Building Term Glossary

Building Term Glossary

A partial listing of terminology common to the housing industry.

Air Space

A cavity or space in walls or other enclosed parts of a building between various structural members.
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Anchor Bolt

A bolt used for securing structural steel or wood to masonry or concrete. The bolt is placed in the concrete while the concrete is being poured or into the masonry while the brickwork is being placed.
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Angle Brace

A support used to stiffen a frame, placed across a corner at an angle to the supported members.
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Asphalt

A mineral pitch insoluble in water and used extensively in building for water-proofing, roof coverings, in the manufacture of shingles, floor tiles and in paints.
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A.S.T.M.

Stands for the "American Society for Testing Materials." A group dedicated to the standardization of building materials specifications and performance requirements.
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Astragal

A semicircular or convex molding used to cover a joint between paired doors which are hung in a single opening. It serves as a door-stop for the initial swing door, when nailed to the second door.
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Back cut

A groove cut into the back side of a molding or finished flooring so that it will lay flat on the surface to which it is applied.
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Balloon

Pertains to a particular type of house framing characterized by the studs extending in one piece from the foundation sill to the roof plate. It is not widely used because it requires applied fire blocks and a let-in band or ribbon for the second floor joists.
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Balusters

Small pillars supporting a hand rail. More commonly known as banister spindles.
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Bargeboard

The finished board covering the gable rafter on a gable roof after the siding has been applied.
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Baseboard

Interior trim used on the wall at the floor line.
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Batten

A narrow strip of wood placed over the vertical joint between pieces of sheathing or paneling.
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Batter Board

A combination of two boards supported by stakes. A "working line" (string) is stretched between two batterboards and tradespeople use the line for reference points.
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Bay Window

A window in a panel that projects out beyond the rest of the wall surface.
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Beam

A horizontal member of wood, metal or concrete which supports the floor joists, or the floor slab. The beam is supported by either walls or columns. Beams that support other beams are called girders.
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Beam Pocket

An opening left in a wall in which the end of a beam will rest.
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Bearing Wall

A wall which supports all or part of the floors, roofs or ceilings in a building; a partition that carries the floor joists and other partitions above it.
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Bed Joint

A horizontal mortar joint in brick or other masonry walls. The vertical joists and other partitions are above it.
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Bench Mark (B.M.)

A basis for computing elevations by means of identification marks or symbols on stone, metal or other durable matter, permanently fixed in the ground, and from which differences of elevations are measured. Also referred to as a datum point.
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Bevel Siding

Boards used for enclosing a structure. They are thicker at one edge than at the other. Thus, the boards are beveled.
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Blind Nailing

A method of fastening flooring in which the nail is driven into the edge of the board just above the tongue at an angle so that the head is concealed by the edge of the next board. Sometimes called secret nailing.
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Board Foot

The ordinary measure of lumber. A board foot of lumber is a piece of lumber that measures one inch in thickness and is 12" square.
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Board and Batten

See "Batten". A type of exterior siding, usually applied vertically, which consists of a series of wide boards whose adjoining edges are covered by narrow strips of boards called battens. Used for many historical agricultural storage buildings or barns.
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Brick Veneer

A type of construction in which a wood frame or steel structural frame has an exterior surface of brick applied as non-load bearing cladding.
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Bridging

A method of bracing floor joists to distribute the weight of applied loads over the entire frame. Generally, two small pieces of 1x3 wood stock or narrow galvanized metal strips are used in criss-cross fashion between the joists. If the bracing is accomplished by using the same size stock as the joists or studs that it braces, it is referred to as solid bridging.
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Building Line

A line marked out by surveyors and used by craftsmen for a guide line. The surveyors get their information from the plans and specifications. The building line is generally located, or marked, on batterboards or on stakes placed about six feet outside the corner of the building.
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Building Permit

A certificate that must be obtained from local code enforcement agency by the property owner or contractor before a building can be erected, modified or repaired and which must be kept posted in a conspicuous place until the job is completed and passed by the building inspector.
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Caisson

A deep foundation form often used to build footings for large buildings, bridges, etc. Two basic types:

  1. The open caisson is a deep hole open at the top and supported on the side by wood or metal piling or bracing.
  2. The compressed air caisson is a closed chamber in which compressed air is used to help hold back surrounding water and mud.

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Camber

A slight arching of a timber, or beam; given to prevent the member from sagging due to its own weight or the load it must carry.
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Cantilever

A projecting beam supported at one end and at another point along its length and extending out into the air at its other end, also referred to as a lookout.
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Capillary Break

A specific material application intended to prevent or radically slow the transmission of moisture from one plane to another.
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Casing

Finished trim work connecting a jamb to a wall, typically around a window or door.
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Caulk

May refer to a method or material. A method of weatherproofing joints between different materials by filling, or covering, the joint with a mastic compound of various materials including silicone, latex, modified bitumens, etc. It is generally necessary to caulk around door and window frames.
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Center to Center

Refers to measurements taken from the center of one member to the center of another member, as in the spacing of joists, studs or other structural parts. "On-center" spacing comes from this practice.
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Chamfer

Refers to a corner beveled at an angle.
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Chord

Either of the two outside members of a truss connected and braced by the web members.
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Cleat

A strip of wood nailed to a wall, frame, or deck for the purpose of supporting, often temporarily, some object fastened to it.
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Collar Tie

A horizontal beam used in roof construction to tie or connect a pair of opposing rafters and to transfer and offset loads from one to the other; usually installed at a level considerably above the wall plates.
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Column

A vertical member which may function decoratively or as a structural support.
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Concrete Slump Test

A test to determine the plasticity of concrete. A sample of wet concrete is placed in a cone-shaped container twelve inches high. When the container is one-third full, the sample is rodded or tamped twenty-five times. This rodding process is repeated at the two-thirds stage and when the container is completely full. Thirty seconds after the last rodding the cone is removed by slowly pulling it upward. The concrete will now "slump" because it is not supported. The amount of slump is then measured.
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Coped Joint

The seam, or juncture, between molded pieces in which a portion of one piece is cut away to receive and house the profile of the other piece.
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Corbel

A course (or piece) of wood or masonry that projects out beyond the course below it. It is sometimes used entirely for decoration but it can also be used as a ledge to support a weight that projects beyond the wall line.
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Corner Bead

A metal strip used to protect plaster and drywall at corners.
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Corner Brace

Diagonal blocking or let-in braces form a triangular shape to make the frame rigid and solid.
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Cost-plus

A type of contract between the owner and a contractor. When a contractor takes a job at cost-plus, it means that the owner must pay him the actual cost of all the material and labor used plus a definite profit on a percentage basis.
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Crawl Space

A space beneath a house or other structure that lacks a basement which allows access to utilities, etc.
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Cricket

A small roof structure, single or double sloped, that is usually used with a flat roof in such a manner as to divert drainage toward a downspout.
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Cubic Yard

A measure of volume that is three feet wide, three feet high and three feet deep. 3 x 3 x 3 = 27, therefore there are 27 cubic feet in a cubic yard.
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Dampproof

A layer of tar or other material impervious to moisture and used to prevent moisture from passing through it. Also referred to as a capillary break.
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Deadening Sound

The use of insulating materials to reduce sound transmission through a structure.
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Detail

A term in architecture applied to the small parts into which any structure is divided. It is applied generally to drawings showing a special feature of construction.
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Dormer

A framed structure projecting above a sloping roof surface. Normally contains a vertical window unit.
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Douglas Fir

A soft lumber produced from Oregon Fir trees. Considered a premium framing material.
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Downspout

Any (typically vertical or near vertical) connector for carrying water from the roof of a building to the ground.
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Drip Cap

A molding trim of wood placed over the outside window and door frames to shed water away from the wall.
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Dry Rot

A decay of seasoned wood. This decay is due to a lack of air circulation which permits a fungus growth to develop and reduces wood to a fine powder.
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Eaves

The projecting lower edges of a roof overhanging the walls of a building.
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Elevation

The level or height of an object. In surveying, the elevation of an object indicates its height compared to the height of another object.
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Expansion

A joint in walls or floors to take up expansion due to temperature changes.
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Facia

A board used in cornice construction. It may be a frieze or it may be the board that is nailed to the ends of the lookouts.
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Fiberglass

Glass that has been spun into fine threads. The threads are made into a batting which is used as an insulating material.
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Fire-Retarding Material

Any material that will smolder but will not burn rapidly unless subjected to intense heat. Insulation board would be in this class.
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Fire-stop

Any material that is placed so that it will prevent the rapid spread of fire. It is used to block the passage of flames or air currents upward or through a building.
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Flitch

A plate, usually of steel, used to reinforce a wood beam.
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Float

The process of smoothing wet concrete, pushing down the aggregate and bringing the paste to the top.
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Flush Door

A door having two flat faces (no panels). It is frequently of hollow core construction.
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Footing

The lowest part of a structure. It is generally of concrete spread out flat to distribute the weight of the building over the greatest possible area.
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Form

The framing built of either wood or metal for "forming" the concrete.
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Foundation

The supporting portion of a structure below the first-floor construction or grade, including the footings.
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Frost Line

The level below the natural grade at which freezing occurs.
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Furring

To build a separate wall attached to the primary structure.
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Gable

The end wall of a building where the roof slopes on only two sides. The gable is that triangular shaped part of the wall between the two eaves and that ridge.
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Grade

The lay of the land. Typically the top of the earth against and around a building.
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Grade Stake

A stake or series of stakes put in the ground to establish a known, uniform or consistent horizontal plane.
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Gusset Plate

A structural steel or plywood plate used in a truss to reinforce the connection of the tie, chord and strut.
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Gypsum Board

A wallboard made of a mineral, hydrous sulfate of calcium, and covered with paper; also referred to as drywall or sheetrock.
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Hangar

A stirrup-like drop support attached to a wall to carry the end of a beam or joist.
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Header

A supporting member extending between two joists or studs and used for supporting superimposed loads in a floor or a wall.
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Head Room

The vertical space in a doorway; also the clear space in height between a stair tread and the ceiling or stairs above.
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High Chair

A heavy wire device used to support reinforcing steel.
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Horse

One of the slanting supports of a set of steps to which the treads and risers of a stair are attached; also called the carriage.
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Insulation

Materials used in building construction for the reduction of fire hazard or for protection from heat or cold. Also used for noise reduction.
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Jamb

The lining of a rough opening for the installation of a door or window.
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Joint

In masonry, the operation of applying mortar between courses.
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Joist

A horizontal beam used with others as a support for a floor, ceiling or roof, and identified as a floor joist, ceiling joist or roof joist.
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Kerf

The cut of a saw made on a board, the width of which is controlled by the set of the teeth in the saw.
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Kiln Dried

A marking by which wood is artificially seasoned in an oven-like chamber, hastening the drying process.
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Knot

A defect which weakens lumber.
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Lally Column

A round cast iron or steel pipe used as a column; sometimes filled with concrete.
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Laminate

To form with sheets or plates.
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Landing

The small platform between two flights of stairs which run between the floors of a building.
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Lead Wall

Refers to a portion of a foundation wall intended to transfer loading from a later shallower footing addition (a porch, patio, garage, etc.) to the original foundation footing.
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Ledger

A board which is nailed to studding for floor joists; also called a ribbon strip.
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Level

A tool used to determine a level plane or line or a surveyor's instrument.
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Live Load

A reference to the load imposed on a structure by its intended use. Includes furnishings and people.
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Lookout

A short horizontal framing piece typically attached to studs at one end and to the lower end of a rafter at the other. Used to support finish soffit materials.
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Louver

An opening in a wall used for the passage of air.
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MAHB

Michigan Association of Home Builders. Group of Industry advocates.
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Masonite

A hard composition board usually about 1/4" thickness manufactured by Masonite Corporation
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Mineral Wool

A type of bat insulation which consists of many fine threads of a wood by-product. It is also used for fireproofing and for acoustical treatment.
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Modular

Pre-engineered, pre-built housing components. Applied in various degrees of completion.
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Molding

A strip of material cut to serve as an ornament or trim.
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Mullion

In windows it is the vertical member between adjoining sash frames.
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Muntin

The (typically) wood members in a window sash that separate individual pieces of glass.
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NAHB

National Association of Home Builders. Group of Industry advocates.
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Nonbearing Wall

A term used in the building trade when referring to a wall which defines space but does not carry overhead loads from partitions, floors or roofs.
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Nosing

The leading edge of a stair tread that projects over the riser.
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OSB

Oriented Strand Board - a formed panel, typically in widths of 4' and thickness' ranging from 7/16" to 1", structural or non, consisting of layers of compressed strand like pieces of wood bonded at right angles to each other.
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Overhang

Formed by extending the rafters or rafter tails beyond the vertical wall line.
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Panelized

Refers to engineered, pre-built wall, roof or foundation components.
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Penny

A term used to indicate nail length. It originally meant the price paid for 100 nails. For example, ten penny nails were those that cost 10 pennies per 100. The letter "d" is the symbol for penny.
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Performance Guidelines

Written workmanship specifications for construction usually adapted to building contracts. Such specifications may determine acceptable standards plumb, square, level, true, joint tolerances, levels of finish, etc.
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Pitch

A reference to the rise/run combination that determines roof slope.
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Pilaster

A vertical thickening in a wall intended to give it additional resistance to shear loads.
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Pile Caps

Reinforced concrete footings designed to bear on the tops of pilings. See "Piling".
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Piling

A piece of a foundation support system used in unstable or "weak" bearing soils. Piles may be driven, bored, jetted, or cast into place. Two primary types are friction piles and direct load bearing.
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Plancier

The underside of an eave, soffit or cornice.
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Plinth Block

A small block slightly thicker and wider than the casing for interior trim of a door.
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Plumb

Absolutely vertical (straight up and down).
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Point Load

A concentrated load, typically as imposed by a load bearing column or post.
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Post and Beam

A type of construction made with load-bearing posts and beams in which the enclosing walls are designed to support no loads other than their own weight.
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Precast

The shaping of a structural member, typically concrete, prior to its being placed in a building.
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Prefabricated

A type of construction so designed as to involve a minimum of assembly at the site, usually comprising a series of large engineered wood panels or precast concrete units manufactured in a plant. Precut wood stock to exact dimensions either at mill, yard or jobsite prior to using.
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Purlins

Horizontal roof framing members that overlay the rafters to help support finish roofing materials.
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Quarter Round

A molding with a cross section equal to 1/4 of a full circle. Typically used against floor base.
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R-Value

A numerical reference to an insulating material's resistance to heat transfer.
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Rafter

A structural roof framing component that runs from top plate to supporting ridge, beam, hip or other member. Typically spaced from 12"-24" on center.
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Rake

Trim member that finishes the joint between roof and vertical wall at a gable end.
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Reinforced Concrete

Concrete in which steel is used to reinforce its tensile strength.
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Reinforcing Rods, Steel

Steel reinforcing bars that are deformed with little projecting edges to ensure that they will not pull out of concrete. They are sized by diameter in increments of 1/8" with a 1/8" bar referred to as a number 1, a 1/4" bar, a number 2, etc.
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Reveal

The margin to which casing is set to the jamb for appearance and to accommodate the door butts.
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Retaining Wall

A wall used to hold back various elevations of earth. Usually on a drained footing reinforced with parallel whalers and perpendicular "dead men".
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Ridge

The top of a roof perpendicular to the run of the rafters.
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Ridge Beam

The horizontal wood framing member at the peak of a roof to which the top of opposing rafters are connected.
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Riser

In a stair, the upright piece which connects successive stair treads and "closes" the stair. Stairs can also be built with open risers.
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Rod

A reinforcing steel bar, also referred to as a rebar.
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Roof Types

Flat, gable, hip, gambrel, mansard, shed and butterfly.
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Roll Roofs

Reference to "flat" roofing process where successive layers of felt paper are installed as a watershed and covered with stone ballast to prevent uplift. Some applications involve the addition of hot tar or asphalt between each layer.
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Roughing In

The process of assembling the supporting frame of a structure.
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Rough Opening

The framework of a window or door which has been sized to accept the finished unit.
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Sash

The framework which hold the glass in a window.
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Scuttle

A hole which affords entrance to a crawl space or attic.
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Select Lumber

Lumber without knots or other deformities.
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Sheath

To cover rough framework with composition board, rigid foam or other materials.
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Siding

The placing of boards over the outside wall of a frame building.
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Sill

The lowest part of a wood frame. Also the lowest part of an opening in a wall such as a door sill or window sill.
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Snap Tie

A patented wire wall tie for concrete wall forms. It is so made that the end of the wire may be twisted or snapped off after the forms have been removed.
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Soffit

The underside of an overhang.
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Span

The distance between the two supports of a structure on which a horizontal member rests.
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Specifications

The written matter supporting the building plans which identify specific components, materials and methods to be used.
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Spirit Level

Leveling devices, usually hand held, that use a small sealed glass tube filled with alcohol or glycerin and a small air bubble.
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Square

Designates 100 square feet and is used as a unit of measurement for roofing and siding. Also a reference to a layout tool used in construction.
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Stair Well

A compartment extending vertically through a building in which stairs are built.
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Staking Out

A term used for the laying out of a building plan by driving stakes into the ground showing the location of the foundation or "footprint" of the proposed building.
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Story Pole

A rod or pole used for layout cut to the proposed clear height between two vertical points. Most often used by masons to determine and monitor the thickness of horizontal mortar joints needed to accommodate a certain number of full brick courses.
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Strike Plate

In building, the part of a door latch system fastened to the jamb which is "struck" by (and catches) the latch bolt when the door is closed.
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Stud

In building a vertical framing member, usually a piece of dimension lumber, 2" x 4" or 2" x 6" which runs between sole plate and top plate.
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Subcontractor

A company (or individual) who enters into an agreement with a general contractor to furnish labor/material to a job.
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Subfloor

In carpentry, a term applied to a flooring of rough boards or plywood laid directly on the floor joists and serving as a walking surface during the process of construction on the building.
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Toenail

To drive a nail at an approximate 45 degree angle from plumb.
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Trim

The finished woodwork of a structure.
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Trimmer

A reinforcing beam or stud into which a header is framed for a stairway, door or window opening.
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Truss

Structural steel or wood members fastened together to make a framework which will span long distances. Components are webbing, chords, and gussets.
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Valley

A depression in a roof where two parts of a roof at different slopes come together.
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Vapor Barrier

Any material which is used to retard the passage of vapor or moisture.
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V-Joint

A joint between two pieces of wood or other materials.
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Vermiculite

Used as a bulk insulation, often as a loose fill in hollow core masonry. Also used in acoustical plasters and wet spray finishes.
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Wainscot

The lower section of a wall that is of different material than the rest of the wall.
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Waterproof

To render a material impervious to water.
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Weather Strip

A strip of material covering joints around doors and windows.
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Weep Hole

A small hole, as in a retaining wall, to drain water to the outside.
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Weep Chord

A string like material used to plug the weep hole while allowing moisture to migrate to the outside.
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Zero Clearance

Indicates there is no requirement or tolerance between two adjoining members or units; a reference to any of a number of pre-fabricated fire burning units designed to be installed in close proximity to wood framing materials.
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