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Homeowner's Glossary of  Building Terms United States Department of Housing and Urban  Development

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

This publication defines some terms used in home construction, repair and maintenance. It is not a comprehensive list but will provide a quick reference for homeowners who are unfamiliar with building terminology.

A

Acoustical Tile Special tile for walls and ceilings made of mineral, wood, vegetable fibers, cork, or metal. Its purpose is to control sound volume, while providing cover. Air Duct Pipes that carry warm air and cold air to rooms and back to  furnace or air conditioning system. Ampere The rate of flow of electricity through electric wires. Apron A paved area, such as the juncture of a driveway with the  street or with a garage entrance.

B

Backfill The gravel or earth replaced in the space around a building  wall after foundations are in place. Balusters Upright supports of a balustrade rail. Balustrade A row of balusters topped by a rail, edging a balcony or a staircase. Baseboard A board along the floor against walls and partitions to hid  gaps. Batt Insulation in the form of a blanket, rather than loose filling. Batten Small thin strips covering joints between wider boards on  exterior building surfaces. Beam One of the principal horizontal wood or steel members of a building. Bearing Wall A wall that supports a floor or roof of a  building. Bib or Bibcock A water faucet to which a hose may be attached, also called  a hose bib or sill cock. Bleeding Seeping of resin or gum from lumber. This term is also used  in referring to the process of drawing air from water  pipes. Brace A piece of wood or other material used to form a triangle  and stiffen some part of a structure. Braced Framing Construction technique using posts and cross-bracing for greater rigidity. Brick Veneer Brick used as the outer surface of a framed  wall. Bridging Small wood or metal pieces placed diagonally between floor joists. Building Paper Heavy paper used in walls or roofs to  dampproof. Built-Up Roof A roofing material applied in sealed, waterproof layers, where there is only a slight slope to the roof. Butt Joint Joining point of two pieces of wood or molding. Bx Cable Electricity cable wrapped in rubber with a flexible steel  outer covering.

C

Cantilever A projecting beam or joist, not supported at one end, used to support an extension of a structure. Carriage The member which supports the steps or treads of a stair. Casement A window sash that opens on hinges at the vertical edge. Casing Door and window framing. Cavity Wall A hollow wall formed by firmly linked masonry walls, providing an insulating air space between. Chimney Cap Concrete capping around the top of chimney bricks and  around the floors to protect the masonry from the elements. Chair Rail Wooden molding on a wall around a room at the level of a chair back. Chamfered Edge Molding with pared-off corners. Chase A groove in a masonry wall or through a floor to accommodate pipes or ducts. Chimney Breast The horizontal projection-usually inside a building-of a chimney from the wall in which it is built. Circuit Breaker A safety device which opens (breaks) an electric circuit automatically when it becomes overloaded. Cistern A tank to catch and store rain water. Clapboard A long thin board, thicker on one edge, overlapped and nailed on for exterior siding. Collar Beam A horizontal beam fastened above the lower ends of rafters to add rigidity. Coping Tile or brick used to cap or cover the top of a masonry  wall. Corbel A horizontal projection from a wall, forming a ledge or  supporting a structure above it. Corner Bead A strip of wood or metal for protecting the external corners of plastered walls. Cornice Horizontal projection at the top of a wall or under the  overhanging part of the roof. Course A horizontal row of bricks, cinder blocks or other masonry materials. Cove Lighting Concealed light sources behind a cornice or horizontal recess which direct the light upon a reflecting ceiling. Crawl Space A shallow, unfinished space beneath the first floor of a house which has no basement, used for visual inspection and access to pipes and ducts. Also, a shallow space in the attic, immediately under the  roof. Cripples Cut-off framing members above and below  windows.

D

Door Buck The rough frame of a door. Dormer The projecting frame of a recess in a sloping  roof. Double Glazing An insulating window pane formed of two thicknesses of glass with a sealed air space between them. Double Hung Windows Windows with an upperand lower sash, each supported by cords and weights. Downspout Leader Downspout A spout or pipe to carry rain water down from a  roof or gutters. Cripples A pipe for conducting rainwater from the roof to a cistern or to the ground by way of a downspout. Downspout Strap A piece of metal which secures the downspout to the eaves  or wall of a building. Drip The projecting part of a cornice which sheds rain  water. Dry Wall A wall surface of plasterboard or material other than  plaster.

E

Eaves The extension of roof beyond house walls. Efflorescence White powder that forms on the surface of  brick. Effluent Treated sewage from a septic tank or sewage treatment  plant.

F

Fascia A flat horizontal member of a cornice placed in a vertical position. Fill-Type Insulation Loose insulating material which is applied by hand or blown  into wall spaces mechanically. Flashing Noncorrosive metal used around angles or junctions in roofs  and exterior walls to prevent leaks. Floor Joists Framing pieces which rest on outer foundation walls and  interior beams or girders. Flue A passageway in a chimney for conveying smoke, gases or  fumes to the outside air. Footing Concrete base on which a foundation  sits. Foundation Lower parts of walls on which the structure is built.  Foundation walls of masonry or concrete are mainly below ground level. Framing The rough lumber of a house-joists, studs, rafters, and  beams. Furring Thin wood, or metal applied to a wall to level the surface for lathing, boarding, or plastering, to create an insulating air space, and to  damp proof the wall. Fuse A short plug in an electric panel box which opens (breaks) an electrical circuit when it becomes  overloaded.

G

Gable The triangular part of a wall under the inverted "v" of the  roof line. Gambrel Roof A roof with two pitches, designed to provide more space on upper floors. The roof is steeper on its lower slope and flatter toward the  ridge. Girder A main member in a framed floor supporting the joists which  carry the flooring boards. It carries the weight of a floor or  partition. Glazing Fitting glass into windows or doors. Grade Line The point at which the ground rests against the foundation wall. Green Lumber Lumber which has been inadequately dried and which tends to  warp or "bleed" resin. Grounds Pieces of wood embedded in plaster of walls to which skirtings are attached. Also wood pieces used to stop the plaster work around doors and windows. Gusset A brace or bracket used to strengthen a  structure. Gutter A channel at the eaves for conveying away rain water.

H

Hardwood The close-grained wood from broad-leaved trees such as oak or maple. Headers Double wood pieces supporting joists in a floor or double  wood members placed on edge over windows and doors to transfer the roof and floor weight to the studs. Heel The end of a rafter that rests on the wall plate. Hip Roof A roof that slants upward on three or four sides. Hip The external angle formed by the juncture of two slopes of a roof.

J

Jalousies Windows with movable, horizontal glass slats angled to admit-ventilation and keep out rain. This term is also used for outside shutters  of wood constructed in this way. Jamb An upright surface that lines an opening for a door or window. Joist A small rectangular sectional member arranged parallel from  wall to wall in a building, or resting on beams or girders. They support a floor or the laths or furring strips of a  ceiling.

K

Kiln-Dried Artificial drying of lumber, superior to most lumber that  is air dried. King-Post The middle post of a truss. Large, heavy screws, used where  great strength is required, as in heavy framing or when attaching ironwork to  wood.

L

Lag-Screws or Coach-Screws Large, heavy screws, used where great strength is required,  as in heavy framing or when attaching ironwork to wood. Lally Column A steel tube sometimes filled with concrete, used to support girders or other floor beams. Lath One of a number of thin narrow strips of wood nailed to  rafters, ceiling joists, wall studs, etc. to make a groundwork or key for  slates, tiles, or plastering. Leaching Bed Tiles in the trenches carrying treated wastes from septic  tanks. Ledger A piece of wood which is attached to a beam to support joists. Lintel The top piece over a door or window which supports walls above the opening. Load-Bearing Wall A strong wall capable of supporting  weight. Louver An opening with horizontal slats to permit passage of air, but excluding rain, sunlight and view.

M

Masonry Walls built by a mason, using brick, stone, tile or similar  materials. Molding A strip of decorative material having a plane or curved  narrow surface prepared for ornamental application. These strips are often used  to hide gaps at wall junctures. Moisture Barrier Treated paper or metal that retards or bars water vapor, used to keep moisture from passing into walls or floors. Mullion Slender framing which divides the lights or panes of windows.

N

Newel The upright post or the upright formed by the inner or smaller ends of steps about which steps of a circular staircase wind. In a straight flight staircase, the principal post at the foot or the secondary post at a landing. Nosing The rounded edge of a stair  tread.

P

Parging A rough coat of mortar applied over a masonry wall as  protection or finish; may also serve as a base for an asphaltic waterproofing compound below grade. Pilaster A projection or the foundation wall used to support a floor  girder or stiffen the wall. Pitch The angle of slope of a roof. Plasterboard (See Dry  Wall) Gypsum board, used instead of plaster. Plates Pieces of wood placed on wall surfaces as fastening  devices. The bottom member of the wall is the sole plate and the top member is the rafter plate. Plenum A chamber which can serve as a distribution area for heating or cooling systems, generally between a false ceiling and the actual ceiling. Pointing Treatment of joints in masonry by filling with mortar to improve appearance or protect against weather. Post-And-Beam  Construction Wall construction in which beams are supported by heavy  posts rather than many smaller studs. Prefabrication Construction of components such as walls, trusses, or  doors, before delivery to the building site.

R

Rabbet A groove cut in a board to receive another board. Radiant Heat Coils of electricity, hot water or steam pipes embedded in floors, ceilings, or walls to heat rooms. Rafter One of a series of structural roof members spanning from an  exterior wall to a center ridge beam or ridge board. Reinforced Concrete Concrete strengthened with wire or metal bars. Ridge Pole A thick longitudinal plank to which the ridge rafters of a roof are attached. Riser The upright piece of a stair step, from tread to tread. Roof Sheathing Sheets, usually of plywood, which are nailed to the top  edges of trusses or rafters to tie the roof together and support the roofing  material.

S

Sandwich Panel A panel with plastic, paper, or other material enclosed  between two layers of a different material. Sash The movable part of a window-the frame in which panes of glass are set in a window or door. Scotia A concave molding. Scuttle Hole A small opening either to the attic, to the crawl space or to the plumbing pipes. Seepage Pit A sewage disposal system composed of a septic tank and a connected cesspool. Septic Tank A sewage settling tank in which part of the sewage is  converted into gas and sludge before the remaining waste is discharged by  gravity into a leaching bed underground. Shakes Handcut wood shingles. Sheathing (See Wall Sheathing) The first covering of boards or material on the outside  wall or roof prior to installing the finished siding or roof  covering. Shim Thin tapered piece of wood used for leveling or tightening a stair or other building element. Shingles Pieces of wood, asbestos or other material used as an  overlapping outer covering on walls or roofs. Shiplap Boards with rabbeted edges overlapping. Shiplap Siding Boards of special design nailed horizontally to vertical studs with or without intervening sheathing to form the exposed surface  of outside walls of frame buildings. Sill Plate The lowest member of the house framing resting on top of the foundation wall. Also called the mud sill. Skirtings Narrow boards around the margin of a floor;  baseboards. Slab Concrete floor placed directly on earth or a gravel base and usually about four inches thick. Sleeper Strip of wood laid over concrete floor to which the  finished wood floor is nailed or glued. Soffit The visible underwide of structural members such as  staircases, cornices, beams, a roof overhang or eave. Softwood Easily worked wood or wood from a conebearing  tree. Soil Stack Vertical plumbing pipe for waste water. Stringer A long, horizontal member which connects uprights in a frame or supports a floor or the like. One of the enclosed sides of a stair supporting the treads and risers. Studs In wall framing, the vertical members to which horizontal  pieces are nailed. Studs are spaced either 16 inches or 24 inches apart. Subfloor Usually, plywood sheets that are nailed directly to the  floor joists and that receive the finish flooring. Sump A pit in the basement in which water collects to be pumped out with a sump pump. Swale A wide shallow depression in the ground to form a channel  for storm water drainage.

T

Tie A wood member which binds a pair of principal rafters at the bottom. Tile Field Open-joint drain tiles laid to distribute septic tank  effluent over an absorption area or to provide subsoil drainage in wet  areas. Toenail Driving nails at an angle into corners or other  joints. Tongue-And-Groove Carpentry joint in which the jutting edge of one board fits  into the grooved end of a similar board. Trap A bend in a water pipe to hold water so gases will not escape from the plumbing system into the house. Tread The horizontal part of a stair step. Truss A combination of structural members usually arranged in  triangular units to form a rigid framework for spanning between load-bearing  walls.

V

Valley The depression at the meeting point of two roof  slopes. Vapor Barrier Material such as paper, metal or paint which is used to  prevent vapor from passing from rooms into the outside  walls. Venetian Window A window with one large fixed central pane and smaller panes at each side. Vent Pipe A pipe which allows gas to escape from plumbing  systems. Verge The edge of tiles, slates or shingles, projecting over the gable of a roof.

W

Wainscoting The lower three or four feet of an interior wall when lined  with paneling, tile or other material different from the rest of the  wall. Wall Sheathing Sheets of plywood, gypsum board, or other material nailed  to the outside face of studs as a base for exterior siding. Weather Stripping Metal, wood, plastic or other material installed around  door and window openings to prevent air infiltration. Weep Hole A small hole in a wall which permits water to drain  off.

U.S. Department of Housing and Urban Development 451 Seventh Street SW Washington DC 20410 July 1996