch wide rolls with 108 square feet of material. Weights are generally 45 to 90 pounds per roll.
R Value - A measure of insulation. For example, typical new home's walls are usually insulated with 6" of batt insulation with an R value of R-19, and a ceiling insulation of R-28.
Roof Certification - A written opinion by a roofing professional (contractor or inspector) regarding the expected remaining useful life of a roof system (roofing, venting, flashing...).
Run - The horizontal distance between the eaves and the ridge of the roof, being half the span for a symmetrical gable roof. Also, the net width of a step or the horizontal distance covered by a flight of stairs.


Sanitary Sewer - A sewer system designed for the collection of waste water from the bathroom, kitchen and laundry drains, and is usually not designed to handle storm water.
Sash - The frame that holds the glass in a window, often the movable part of the window.
Septic System - An on site waste water treatment system. It usually has a septic tank which promotes the biological digestion of the waste, and a drain field which is designed to let the left over liquid soak into the ground.
Setback Thermostat - A thermostat with a clock which can be programmed to various temperatures at different times of the day/week. Usually used as the heating or cooling system thermostat.
Shake or Shingle - A wood, usually cedar, roofing product which is produced by splitting a block of the wood along the grain line. Modern shakes are sometimes machine sawn on one side.
Sheathing - The plywood, board, OSB or other material used as the base for the roofing.
Sheet rock - See Drywall Shutoff Valve - The valve that allows water supply to be cut off to one fixture without affecting the water supply to the entire house or building. Common for use with clawfoot tubs, sinks, and toilets.
Silicone Sealant - A sealant having as its chemical compound a backbone consisting of alternating silicon-oxygen atoms.
Sill - The lowest member of the frame of a structure, resting on the foundation and supporting the floor joists or the uprights of the wall. The member forming the lower side of an opening, as in a door sill, window sill, etc.
Sleeper - Usually, a wood member embedded in concrete, as in a floor, that serves to support and to fasten subfloor or flooring.
Soffit - A small ceiling-like space, often out of doors, such as the underside of a roof overhang.
Splash Block - A pad which is placed under the lower end of a downspout and diverts the water from the downspout away from the house. Not the most effective means of diverting roof water.
Square (roofing) - A unit of measure, e.g. 100 square feet, usually applied to roofing material. Sidewall coverings are sometimes packed to cover 100 square feet and are sold on that basis.
Square Foot - Coverage measured by multiplying width by length. An area 5 foot long and 7 foot wide is equal to 35 square foot.
Stack Vent - Also called a waste vent or soil vent, it is the extension of a soil or waste stack above the highest horizontal drain connected to the stack.
Static Load - The total amount of permanent non-moving weight that is applied to given surface areas.
Storm Sewer - A sewer system designed to collect storm water and is separated from the waste water system.
Sump Pump - A submersible pump in a sump pit that pumps any excess ground water to the outside of the home.
Suspended Ceiling - A ceiling system supported by hanging it from the overhead structural framing.
Sway Brace - Metal straps or wood blocks installed diagonally on the inside of a wall from bottom to top plate, to prevent the wall from twisting, racking, or falling over "domino" fashion.


Termites - Insects that superficially resemble ants in size, general appearance, and habit of living in colonies; hence, they are frequently called "white ants." Subterranean termites establish themselves in buildings not by being carried in with lumber, but by entering from ground nests after the building has been constructed. If unmolested, they eat the woodwork, leaving a shell of sound wood to conceal their activities, and damage may proceed so far as to cause collapse of parts of a structure before discovery. There are about 56 species of termites known in the United States but the two major ones, classified by the manner in which they attack wood, are ground inhabiting or subterranean termites (the most common) and dry wood termites, which are found almost exclusively along the extreme southern border and the Gulf of Mexico in the United States.
Three-Phase - In electrical contracting, a wiring system consisting of 4 wires and used in industrial and commercial applications. This system is suitable for installations requiring large motors. It consists of three hot wires and one ground wire. The voltage in each hot wire is out of phase with the others by 1/3 of a cycle, as if produced by 3 different generators.
TJI or TJ - Manufactured structural building component resembling the letter "I." Used as floor joists and rafters. I-joists include two key parts: flanges and webs. The flange may be made of laminated veneer lumber or dimensional lumber, usually formed into a 1½" width. The web is commonly made of plywood or oriented strand board (OSB). Large holes can be cut in the web to accommodate duct work and plumbing waste lines. I-joists are available in lengths up to 60'' long.
Toe-Nailing - To drive a nail at a slant to the initial surface in order to permit it to penetrate into a second member.
Tongue and Groove - A type of flooring where the tongue of one board is joined to the groove of another board.
Treated Lumber - A wood product which has been impregnated with chemicals to reduce damage from wood rot or insects. Often used for the portions of a structure which is likely to be in ongoing contact with soil and water. Wood may also be treated with a fire retardant.
Truss - A manufactured wood member often in the form of a large triangle which is used to form the ceiling joists and rafters on the top floor of a home.
Tube and Knob Wiring - A common form of electrical wiring used before W.W.II.

Vapour Barrier - A membrane which is placed between the insulation and the roof deck to retard water vapor in the building from entering the insulation and condensing into liquid water.
Vent Pipe - A vertical pipe of relatively small dimensions which protrudes through a roof to provide for the ventilation of gasses.
Vent Stack - A vertical vent pipe installed for the purpose of providing circulation of air to and from any part of a drainage system.
Vermiculite - An aggregate somewhat similar to perlite that is used as an aggregate in lightweight roof decks and deck fills. It is formed from mica, a hydrous silicate with the ability of expanding on heating to form lightweight material with insulation quality. Used as bulk insulation and also as aggregate in insulating and acoustical plaster and in insulating concrete.
Voltage - A measure of electrical potential. Most homes are wired with '110' and '220' volt lines. The '110' volt power is used for lighting and most of the other circuits. The '220' volt power is usually used for the kitchen stove, water heater and dryer.

Wafer Board - See Oriented Strand Board
Watt - A measure of the electrical requirement of an appliance calculated by multiplying voltage x amperage. For example; a 1600 watt hair dryer which uses '110' volt power needs about 15 amps.

Zoning - A governmental process and specification which limits the use of a property e.g. single family use, high rise residential use, etc.