A

AEROSOL - A suspension of fine particles, solid or liquid, in a gas.

AIR BARRIER - A material installed within a building envelope assembly to minimize the uncontrolled passage of air into and out of a building.

AIR FILM - The layer of air next to a surface which offers some resistance to heat flow.

ANGLE OF INCIDENCE - The angle that the sun's rays make with a line perpendicular to a surface. The angle of incidence determines the percentage of direct light intercepted by a surface.

ATTIC - The space between the top floor ceiling and the roof.

AWNING - A shading device mounted on the outside of a window.

B

BASEBOARD - A molded board placed against the wall around a room next to the floor to conceal the joint between the floor and wall finish.

BASEMENT - The lowest story of a building, below or partly below ground level.

BATTEN - A narrow strip of wood used to cover joints between boards or panels.

BEAM - A main horizontal structural member, supported at two or more points.

BEAM POCKET - A notch formed at the top of a wall to receive and support the end of a beam.

BEVEL - The sloping surface formed when two surfaces meet at an angle that is not a right angle.

BOARD - A piece of lumber sawed thin, with considerable length and breadth compared with the thickness.

C

CASEMENT WINDOW - A window frame made to turn and open on hinges.

CASING - The molded trim used around window and door openings.

CAULKING - The practice of sealing a joint.

COLUMN - A vertical free-standing body, generally serving as a support to something resting on its top.

CONDENSATION - The transformation of the vapor content of the air into water on cold surfaces.

CONDUCTION - The transfer or travel of heat through a body by molecular action.

CONVECTION - The transfer of heat by the movement of a fluid such as air.

D

DENSITY - The mass of a substance in a unit volume.

DOOR JAMB - The surrounding case into and out of which a door opens and closes.

DOUBLE GLAZING - Two panes of glass in a window with an air space between the panes.

DRYWALL - Interior wall made of gypsum or other materials instead of plaster.

DUCTS - Pipes used to carry heated and cooled air to and from rooms.

E

EAVE - The section of the roof that overhangs the exterior wall.

END MATCHED - A board having grooved ends.

EXPANSION JOINT - A joint used to provide for expansion and contraction of materials due mostly to changes in moisture content and temperature.

F

FASCIA - A vertical board nailed to the ends of rafters that forms the face of the eave.

FIRE STOP - Members installed inside walls and floors to keep fire from spreading.

FLASHING - A material used in roof and wall construction to keep water from leaking in.

FLUE - A pipe in a chimney through which gases and smoke pass.

FOOTING - A concrete pad upon which the foundation is set.

FURRING - The wood strips fastened to the walls and ceiling to form a straight surface for applying finished wall material.

G

GABLE - The triangle area of an exterior wall at the end of a house from the top plate to the rafters.

GIRDER - A horizontal structural member used to support walls and floor joists.

GUSSETT - A plywood or metal plate used to join the members of a truss and to add strength at each joint.

GYPSUM BOARD - Sheet material having a gypsum core laminated between layers of heavy paper.

H

HARDBOARD - Sheet material made by bonding wood fibers.

HEADER - A horizontal supporting member that spans an opening in a frame wall.

HIP RAFTER - A diagonal rafter that runs from the ridge to the corner intersection of the top plates of two walls.

HIP ROOF - A roof with four sides sloping away from the ridge.

I

IMPERMEABLE - Not permitting water vapor or other fluid to pass through.

INSULATION - Materials used to stop or inhibit the passage of heat. Most often used in walls, ceilings, and floors.

INTERIOR TRIM - All the interior woodwork design to conceal joints.

J

JAMB - The lining of a door or window opening.

JOIST - A horizontal structural member used to support a floor or ceiling.

K

KNEE WALL - A short wall used in construction of the second floor of a one-and-one-half-story house.

L

LANDING - A platform at the top or bottom of a flight of stairs.

LEDGER - A wood strip nailed to the side of a wood beam and used to support joists meeting the beam.

LINTEL - A horizontal structural member that supports the load over an opening such as a door or window.

LOOKOUT - A horizontal framing member that supports a roof overhang.

LUMBER - Any wood that has been sawed and planed.

M

MASONRY - Units made of concrete, stone, cement, brick, or tile.

MOLDING - Machined strips used for interior and exterior decoration.

MORTAR - A mixture of cement, sand, and water, used to bond masonry units together.

MULLION - A vertical member separating multiple windows or doors.

MUNTIN - Small bars between the panes of glass in a window.

N

NOMINAL SIZE - The size of lumber after it has been cut at the sawmill but before it has been planed smooth.

NON-BEARING WALL - A wall that carries no loads other than its own weight.

O

ORIENTATION - Positioning of a building to take advantage of the sun, wind, and view.

OVERHANG - The horizontal distance between the fascia and the exterior wall.

P

PARAPET - The part of an exterior wall that extends above the edge of the roof.

PARTITION - An interior wall.

PERMEABLE - Permitting water vapor or other fluid to pass through.

PITCH - The angle of the roof from the ridge board to the plate.

PLUMB - Being absolutely vertical.

PLYWOOD - Wood sheets made by gluing thin layers together with the grain in each layer at 90 degrees to the previous layer.

R

RAFTERS - Structural members used for supporting the roof sheathing and the outer layers of the roof.

REINFORCING - The practice of placing steel rods or metal fabric in concrete to increase the strength.

R-VALUE - The measure of resistance to heat flow.

S

SASH - The movable frame of a window, containing the glass panes.

SHAKE - A shingle split from a block of wood and used for roofing and siding.

SHINGLES - Any small pieces of asphalt, wood, tile, slate or other material used to weatherproof a roof or the exterior of a wall.

SIDING - The finish material forming the outside layer of an exterior wall.

SOFFITT - The horizontal part of the eave.

SPAN - The distance between two supporting members.

STILE - The vertical edge of a door or window.

STORM WINDOW - An extra window usually placed on the outside of an existing one as additional protection against cold weather.

STUCCO - A cement mixture used as an exterior covering on buildings.

STUD - Vertical wood or metal units used in wall construction.

T

THERMOSTAT - A device that regulates air temperature in a building by controlling the heating and air-conditioning unit.

TONGUE-AND-GROOVE CONSTRUCTION - Machined projection on one board (tongue) that corresponds to groove on another board.

TRUSS - An assembled unit used for roof construction that includes rafters, ceiling joists, and necessary bracing.

U

UNDERLAYMENT - Floor covering used to provide a level surface for finish floor coverings such as carpet.

V

VALLEY - The intersection of two sloping roof sections.

VAPOR BARRIER - A material that prevents the passage of moisture through walls and floors.

VENT - An opening that allows a flow of air.

W

WEATHERSTRIPPING - A strip of felt, rubber, metal or other material, fixed along the edges of doors or windows to keep out drafts and reduce heat loss.