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.

Amperage
The strength of an electric current as measured in amperes.

Ampere
A measure of the amount of electrical current going through a circuit at any given time.

Back-up system
Auxiliary equipment that kicks in when the main unit 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.

Bearing wall
An interior or exterior wall that helps support the roof or the floor joists above.

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.

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 12" = 1 board foot
1" x 12" x 12' = 12 board feet
2" x 12" x 12' = 24 board feet

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.

Brick veneer
A brick facing used over a sub-wall 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 Fahrenheit. Heating and cooling equipment commonly is rated by the BTUs it can deliver or absorb.

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.

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.

Cantilever
A beam or beams projecting beyond a support member.

Casing
Trim work around a door, window, or other opening.

Caulk
Any of a variety of different compounds used to seal seams and joints against infiltration of water and air.

Ceiling joist
One of a series of parallel framing members used to support ceiling loads and supported in turn by larger beams, girders or bearing walls.

Cement
A powder that serves as the binding element in concrete and mortar. Also, any adhesive.

Ceramic tile
A man-made or machine-made clay tile used to finish a floor or wall.

CFM
(cubic feet per minute). A rating that expresses the amount of air a blower or fan can move.

Chalking
The tendency of some exterior paints to gradually erode away over a period of time.

Circuit breaker
A protective switch that automatically shuts off current in the event of a short or overload.

Class 'A'
Optimum fire rating issued by Underwriter's Laboratories on roofing. The building code in some areas requires this type of roofing for fire safety.

Class 'C'
Minimum fire rating issued by the Underwriters' Laboratories for roofing materials.

Compression web
A member of a truss which connects the bottom and top chords and provides downward support.

Compressor
The part of a cooling unit or heat pump that compresses refrigerant gas so it can absorb heat.

Concrete
A basic building and paving material made by mixing water with sand, gravel, and cement.

Concrete block
A hollow or solid unit made of concrete used in building construction.

Condensing unit
The outdoor segment of a cooling system. It includes a compressor and condensing coil designed to give off heat.

Conduit
A metal tube used to run, house or contain electrical wire.

Convection
Currents created by heating air, which then rises and pulls cooler air behind it.

COP
(coefficient of performance). A measure of the efficiency of any heating unit--arrived at by dividing its output in BTUs by its input in BTUs.

Coping
A cap at the top of a wall that's rounded or beveled to shed water. Also, a curved cut made so that one contoured molding can join neatly with another.

Corner bead
Lightweight, perforated metal angle used to reinforce outside corners in drywall construction.

Corner assembly
The framing members used to change direction in an interior-exterior wall.

Corner brace
Diagonal supports set into studs to reinforce the area where a wall changes direction in a frame structure. In many areas plywood is used.

Cornice
The projection from a building that crowns or finishes the edge. Horizontal projection at the top of exterior wall which finishes the eaves of a building.

Courses
Parallel layers of building materials such as bricks, shingles, or siding laid up horizontally.

Cove
A concave curve where vertical and horizontal surfaces join.

Crawl space
Space between floor and ground of a house or building.

Cripples
Short studs above or below a door or window opening.

Crown
Paving slightly humped so that water will run off. Also a contoured molding sometimes installed at the junctures of walls and ceilings.

Cupping
A type of warping that causes boards to curl up at their edges.

Damper
A valve inside a duct or flue that can be used to slow or stop the flow of air or smoke.

Dampproofing
The coating applied to the exterior of a foundation wall with a waterproofing material such as foundation coating.

Dead bolt
A locking device that can be activated only with a key or thumb turn. Unlike a latch which has a beveled tongue, dead bolts have square ends.

Decking
The material installed over the supporting framing members to which the roofing material is applied.

Directional Light
Light intensity at the center of the beam. Used for flood and spot light bulbs types.

Do-it-yourself
(DIY). The process of doing any project by oneself. Some may traditionally have been contracted out to a professional or in the case of a klutz done by one's spouse or father-in-law. If necessity is the mother of invention it is also the father of DIY.

Double cylinder
A type of lock that must be operated with a key from inside as well as outside.

Double hung window
A window that has a top sash and bottom sash, both of which move up and down.

Double pane window
Two panes of glass sealed at the edges to create dead air space. The sealed air acts as an insulator.

Drain tile
A perforated, corrugated plastic pipe laid at the bottom of the foundation wall used to drain excess water away from the foundation. It prevents water from seeping through the foundation wall.

Drying in
The construction process generally considered to be from the foundation plate up through the application of exterior finish materials.

Dry wall
A masonry wall laid up without mortar.

Drywall
A basic interior building material consisting of big sheets of pressed gypsum faced with heavy paper on both sides. Also known as gypsum board, plasterboard, and SheetrockTM.

DWV
(drain-waste-vent). The section of a plumbing system that carries water and sewer gases out of a home.

EER
(energy efficiency ratio). A measure of cooling efficiency computer by dividing a cooling unit's output in BTUs by its input in watts.

EPACT
Energy Policy Act. Government regulations promoting the use of energy efficient lighting by prohibiting the manufacturing or importing of certain inefficient bulb types.

Efflorescence
A whitish powder sometimes exuded by the mortar joints in masonry work. It's caused by salts rising to the surface.

Elbow
(ell). A plumbing or electrical fitting that lets you change directions in runs of pipe or conduit.

Evaporator coil
The part of a cooling system that absorbs heat from air in your home.

Expansion joint
Flexible material between two surfaces that enables joints to ride out differing rates of expansion and contraction.

Facing brick
The brick used and exposed on the outside of a wall. Usually these have a finished texture.

Fascia board
Horizontal trim attached to the outside ends of rafters or to the top of an exterior wall.

Felt or Felt Paper
Highly absorbent fiber material saturated and impregnated with asphalt and used as backing for rock surfaced roofing materials. Made from organic, asbestos or glass fibers to result in a strong, absorbent and flexible product.

Female
Any part, such as a nut or fitting, into which another (male) part can be inserted. Internal threads are female.

Finger joint
A manufacturing process of interlocking two shorter pieces of wood end to end to create a longer piece of dimensional lumber or molding. Often used in jambs and casings.

Finish roof
Shingles, asphalt, etc. used to cover the exterior of a roof.

Fire brick
Brick made of refractory ceramic material which will resist high temperatures. Used in a fireplace.

Fire blocking
Short horizontal members sometimes nailed between studs, usually about halfway up a wall.

Firebrick
Highly heat-resistant brick for lining fireplaces and boilers.

Flashing
Metal or composition strips used to seal junctions between roofing and other surfaces, or in the valleys between different slopes.

Floating
The next-to-last stage in concrete work, when you smooth off the job and bring water to the surface.

Floor girder (girder)
A horizontal beam supporting the floor joists.

Floor joist
One of a series of parallel framing members used to support floor loads and supported in turn by larger beams, girders, bearing walls or foundation.

Flue
A pipe or other channel that carries off smoke and combustion gasses to the outside air.

Fluorescent lamp
A light source that instead of "burning" as incandescent bulbs do, uses an ionization process to produce ultraviolet radiation. This turns into visible light when it hits a coating on the tube's inner surface.

Footing
The base on which a masonry wall rests. It spreads out the load to prevent settling.

Framing
The wood skeleton of a building.

Framing in
The construction process generally considered to be from the foundation plate up to the application of exterior finish materials.

Frost line
The depth to which the ground freezes below the surface. This varies from region to region, and determines how deep footings must be.

Furring
Lightweight wood or metal strips that even up a wall or ceiling for paneling or drywall. On masonry, furring provides a surface on which to nail.

Fuse
A safety device designed to burn out if a circuit shorts or overloads. This protects against fire.

Gable
The triangular end of an exterior wall above the eaves of a pitched roof.

Gable roof
A roof which slopes from two sides only.

Gable stud
The stud at the gable of a roof where the exterior finish is applied.

Gang nail plate
A steel plate attached to both sides at each joint of a truss.

Gate valve
A valve that lets you completely stop--but not modulate--the flow within a pipe.

GFCI
(ground fault circuit interrupter). An electrical safety device that instantly shuts down a circuit if a leakage occurs. Codes commonly require them on bathroom and outdoor circuits.

Girder (floor girder)
A horizontal beam supporting the floor joists.

Glazing
The process of installing glass, which commonly is secured with glazier's points and glazing compound.

Globe valve
A valve that lets you adjust the flow of water to any rate between fully on and fully off.

Grade
Ground level, or the elevation at any given point.

Grain
The direction of fibers in lumber or other materials.

Ground
Refers to electricity's habit of seeking the shortest route to earth. Neutral wires carry it there in all circuits. An additional grounding wire--or the sheathing of metal-clad cable or conduit--protects against shock if the neutral leg is interrupted.

Grout
Thin mortar that fills the joints between tiles or other masonry.

Gypsum board
A basic interior building material consisting of big sheets of pressed gypsum faced with heavy paper on both sides. Also known as drywall, plasterboard, and SheetrockTM.

Hardboard
A manufactured building material made by pressing wood fibers into sheet goods.

Header
Heavier framing--usually doubled and laid on edge-- at the top of a window, door, or other opening. In masonry, a header course of bricks or stones laid on edge provides strength.

Heat gain
Heat coming into a home from sources other than its heating/cooling system. Most gains come from the sun.

Heat loss
Heat escaping from a home usually to outside air. Heat gains and losses are expressed in BTUs per hour.

Heat pump
A reversible air conditioner that can extract heat from outside as well as inside air.

HID
(high intensity discharge) lamp. A lamp that operates in the same way as a fluorescent tube, but that has a bulb like incandescent lamps.

Hip roof
A roof with four sloping sides.

Hot wire
The wire that carries electrical energy to a receptacle or other device--in contrast to a neutral,which carries electricity away again.

Incandescent lamp
A lamp employing an electrically charged metal filament that glows at white heat.

Inside corner
The point at which two walls form an internal angle, as in the corner of a room.

Interior finish
Any coverings that cover the interior walls of a house. Examples are drywall, paneling, etc.

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.

Jambs
The top and sides of a door, window, or other opening. Includes studs as well as the frame and trim.

Joint compound
A synthetic-based formula used in combination with paper tape to conceal joints between drywall panels.

Joists
Horizontal framing members that support a floor and/or ceiling.

Kilowatt
(kw). One thousand watts. A kilowatt hour is the base unit used in measuring electrical consumption.

Laminating
Bonding together two or more layers of materials.

Latch
A beveled metal tongue operated by a spring-loaded knob or lever. The tongue's bevel lets you close the door and engage the locking mechanism, if any, without using a key.

Lath
Strips of wood, expanded metal mesh, or a special drywall that serve as a base for plaster or stucco.

Level
True horizontal. Also a tool used to determine level.

Life
The average number of hours a bulb will burn.

Lighting Efficiency
Expressed as Lumens per Watt. A measure of efficiency similar to miles per gallon. The best choice is usually the highest light output Lumens for the least power consumed (Watts).

Limit switch
A safety control that automatically shuts off a furnace if it gets too hot. Most also control blower cycles.

Lineal foot
A unit of measure for lumber equal to any thickness by any width by 12 inches long. Example:
2" x 12" x 12' = 12 lineal feet
1" x 12" x 12' = 12 lineal feet

Lintel
A load bearing beam over an opening in masonry, such as a door or fireplace.

Lumens
Unit of measure for total light output.

Male
Any part, such as a bolt, designed to fit into another (female) part. External threads are male.

Masonry
Brick, tile, stone, concrete units, etc., or combinations thereof, bonded with mortar. Something constructed using bricks or stones.

Millwork
Woodwork such as doors, sashes and trim that have been shaped, usually by a milling machine.

Miter
A joint formed by beveling the edges or ends of two pieces at 45-degree angles, then fitting them together to make a 90-degree angle.

Mortar
The bonding agent between bricks, blocks, or other masonry units. Consists of water, sand, and cement--but not gravel.

Mortise
A hole, slot, groove, or other recess into which another element fits. Most hinges, for example, are mortised so they lie flush.

Muriatic acid
Commonly used as a brick cleaner after masonry work is completed.

NEC
(National Electrical Code). A set of rules governing safe wiring methods. Local codes(which are backed by law) may differ from the NEC in some ways.

Neutral wire
Usually color-coded white, this carries electricity from an outlet back to ground.

Newel post
A post at the bottom, landing, or top of a staircase to which the handrail is secured.

No-hub
A clamp-and-sleeve system for joining together cast-iron drainage pipes. Older hub-type pipes had to be leaded at all joints.

OC
(on-center). The distance from the center of one regularly spaced framing member to the next. Studs and joists are commonly 16 or 24 inches OC.

Outside corner
The point at which two walls form an external angle, one you usually can walk around.

Overhang
Outward projecting eave-soffit area of a roof; the part of the roof that hangs out or over the outside wall.

Panel
Wood, glass, plastic, or other material set into a frame, such as in a door. Also, a large, flat, rectangular building material such as plywood, hardboard, or drywall.

Partition
An interior dividing wall. Partitions may or may not be bearing.

Paving
Materials (commonly asphalt or masonry) laid down to make a firm, even surface.

Payback
The length of time before the money you save with new equipment, insulation, etc. will equal your original investment. Commonly used in evaluating energy-related items.

Pier
A masonry post. Piers often serve as footings for wood or steel posts.

Pilot hole
A small-diameter hole that guides a nail or screw.

Pilot light
A small, continuous flame that ignites gas or oil burners when needed.

Pitch (roof)
The slope of a roof expressed in feet rise per foot of run. Example a pitch of 5/12 means that the roof raises 5 feet for every 12 feet of run.

Plenum
The main hot-air supply duct leading from a furnace.

Plumb
True vertical.

Plumb bob
A lead weight attached to a string. It is the tool used in determining plumb.

Plywood
A building panel made by gluing together thin layers of wood. Alternating grain directions from one layer to the next adds strength.

Post
Any vertical support member.

Post-and-beam
A basic building method that uses just a few hefty posts and beams to support an entire structure. Contrasts with stud framing.

Pressure-treated wood
Lumber that has been saturated with a preservative.

Primer
A first coating formulated to seal raw surfaces and hold succeeding finish coats.

PVC
(polyvinyl chloride). A type of plastic pipe that's suitable for cold water, but not hot.

Radiation
Energy transmitted from a heat source to the air around it. So-called ``radiators" actually depend more on convection than radiation.

Rafters
Parallel framing members that support a roof.

Rail
Any relatively lightweight horizontal element, especially those found in fences. Also the horizontal pieces between panels in a panel door.

Retaining wall
A structure that holds back a slope and prevents erosion.

Ridge board
The topmost beam at the peak of a roof to which rafters tie.

Rise
The vertical distance from one point to another above it; a measurement you need in planning a stairway or ramp.

Riser
The upright piece between two stairsteps.

Roof decking
Subsurface material on which roof shingles or built up roofing is applied. Some roof decking is made with one side finished to serve as both roof deck and finished ceiling.

Roof sheathing
The sheets or boards for sheathing over rafters. Also called roof decking, roof underlayment.

Roofing cement
A pliable asphalt- or plastic-based compound used as an adhesive and to seal flashings, minor leaks, etc.

Rough opening
The openings in walls and partitions for doors and windows as formed by the framing members.

Rough sill
The framing member at the bottom of a rough opening for a window. It is attached to the cripple studs below the rough opening.

Roughing-in
The initial stage of a plumbing, electrical, carpentry, or other project, when all components that won't be seen after the second finishing phase are assembled.

Run
The horizontal distance a ramp or stairway traverses.

R-value
A measure of the resistance an insulating material offers to heat transfer. The higher the R-value, the more effective the insulation.

Saddle
The plate at the bottom of some--usually exterior--door openings. Sometimes called a threshold.

Sash
The openable part of a window, consisting of a frame and one or more panes of glass.

Setback
The distance a home must be built from property lines (this is dictated by local zoning ordinances. Also a temporary change in a thermostat's setting.

Settlement
Shifts in a structure, usually caused by freeze-thaw cycles underground.

Sheathing
The first covering on a roof or exterior wall, usually fastened directly to rafters or studs.

SheetrockTM
A type of wall and ceiling finish made from ground gypsum covered with a paper finish. Common sizes are 4'x8', 4'x12'. Most commonly used as a wall finish that is then painted or wallpapered. Also, drywall, gypsum wall board.

Shim
Thin material inserted to make adjustments in level or plumb. Tapered wood shingles make excellent shims in carpentry work.

Shingle
A covering used to finish the sides or the roof of a house.

Shoe molding
Strips of quarter round commonly used where a baseboard meets the floor. Also sometimes known as base shoe.

Short circuit
A situation that occurs when hot and neutral wires come in contact with each other. Fuses and circuit breakers protect against fire that could result from a short.

Siding
The finish material of an exterior wall. Types include wood, aluminum, vinyl and hardboard.

Sill
The lowest horizontal piece of window, door, or wall framework.

Sill plate
(mudsill). Bottom horizontal member of an exterior wall frame which rests atop foundation, sometimes called mudsill. Also sole plate, bottom member of interior wall frame.

Slab
(concrete). A term referring to a flat area of concrete.

Slab construction
A build term referring to construction placed on a slab as its foundation.

Sleepers
Boards laid directly over a masonry floor to serve as nailers for plywood, or strip or plank flooring.

Soffit
Covering attached to the underside of eaves or a staircase.

Soil pipe
A large pipe that carries liquid and solid wastes to a sewer or septic tank.

Sole plate
The bottommost horizontal part of a stud partition. When a plate rests on a foundation, it's called a sill plate.

Spacing
The distance between individual members or shingles in building construction.

Span
The distance between supports, generally walls, for rafters or trusses.

Spandrel
The space between two openings which are one above the other in a wall.

Spec home
A house built before it is sold. The builder speculates that he can sell it at a profit. Sometimes he speculates that he can merely sell it.

Specifications
Written elaboration in specific detail about construction materials and methods; this supplements working drawings.

Square
A situation that exists when two elements are at right angles to each other. Also a tool for checking this. An area of roofing which is 10' square or comprising 100 square feet.

Stick built
A house built without prefabricated parts. Also called conventional building.

Stile
The vertical upright on either side (and sometimes the center) of a panel door.

Stringer
The side or inclined member of a stair system used to support the treads and risers.

Stops
Moldings along the inner edges of a door or window frame. Also valves used to shut off water to a fixture.

Strike
The plate on a door frame that engages a latch or dead bolt.

Stucco
A mixture of Portland cement, sand, lime and water used to cover cement blocks for decoration purposes.

Stud framing
A building method that distributes structural loads to each of a series of relatively lightweight studs. Contrasts with post-and-beam.

Studs
Vertical 2x3, 2x4, or 2x6 framing members spaced at regular intervals within a wall.

Subfloor
Bottom layer of plywood or boards in a two-layer floor.

Take off
A list of materials developed from a set of blueprints.

Taping
The process of covering drywall joints with paper tape and joint compound.

T or Tee
A T-shaped plumbing fitting.

Terra Cotta
A ceramic material molded into masonry units.

Three-four-five triangle
An easy, mathematical way to check whether a large angle is square. Measure three feet along one side, four feet along the other; if the corner is square, the diagonal distance between those two points will equal five feet.

Threshold
The plate at the bottom of some--usually exterior--door openings. Sometimes called a saddle.

Throat
The opening at the top of a fireplace through which smoke passes enroute to the flue.

Tie
(veneer). A metal strip used to tie a brick or masonry wall to the wooden frame wall.

Toe-nail
To drive nails at an angle.

Ton
A measure of cooling power. One ton equals 12,000 BTU's.

Tongue and groove
A style of lumber in which the pieces interlock to form a strong solid formation.

Top chord
The upper or top member of a truss.

Top plate
The topmost horizontal element of a stud-frame wall.

Trap
A plumbing fitting that holds water to prevent air, gas, and vermin from backing up into a fixture.

Treads
The level parts of a staircase.

Treated lumber
A chemical treatment applied to dimension lumber to prevent rot or decay. Examples are Wolmanized, salt treatment, penta wood. Used mainly in outdoor decks and other exposed areas.

Trimmers
Studs at either side of a door, window, or other opening that are used to support the header.

Truss
A prefabricated structure made of wood members designed to form a rigid framework for supporting loads over a given span.

Trusses
Pre-engineered and wood frames designed to support roof or floor loads.

UL
(Underwriters' Laboratories). An independent testing agency that checks electrical and other components for possible safety hazards.

Underlayment
Top layer of plywood (or other material) in a two-layer floor. Provides a smooth base for carpet, tile or sheet flooring.

Union
A plumbing fitting that joins pipes end-to-end so they can be dismantled.

Valley
The intersection of two roof slopes.

Vapor barrier
A waterproof membrane in a floor, wall, or ceiling that blocks the transfer of condensation.

Volt
(V). A measure of electrical pressure. Volts x amps = watts.

Warping
Any distortion in a material.

Watt
(W). A measure of the power an electrical device consumes. Watt hours (WH) express the quantity of energy consumed.

Wye or Y
A Y-shaped plumbing fitting.

There were no terms beginning with that letter.

Y or Wye
A Y-shaped plumbing fitting.

Zoning
Ordinances regulating the ways in which a property may be used in any given neighborhood. Zoning laws may limit where you can locate a structure.