COMMON CONSTRUCTION TERMINOLOGY
APEX - Same as PEAK
ATTIC SCUTTLE- Framed opening with removable cover providing access to the attic.
ASPHALT SHINGLES - A type of composition shingles made of felt saturated with asphalt and surfaced with mineral granules.
ASPHALT SATURATED FELT - used as an underlayment material in roofing.
AUGER - A wood-boring tool used by a carpenter to bore holes
BALLOON FRAMING - 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.
BEAM - any large piece of timber, stone, iron or other structural material used to support a load over an opening or from post to post.
BEARING -A structural support, usually a beam or wall that is designed by the building designer to carry truss reaction loads to the foundation.
BENDING MOMENT -Term used in the analysis of the internal stresses across the cross section of a member (chord or web) when it is subjected to forces which cause it to bend.
BIRDS MOUTH CUT -A long notch at the ends of a member to allow for an overhang "over the wall height" less than the width of the member.
BOARD FOOT - The equivalent of a board 1 foot square and 1 inch thick.
BOTTOM CHORD -An inclined or horizontal member that establishes the bottom of a truss. An example of an inclined bottom chord member is the bottom chord of a scissors truss or a truss positioned between supports at different elevations.
BOTTOM CHORD BEARING - Term usually used to describe the bearing condition of a parallel chord truss that bears on its bottom chord.
BRACING - Ties & rods used for supporting and strengthening various part Of a building Used for lateral stability for columns and beams.
BRIDGING -Wood or metal members that are placed between trusses and joists in an angled position intended to spread the loads.
BEVEL - angle cut on truss member to allow a better fit after installation
BLOCKING - The process of fastening together two pieces of board by gluing blocks of wood in the interior angle.
BUILDING DESIGNER -Registered architect or registered engineer who is responsible for the design of the building.
BUILDING OFFICIALS AND CODE ADMINISTRATORS INTERNATIONAL (BOCA) -A model building code located in Country Club Hills, IL, serving primarily the North Central and Northeast United States.
BUILT-UP ROOFING - used on a flat roof, several layers of felt mopped with hot tar or asphalt finished with mineral rock or top coating.
CUT -Slight vertical cut at outside edge of truss bottom chord to ensure
uniform nominal span and tight joints.
BUTT JOINT - The interface at which the ends of two members or other members meet in a square cut joint.
CABINETS - Upper cabinets are 30" high and 12" deep and lower cabinets are 36" high and 24" deep.
CAD -Computer aided design and drafting (software).
CAMBER - An upward curvature built into a truss bottom chord to compensate for deflection due to loading conditions.
CANTILEVER - is a beam that extends beyond its support , exclusive of overhang.
CAP SHEET - a finish saturated roofing felt used as a covering for a roof.
CENTER LINE SPAN -Theoretical span sometimes used to design trusses.
SPAN -(Clear Opening) Generally indicates the inside or interior
frame to frame dimensions. Not to be confused with SPAN.
NAIL -A nail selected to be longer than the member it is driven
through and which is bent back the dimension of its excess length.
CLIPPED (CLIPPED END) -Same as stubbed or stub truss.
COLLAR BEAM - A tie that keeps the roof from spreading. Connects similar rafters on opposite sides of roof.
COLLAR TIE -A horizontal member placed between two rafters a specific vertical distance above the very top plate line for the purpose of limiting outward thrust of the rafters.
COMPOSITE LUMBER -(Structural, wood composites) A family of materials that contain wood in whole or fiber form bound together with an adhesive of natural or synthetic form.
CUT -A double cut made across the member width.
DOCUMENTS - Architectural drawings (plans), specifications, etc., used
to produce a structure.
CONVENTIONAL FRAMING - (Common Framing) Framing with conventional joists, rafters and wall studs.
COURSE - horizontal continuous row of shingles running the length of a roof.
-Time-dependent deformation of a structural member under constant load.
CRICKET - A ridge or drainage diverting roof framing. Generally found on the high sloped end of a chimney.
CUTTING SHEETS -A diagram of lumber lengths and angles of cut for truss web members and chords.
CUTTING BILL -See CUTTINGSHEETS.
DEAD LOAD - The weight of structural parts of a building and other fixed loads.
DIRECT NAIL -To nail perpendicular to the member being nailed.
DORMER - a window unit projecting through the sloping plane of a roof.
"DROPPING" A STRINGER - means cutting short on the bottom of a stairs, to allow for thickness of the first tread.
DRYWALL -Interior finish material sheet manufactured with gypsum (gypsum board).
DUB - To cut off the corners of shingles at the valleys.
EAVE - the edge of a roof projecting over the outside wall of the house.
EDGE, DRIP - A continuous corrosion-resistant, non-staining material such as 26 gauge galvanized steel, formed to provide a drip and nailed along the eaves and rakes. They are designed and installed to protect the edges of the deck and prevent leaks at this point by allowing water to drip free of underlying eave and cornice construction.
EXPOSURE - The shortest distance in inches between exposed edges of overlapping courses of roofing; the amount left exposed to the weather.
END LAP or SIDELAP - The shortest distance in inches which adjacent shingles horizontally overlap each other.
-The flat surface located at the outer end of a roof overhang or cantilever
CUT -A heel cut which has been made with a zero butt cut (a sawn member
with a feathered edge).
FIREPLACE TRUSS -A truss which has a modified shape to allow for penetration of a roof chimney whose loads are supported by a fireplace master (girder) truss. This truss requires special engineering.
FINISH GRADE - Any surface which has been cut to or built to the elevation indicated for that point. Surface elevation of lawn, driveway or other improved surfaces after completion of grading operations.
FLASHING - material, usually metal, used to prevent seepage of wind & water at any roof intersection or projection such as vent pipes, valleys, chimneys, dormers etc. Flashing is done before applying the shingles.
GABLE END FRAME -A component manufactured to the profile of the mating common truss. It has vertical "in-plane" members fastened to the chords instead of diagonal web members. It is not a structural truss and requires continuous support by a bearing wail or other load bearing element such as a beam along the bottom chord.
GABLE END TRUSS -Same as GABLEENDFRAME.
GABLE - The portion of the roof above the eaves line of a double sloped roof.
GAMBREL - A roof having two slopes on each side, the lower slope usually steeper than the upper one.
GALVANIZED DRIP EDGE - A drip edge made of galvanized metal applied under the felt at the eaves or over the felt at the rake or to the sheathing. see DRIP EDGE
GIRDER - A main beam upon which floor joists rest.
GIRDER TRUSS -A truss designed to carry heavy loads from other structural members framing into it. Usually a multiple ply truss.
GLAZING - The placing of glass in windows, doors, and mirrors.
GLAZED, DOUBLE - Windows that have 2 panels of glass separated by an air space and sealed around the edges. Used to prevent additional heat loss.
GLASS, TEMPERED - A special process which glass goes through to strengthen it. Tempering involves heating the glass and then chilling it suddenly. The minimum clearance from the floor should be 18".
GLASS, PLATE - A polished high-grade glass cast in the form of a plate or sheet, used principally in high priced structures. A sheet of glass usually thicker and of a better quality than ordinary window glass with a smoother surface free from blemishes.
GLASS, TINTED - The addition of special ingredients to a basic glass batch will result in tinted glass. Made to reduce
GRADE OF ROOFING - Grade A, B, & C are approved fire rating roofs.
GUTTER - A trough that gathers rainwater from a roof and sends it down the downspout.
HEADER - A horizontal piece of wood over an opening such as a window or door, to support the walls immediately above the opening. See also “Lintel”
HEEL JOINT -The point on the truss where the top and bottom chords intersect.
HIP MASTER -Hip girder truss designed to carry prefabricated roof jacks or common framing and hip corners.
HIP - extends from the outside angle of the plate towards the apex of the roof. They are 2" deeper or wider than common.
ICBO -See INTERNATIONAL CONGRESS OF Building CODE OFFICIALS and MODEL BUILDING CODE.
INSULATION - Material used to make a building more energy efficient and is located in roofs, walls and floors. They are classified according to form: (1) loose fill (2) flexible (3) rigid (4) reflective and (5) foamed-in-place. All types we rated according to their ability to resist heat flow (R-Value)
INTERIOR BEARING -Term used to describe supports which are interior to two exterior supports.
INTERNATIONAL CONGRESS OF BUILDING CODE OFFICIALS (ICBO) -A MODEL BUILDING CODE located in Whittier, CA, and serving primarily states West of the Mississippi.
JAMB - A side piece or post of an opening, sometimes applied to the door frame, or window.
JIG -The fixture which holds the truss in position until rigidly fastened with connectors.
JOINT -See PANEL POINT.
JOIST - parallel beams usually 2" thick used to support floors and ceilings and supported by larger beams, girders. Usually 2 x 10 or 2 x 12 spaced 16" apart.
KICKER -Alternate expression for a truss web member cantilever strut.
KNEE BRACE -A brace positioned between a column and truss panel points when trusses are supported by columns lacking transverse bracing.
LADDER PANEL -Prefabricated wall panel fastened to the roof eaves to create a sloped overhang.
LATERAL BRACING -Members placed and connected at right angles to a chord or web member of a truss.
LET TAILS RUN -When a piece of lumber making up the top chord is not cut off to a specified overhang length, but retains the length of the lumber used for the purpose of meeting specific overhang requirements in the field.
LEVEL RETURN -Lumber filler placed horizontally from the end of an overhang to the outside wall to form a soffit.
LINTEL - or header - A horizontal piece of wood over an opening such as a window or door. to support the walls immediately above the opening. Lintels can also be steel or stone.
LIVE LOAD - Weight on a structure consisting of movable objects & persons. On a flat roof, the minimum live load is 20 psf (pounds per square foot) if the roof is 200 square feet or less.
LVL -Laminated Veneer Lumber.
MAXIMUM OCCUPANCY LOAD - is the maximum number of people permitted in a room and is measured per foot for each width of exit door. The maximum is 50 per foot of exit.
MITER CUT -A single cut made at an angle to the member length.
MODEL BUILDING CODE (Model code) -Building codes sponsored by the three national organizations of local building code officials. See BUILDING OFFICIALS AND CODE ADMINISTRATORS INTERNATIONAL (BOCA), INTERNATIONAL CONGRESS OF BUILDING CODE OFFICIALS (ICBO) and SOUTHERN STANDARD BUILDING CODE CONGRESS INTERNATIONAL (SBCCI).
MOE -Modulus of Elasticity.
MOMENT -A force that produces rotation of a member and commensurate bending stresses.
MPCWT -Metal plate connected wood truss.
MSR -Machine stress rated lumber.
NAIL-ON PLATE -Light-gauge cold-formed steel truss connector plates with pre-punched holes or, if cut to size, without holes having identifying marks through which nails are driven by hand or pneumatic means into the lumber. They are usually located on the near face and far face of the joint.
NAILER (Scab) -A member fastened to another member by nails for reinforcement.
NATIONAL DESIGN SPECIFICATION (NDS) FOR WOOD CONSTRUCTION -Publication of the American Forest & Paper Association (AFPA) providing an appendix of lumber sizes, grades, species and allowable stresses.
NATIONAL DESIGN STANDARD FOR METAL PLATE CONNECTED WOOD TRUSS CONSTRUCTION -A publication of the Truss Plate Institute (TPI) being developed under the ANSI consensus process, to be designated as an ANSI/TPI standard.
NATIONAL EVALUATION REPORT (NER) -Product acceptance research evaluation report prepared for construction products that are not in the building code. This evaluation report is prepared by the model building code group under the Council of American Building Officials (CABO).
-See NATIONAL DESIGN SPECIFICATION FOR WOOD CONSTRUCTION.
NDSMPCWTC -See NATIONAL DESIGN SPECIFICATION FOR METAL PLATE CONNECTED WOOD TRUSS CONSTRUCTION.
NET FREE VENTILATED AREA -Area required by building codes to allow for proper ventilation in enclosed building spaces.
NOMINAL SPAN -Horizontal distance between outside edges of supports.
NOTCH -A vertical and crosswise horizontal cut at the end of the chord, joist or rafter.
O.C. - on center, studs, joists are placed so many inches on center, or inches apart.
ON EDGE -Vertical placement of a member's wide edge.
ON THE FLAT -Horizontal placement of a member's wide edge.
OUT-TO-OUT SPAN -Same as OVERALL SPAN.
OUTRIGGER -A wood member nailed to a truss to form an overhang beyond the wall line.
OVERALL SPAN -Outside of frame dimensions (not outside of veneer dimensions).
OVERHANG -The extension of the top chord of a truss beyond the outside of the bearing support.
PCT -Parallel chord trusses.
P. E.- Licensed registered professional engineer.
PANEL POINT -The location on a truss where the web members intersect the top and bottom chord.
PANEL -The chord segment defined by two adjacent joints.
PANEL LENGTH -The distance between joints measured along the chord center line.
PARAPET - a low wall installed around the outside edge of a flat roof, which serves as a protective railing.
PEAK -Point on the truss where the sloped chords meet.
PENNY -Common nail length. Originally, nails were sold by "penny weight", or price per hundred.
PIGGY BACK TRUSS -A truss made in two pieces usually consisting of a hip type truss with a triangular cap fastened to it. Designed when shipping or manufacturing limitations are affected by overall truss height.
PITCH – the angle of incline as a measurement is the ratio of the rise of roof to the span of the building. It indicates the incline of a roof as a ratio. The ratio of the vertical rise to the horizontal run (span). It is expressed as a fraction. For example if the rise of a roof is 4 ft. and the run is 12 ft., the roof is designated as having a pitch of 4/12.
PLACING DRAWING -Line drawing used to located assumed placement positions of roof and floor trusses by truss fabricator.
PLATE, SIL - A horizontal piece anchored to a masonry wall, usually of pressure treated lumber.
PLATE LINE - The top horizontal line of a building wall upon which the roof rests.
PLATE, SOLE - bottom horizontal member of a frame wall
PLATE, TOP - horizontal member of a frame wall, which all studs are nailed together by. See also “Very Top Plate”.
PLATE, DOUBLE - when two layers of 2 x 4's are placed on top of studs in framing a wall, this includes a “Top Plate” and a “Very Top Plate”.
PLUMB CUT -Top chord end cut to provide for vertical (plumb) installation of fascia.
PLUMBING STACK - The vertical pipe of a system of soil, waste or vent piping.
PLUMBING 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.
PLY - layer, for example a 2-ply roof would be two layers as in built-up roofing.Also, a member of a multiple "ply" girder truss.
POST & BEAM CONSTRUCTION - Most common type of wall framing, using posts which carry horizontal beams on which joists are supported. It allows for fewer bearing partitions, & less material.
-Purdue Plane Structures Analyzer. A wood structures computer program
developed at Purdue University. The latest edition is Version 4.
PRESS -A term used to describe the device used to embed truss connector plates.
PRESS-ON PLATE -A truss connector manufactured with pre-formed teeth that are embedded into the lumber usually by an air or hydraulic press.
PROFILE DRAWING -Sketches of truss profiles used by mechanical engineer to determine where mechanical ducts, piping, etc., are located.
PSL -Parallel strand lumber.
PURLIN -A horizontal member attached perpendicular to the truss top chord for support of the roofing (i .e., corrugated roofing or plywood and shingles).
R-VALUE - The higher the R value, the greater resistance to the flow of heat. R value requirements for walls and floors is R-11 insulation; for ceilings R-19 but when insulating an attic, in order to conform more often to State Energy requirements, R-30 should be used. R-11 used for floors, R-1 9 walls may be constructed by installing wall sheathing on the outside of 2x6 studs with R-11 between the studs.
RAFTER, COMMON - A rafter is a sloping roof member that supports the roof covering which extends from the ridge or the hip of the roof to the eaves. A common rafter is one which runs square with the plate and extends to the ridge.
RAKE -Edge of a roof with the intersection of the gable.
RAKE OVERHANG PANEL -Prefabricated overhang panel that extends over the edge of the roof and is fastened to the gable end truss.
REVIEW ENGINEER -Term used to define the truss engineer who checks and certifies computer generated designs of the truss fabricator. The review engineer may be an employee experienced in the design and testing of trusses, and assigned this responsibility by a truss plate manufacturer. He may also be an independent consultant experienced in the design and testing of metal plate connected trusses, and contracted by the truss fabricator to perform such services. Computer generated designs are assumed to be reviewed and checked on the review engineer's computer.
RIDGE VENT -A prefabricated and formed metal strip placed along the apex of the roof to allow exhaust ventilation in combination with intake soffit or gable end ventilation.
RISE -Vertical distance from the bottom of the bottom chord to bottom (inside) of the top chord.
RIDGE - is the top of a roof where two slopes meet, the highest point of a roof running the length of the building.
ROLLER PRESS -A press that embeds connector plates by forcing them through two opposing rollers.
ROOF SCUTTLE -Framed opening in commercial roofs surrounded by a hinged door used for access to a commercial roof.
SBCCI -See SOUTHERN BUILDING CODE CONGRESS INTERNATIONAL and MODEL BUILDING CODE.
SASH - The framework which holds the glass in a window
SCUPPER -Roof drain.
SET BACK -The distance from the outside edge of the wall exclusive of veneer to the face of a hip master (girder) truss.
SHEATHING - Plywood, gypsum or wood fiber encasing walls, ceilings, floors and roofs of framed buildings. It is the first layer of outer wall covering nailed to the studs or rafters.
SHORING - A temporary support erected in a trench or other excavation to support the walls from caving in.
SHOP DRAWING - Drawings of roof trusses prepared by the truss fabricator from truss engineering drawings used to fabricate trusses.
SHOULDER JOINT -Same as BREAK POINT JOINT.
SIDELAP - the distance asphalt shingles overlap horizontally. Also known as endlap.
SILL - The board laid first on the foundation upon which the frame rests. In a window or door, ft is the horizontal member laid directly at the bottom of the door or window frame to provide support and closure. Door sill keeps water out.
SLIDER -Two inch dimension lumber inserted between the top and bottom chords at the heel joint in the plane of the truss to reinforce the top or bottom chord.
SLOPE -The incline angle of the roof described in inches (or feet) of rise per inches (or feet) of run (e.g., 6/12).
SLOPED SOFFIT -Sloped overhang with no level return .
SOFFIT VENTS -Prefabricated soffit material with perforated openings created for the purpose of providing intake ventilation.
SOFFIT -The underside of a roof overhang or truss cantilever end.
SOFTWARE -Computer programs used to create management and engineering information, etc.
SOUTHERN BUILDING CODE CONGRESS INTERNATIONAL (SBCCI) -A model building code located in Birmingham, AL, and serving primarily the South Central and Southeastern United States.
SPAN - The entire horizontal distance to outside of structural supports or the width of a house.
SPLICE POINT -The point at which two chord members are joined together to form a single member. It may occur at a panel point or between panel points.
SQUARE - Roofing is estimated and sold by the square. A square of roofing is the amount required to cover 100 sq. feet of roof surface.
SQUARE CUT -End of top chord perpendicular to the slope of the member. Cut made at 90° to the length of the member.
STACKED CHORDS -Term used for agricultural trusses when two members are positioned on top of each other to create a bottom chord.
STRONGBACK -Two inch dimensional framing member attached perpendicular to floor trusses often through the chase opening and placed vertically against the vertical web.
STUB TRUSS -Same as BOBTAIL TRUSS.
STUD - One of a series of slender wood or metal vertical structural members placed as supporting elements in walls and partitions. Studs are usually 2 x 4, 2 x 6.
STUDDED GABLE -Terminology for a gable end truss built as a wall and resembling a stud wall built in the shape of a triangle. Chords are usually ON THE FLAT.
SUBSTRATE -The surface upon which the roofing membrane is placed.
T & G - Tongue & Grove - A type of flooring or sheathing where the tongue of one board is joined to the grove of another board
T-BRACE -A brace consisting of two inch dimension lumber nailed directly to the member requiring a brace, and with the width of the member perpendicular to the width of the brace.
TAB - the area of a shingle exposed to the weather, also called the BUTT.
THRUST -Term used to describe outward horizontal force.
TOENAIL -A nail driven at an angle to the member.
TOP CHORD BEARING -The bearing condition of a parallel chord truss that bears on its top chord extension. Can also apply to a sloping chord truss bearing on a top chord extension.
TOP LAP - The shortest distance in inches from the lower edge of an overlapping shingle to the upper edge of the lapped unit in the first course below, that is the width of the shingle minus the exposure.
TOP PLATE -Framing consisting of two members ON THE FLAT that form the top of exterior stud bearing walls of platform frame construction. A single member ON THE FLAT in non-bearing wall construction.
TOP CHORD -An inclined or horizontal member that establishes the top member of a truss.
-A conventionally framed wall usually consisting of fastened multiple
studs in a framed wall opening, used to carry the header reactions.
TRUSS -An engineered structural component, assembled from wood members, metal connector plates and other mechanical fasteners, designed to carry its own weight and super imposed design loads. The truss members form a semi-rigid structural framework and are assembled such that the members form triangles. Click [here] to view different types of Roof Trusses.
TRUSS ENGINEERING DRAWING -Drawing prepared by a registered professional engineer which prescribes truss geometry (span, slope, panel point locations, lumber, plate type, size and location, design loads, spacing, forces, etc.).
TRUSS MANUFACTURER (Truss Fabricator) -Producer of wooden trusses.
TRUSS SPACING -The on-center distance between trusses.
TYPES OF ROOFS - GABLE, FLAT, GAMBREL, DECK, MANSARD, SHED, BUTTERFLY. Click [here] to view different types of Roof Trusses.
VALLEY - extends from an inside angle of the plates toward the ridge of the house.
VALLEY TRUSS -Not a truss, but traditionally called so. A set of triangular components used to frame the shape of dormers and to complete the roof framing where trusses intersect at perpendicular corners. Valley members usually require support at a maximum distance of 24 inches.
VAPOR BARRIER - Material used to retard the passage of vapor or moisture through walls and thus prevent condensation (process of changing water vapor gas to a water liquid) within the walls. It is also called a moisture barrier and is installed between insulation and the interior wall.
VENT STACK - A vertical vent pipe installed for the purpose of providing circulation of air to and from any part of the drainage system.
VERY TOP PLATE (VTP) – Top most, horizontal member of a frame wall, which creates a solid connection between the top plates of adjacent walls.
VESTIBULE (Foyer) - entry section of a house. Minimum width should be 44"
MEMBER -Members that join the top and bottom chords to form the
triangular patterns typical of trusses. These members typically
carry axial forces.
WEDGE -A triangular piece of lumber that has one side equal to the standard two inch dimension lumber widths, and is inserted between the top and bottom chords, usually to allow the truss to cantilever. Its use is determined through engineering analysis.
WORKING DRAWINGS -Completed architectural drawings prepared by registered architect.
X-BRACE -Bracing which resembles the letter "X".
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