Construction Glossary: Essential Terms for Owner-Builders

Understanding construction terminology is critical for communicating with subcontractors, reading building codes, and navigating the permit process. This comprehensive glossary covers the most important terms you'll encounter as an owner-builder.

How to use this glossary

Terms are grouped alphabetically (A–Z), followed by sections for owner-builder and code/permitting vocabulary. Each table lists the Term and its definition. Use your browser’s find (Ctrl/Cmd-F) to jump straight to a word, and follow the related-resource links at the bottom to see these terms used in context.

A

A — construction terms
Term	Definition
ABS (Acrylonitrile Butadiene Styrene)	Black plastic pipe commonly used for drain-waste-vent (DWV) systems. Being replaced by PVC in many jurisdictions.
Actual Dimensions	The true size of lumber after planing and drying. A 2x4 actually measures 1.5" x 3.5". Compare to nominal dimensions.
AFCI (Arc Fault Circuit Interrupter)	Electrical device that detects dangerous arcing conditions and shuts off power. Required in bedrooms and most living areas by modern codes.
Aggregate	Sand, gravel, or crushed stone mixed with cement and water to make concrete. Size and quality affect concrete strength.
Air Barrier	Material layer that prevents air leakage through walls, improving energy efficiency. Often house wrap or specialized membranes.
Ampacity	Maximum current-carrying capacity of an electrical conductor, measured in amperes. Determines what size wire to use for each circuit.
Anchor Bolt	Steel bolt embedded in concrete foundation to secure sill plate and structure. Typically 1/2" diameter, 10" long, spaced 6' apart.
Apron	Decorative trim piece beneath a window sill on interior walls.
Ashlar	Pattern of masonry using rectangular stones of varying sizes laid in horizontal courses.
As-Built Drawings	Final set of construction plans showing all changes made during construction. Essential for future renovations.
Attic Ventilation	System of intake and exhaust vents that prevent moisture buildup and reduce cooling costs. Typically 1 square foot of vent per 150 square feet of attic.

B

B — construction terms
Term	Definition
Backfill	Soil or gravel placed against foundation walls after construction. Should be properly compacted in layers.
Backsplash	Protective wall surface behind sinks and counters, typically tile or stone.
Balloon Framing	Older framing method where wall studs run continuously from foundation to roof. Rarely used today; see platform framing.
Baluster	Vertical posts supporting a stair or deck railing. Spacing must prevent 4" sphere from passing through.
Barge Board	Decorative board covering roof rafters on a gable end. Also called verge board.
Batten	Narrow wood strip covering joints between wider boards in board-and-batten siding.
Batter Board	Temporary wooden frame used to mark building corners and maintain square during foundation layout.
Bay Window	Window that projects outward from wall, creating interior space. Requires special framing support.
Beam	Horizontal structural member supporting joists, rafters, or other loads. May be wood, steel, or engineered lumber.
Bearing Wall	Wall that supports structural loads from above. Cannot be removed without adding support beam.
Benchmark	Reference point of known elevation used for establishing site grades and foundation heights.
Bird's Mouth	Triangular notch cut in rafter where it sits on wall's top plate.
Blocking	Short pieces of lumber installed between joists or studs to provide backing, prevent twisting, or provide fire stops.
Blown Insulation	Loose fiberglass or cellulose insulation installed by blowing into attics or wall cavities.
Board Foot	Volume measurement for lumber: 1" thick x 12" wide x 12" long. Used for pricing rough lumber.
Bond	Pattern of masonry units (bricks or blocks). Common patterns: running bond, stack bond, Flemish bond.
Bond Beam	Horizontal reinforced concrete beam in masonry wall, typically at top of wall.
Bottom Plate	Horizontal framing member at bottom of wall, nailed to subfloor. Compare to top plate.
Box Sill	Platform framing method where joists sit on sill plate with rim joist around perimeter.
Bracing	Diagonal structural members preventing walls or frames from racking. Required by code in wind/seismic areas.
Brick Veneer	Single layer of brick applied to exterior of frame wall for appearance. Not structural.
Bridging	Diagonal or solid blocking between joists to distribute loads and prevent twisting.
BTU (British Thermal Unit)	Measure of heat energy. Used to rate heating/cooling equipment capacity.
Building Envelope	The physical separator between conditioned interior space and exterior. Includes walls, roof, foundation.
Building Paper	Asphalt-saturated felt paper used as moisture barrier. Being replaced by synthetic house wraps.
Bullnose	Rounded edge on drywall corner, stair tread, or countertop.
Butted Joint	Joint where two members meet end-to-end without overlapping.

C

C — construction terms
Term	Definition
Cant Strip	Beveled wood strip where roof meets wall, smoothing transition for roofing material.
Cantilever	Structural member extending beyond its support, like overhanging floor joists.
Casing	Decorative molding around door or window opening.
Caulk	Flexible sealant filling gaps to prevent air and water infiltration.
Cavity Wall	Masonry wall with air space between inner and outer layers, improving insulation.
Certificate of Occupancy (CO)	Official document stating building meets code and can be occupied. Required before moving in.
Chair	Small plastic or metal support holding rebar at proper height in concrete formwork.
Chase	Vertical shaft containing ducts, pipes, or wires. Must maintain fire rating of surrounding walls.
Circuit	Complete electrical path from panel through devices and back to panel.
Circuit Breaker	Safety device that opens circuit when overloaded or short-circuited. Resettable unlike fuses.
Cladding	Exterior covering of building: siding, brick, stucco, etc.
Clerestory	Window section above normal window height, typically at second story or above roofline.
Cleat	Strip of wood or metal fastened to surface to support another member.
CMU (Concrete Masonry Unit)	Standard concrete block, typically 8"x8"x16" nominal dimensions.
Collar Tie	Horizontal member connecting opposite rafters, typically in upper third of attic space.
Column	Vertical structural member supporting beams or roof loads.
Conditioned Space	Interior area that is heated and cooled. Affects insulation and vapor barrier requirements.
Conduit	Pipe or tube protecting electrical wiring. May be metal (EMT, rigid) or plastic (PVC, ENT).
Construction Documents	Complete set of drawings and specifications for building permit and construction.
Continuous Load	Electrical load expected to operate for 3+ hours, like lighting. Circuits must be sized at 125% of load.
Corbel	Decorative bracket projecting from wall to support shelf, mantle, or beam.
Corner Bead	Metal or plastic strip protecting outside drywall corners.
Cornice	Decorative assembly where roof overhangs wall, including fascia, soffit, and moldings.
Counterflashing	Upper piece of two-part flashing system, typically installed in masonry joints.
Course	Single horizontal layer of bricks, blocks, shingles, or siding.
Crawl Space	Shallow unfinished space between ground and first floor. Must be properly ventilated or sealed/conditioned.
Cricket	Small peaked saddle behind chimney or wall that diverts water. Also called saddle.
Cripple Stud	Short vertical framing member above header or below sill in wall framing.
Crown	Slight bow along length of lumber. Should be installed "crown up" in floor joists.
Curtain Wall	Non-structural exterior wall, typically glass and metal, hanging from building structure.

D

D — construction terms
Term	Definition
Damper	Adjustable plate in duct or flue controlling airflow.
Datum Point	Fixed reference point for measuring elevations on site. See benchmark.
Dead Load	Permanent static weight: structure, finishes, fixed equipment. Compare to live load.
Deadman	Buried anchor for retaining wall or guy wire.
Deck	Exterior floor platform, typically wood or composite material.
Deflection	Degree to which structural member bends under load. Code limits deflection to prevent damage.
Dew Point	Temperature at which water vapor condenses. Critical for vapor barrier placement.
Diaphragm	Structural element (floor or roof) that distributes lateral loads to shear walls.
Dimension Lumber	Framing lumber 2" to 4" thick and 2" to 16" wide (nominal dimensions).
Double-Hung Window	Window with two vertically sliding sashes, both operable.
Downspout	Vertical pipe carrying water from gutter to ground or drainage system.
Draft Stop	Material blocking concealed air passages to prevent fire spread. See fire blocking.
Drain Tile	Perforated pipe around foundation footer collecting and diverting groundwater.
Drip Cap	Molding placed above door or window to direct water away from opening.
Drip Edge	Metal strip at roof edge preventing water from running under shingles.
Drywall	Gypsum board interior wall and ceiling finish. Also called gypsum board, wallboard, or sheetrock.
Dry Well	Underground pit of gravel collecting roof runoff and allowing it to percolate into soil.
DWV (Drain-Waste-Vent)	Plumbing system carrying sewage and venting sewer gases outdoors.

E

E — construction terms
Term	Definition
Eave	Lower edge of roof overhanging wall.
Efflorescence	White crystalline deposit on masonry caused by water dissolving salts and evaporating.
Egress	Exit path from building. Bedrooms require egress window meeting size and height requirements.
Elbow	Plumbing or electrical fitting changing direction of pipe or conduit.
Elevation	Vertical height above reference point; or exterior drawing of building showing vertical face.
EMT (Electrical Metallic Tubing)	Thin-walled metal conduit for protecting electrical wires.
Energy Heel	Raised heel on roof truss allowing full-depth insulation at exterior wall. Also called raised-heel truss.
Engineered Lumber	Manufactured wood products: LVL, I-joists, glulam, etc. Stronger and more consistent than dimensional lumber.
Escutcheon	Decorative plate covering hole where pipe penetrates wall or floor.
Expansion Joint	Intentional gap in concrete or masonry allowing for thermal expansion/contraction.

F

F — construction terms
Term	Definition
Fascia	Vertical board at roof edge, typically where gutters attach.
Feeder	Electrical circuit supplying power to subpanel or large equipment.
Fenestration	Arrangement and design of windows in building.
Fill Sand	Clean sand used for backfilling or as leveling bed under slabs.
Finger Joint	Method of joining wood pieces end-to-end using interlocking "fingers" and adhesive.
Fire Blocking	Materials installed to prevent vertical air movement in walls that could spread fire.
Fire Rating	Time (in hours) material or assembly can withstand fire exposure. Required for certain walls and floors.
Firestop	Material preventing fire and smoke spread through penetrations in fire-rated assemblies.
Flashing	Thin metal or membrane preventing water intrusion at joints: roof valleys, chimneys, windows, doors.
Floating Floor	Floor finish not attached to subfloor, allowing for expansion/contraction. Common with laminate and engineered wood.
Floor Joist	Horizontal framing members supporting floor loads.
Flue	Passage in chimney conducting smoke and gases to atmosphere.
Fly Rafter	Rafter at gable end extending beyond supporting wall to form overhang.
Footing	Concrete base spreading load from foundation to soil. Sized based on soil bearing capacity.
Form	Temporary structure holding concrete in desired shape until it cures.
Foundation	Below-grade structural element supporting building. Types: slab, crawl space, basement.
Framing Plan	Construction drawing showing size and location of structural framing members.
Frost Line	Depth to which ground freezes. Footings must extend below frost line to prevent heaving.
Furring	Thin wood or metal strips attached to wall or ceiling to provide level surface or airspace.

G

G — construction terms
Term	Definition
Gable	Triangular section of wall at end of pitched roof.
Galvanized	Steel coated with zinc for corrosion protection. Common for nails, pipes, flashing.
Gambrel Roof	Roof with two slopes on each side, lower slope steeper than upper. Common on barns.
Gang	Multiple electrical boxes mounted together, like double or triple switch box.
General Contractor (GC)	Person coordinating all aspects of construction. As owner-builder, you perform this role.
GFCI (Ground Fault Circuit Interrupter)	Safety device detecting current imbalance and shutting off power. Required near water: bathrooms, kitchens, exterior.
Girder	Large horizontal beam supporting joists. May support entire floor section.
Glazing	Glass in windows and doors; or the process of installing glass.
Glulam (Glue-Laminated Timber)	Engineered lumber made from layers of dimensional lumber glued together. Used for beams and headers.
Grade	Ground level around building; or quality rating of lumber.
Grade Beam	Reinforced concrete beam at ground level, typically connecting piers.
Grading Plan	Drawing showing existing and final ground elevations around building.
Green Lumber	Freshly cut lumber with high moisture content. Should be avoided for framing.
Grout	Thin mortar filling joints between tiles; or concrete filling CMU cells.
Gusset	Plywood or metal plate connecting and strengthening truss or frame joints.
Gutter	Horizontal trough at roof edge collecting rainwater.
Gypsum Board	See drywall.

H

H — construction terms
Term	Definition
Hanger	Metal bracket supporting joist, beam, or other member. Examples: joist hanger, beam hanger.
Header	Horizontal structural member spanning opening (door, window) and supporting load above.
Hip	Exterior angle where two roof slopes meet.
Hip Roof	Roof with slopes on all four sides meeting at roof peak.
Hold-Down	Metal bracket anchoring wall to foundation, resisting uplift in high-wind or seismic areas.
House Wrap	Synthetic fabric wrapped around exterior sheathing as air and moisture barrier. Brand example: Tyvek.
HVAC	Heating, Ventilation, and Air Conditioning system.

I

I — construction terms
Term	Definition
I-Joist	Engineered floor joist shaped like steel I-beam, with OSB web and lumber flanges. Stronger and more consistent than dimensional lumber.
Impact Fee	Fee charged by municipality for infrastructure impact of new construction.
Insulated Concrete Form (ICF)	Foam forms remaining in place as insulation after concrete pour. Creates highly-insulated walls.
Isolation Joint	Separation between concrete slabs or between slab and structure allowing independent movement.
IRC (International Residential Code)	Model building code adopted by most US jurisdictions for one- and two-family dwellings.

J

J — construction terms
Term	Definition
J-Channel	Vinyl siding accessory trim shaped like "J" used around windows and at corners.
Jack Rafter	Shortened rafter running from wall plate to hip rafter or from valley rafter to ridge.
Jack Stud	Vertical framing member supporting header at side of door or window opening. Also called trimmer stud.
Jamb	Side and top members forming door or window frame.
Joist	Horizontal framing member supporting floors or ceilings. Typically spaced 12", 16", or 24" on center.
Joist Hanger	Metal bracket supporting end of joist where it meets beam or header.

K

K — construction terms
Term	Definition
Keyway	Groove formed in concrete footing to lock foundation wall in place.
Kiln-Dried	Lumber dried in kiln to reduce moisture content, typically to 19% or less. More stable than air-dried lumber.
King Stud	Full-length vertical framing member beside door or window opening, running from bottom plate to top plate.
Knee Wall	Short wall under sloped ceiling in attic space, typically 3-4 feet tall.
Knockout	Removable disk in electrical panel or junction box for bringing in conduit or cable.

L

L — construction terms
Term	Definition
Lag Bolt	Large wood screw with hex head, also called lag screw. Used for heavy connections.
Laminate	Material made of thin layers bonded together; often refers to plastic laminate countertops or laminate flooring.
Landing	Platform in stairway where direction changes, or at top/bottom of stairs.
Lap Siding	Horizontal siding where upper pieces overlap lower pieces. Also called clapboard.
Lateral Load	Horizontal force from wind or earthquake. Resisted by shear walls and diaphragms.
Lath	Thin strips of wood or metal providing base for plaster application.
Ledger	Horizontal board attached to wall or beam supporting joists.
Let-In Brace	Diagonal brace notched into wall studs to prevent racking.
Lien	Legal claim against property for unpaid materials or labor. See mechanic's lien.
Lien Waiver	Document releasing lien rights upon payment. Critical for owner-builders to collect from all subcontractors and suppliers.
Lineal Foot	One foot of length, regardless of width. Used for pricing molding, base, etc.
Lintel	Horizontal support above opening, similar to header. Often refers to masonry or steel.
Live Load	Variable weight from occupants, furniture, snow, etc. Compare to dead load.
Load-Bearing Wall	See bearing wall.
Lookout	Horizontal framing member supporting roof overhang at gable end.
Lot Line	Legal boundary of property. Setbacks measured from lot lines.
Louver	Slatted opening allowing ventilation while blocking rain and light.
Low-E (Low Emissivity)	Window coating reflecting infrared light, reducing heat transfer.
LVL (Laminated Veneer Lumber)	Engineered lumber made from thin wood veneers glued together. Used for beams, headers, and rim joists.

M

M — construction terms
Term	Definition
Main Panel	Primary electrical distribution panel containing main breaker and branch circuit breakers.
Mansard Roof	Roof with two slopes on all four sides, lower slope nearly vertical. French architectural style.
Mastic	Thick adhesive for setting tile or adhering materials.
MDF (Medium-Density Fiberboard)	Engineered wood product made from wood fibers and resin. Common for painted trim and cabinets.
Mechanic's Lien	Legal claim by contractor or supplier against property for unpaid work. Owner-builders must carefully manage lien waivers to prevent.
Millwork	Finished wood products: doors, windows, trim, stairs, cabinets. Typically manufactured in mill.
Miter	Angled cut, typically 45°, where two pieces join at corner.
Moisture Barrier	Material preventing water vapor transmission. See vapor barrier.
Molding	Decorative trim with shaped profile: crown, base, casing, etc.
Monolithic Slab	Concrete slab and footing poured in single operation.
Mortar	Mixture of cement, lime, sand, and water bonding masonry units.
Mudsill	See sill plate.
Mullion	Vertical member separating and supporting window or door units.
Muntin	Thin bar dividing glass panes within window sash. Modern windows often have false muntins.

N

N — construction terms
Term	Definition
Nailer	Blocking installed to provide nailing surface, like for drywall or cabinets.
Nail Pop	Drywall nail or screw pushing through finished surface, usually from lumber shrinkage.
National Electrical Code (NEC)	Standard for electrical installations, adopted by most jurisdictions.
Newel	Large post at top, bottom, or turn of stairway supporting handrail.
Nominal Dimensions	Named size of lumber before planing. A "2x4" is nominally 2"x4" but actually 1.5"x3.5". See actual dimensions.
Non-Bearing Wall	Partition wall supporting no structural load. Can be removed without structural concerns.
Nosing	Rounded edge of stair tread projecting beyond riser.

O

O — construction terms
Term	Definition
O.C. (On Center)	Measurement from center of one framing member to center of next. Standard spacings: 12", 16", 24".
Oriented Strand Board (OSB)	Engineered wood panels made from compressed wood strands. Common for sheathing and subflooring.
Outrigger	Extension of rafter or joist beyond wall to support overhang.
Owner-Builder	Property owner serving as their own general contractor. You.
Owner-Builder Permit	Special permit for property owners acting as their own contractor. Requirements vary by jurisdiction.

P

P — construction terms
Term	Definition
Panel	Electrical distribution box containing circuit breakers. Also, large sheet material like plywood or drywall.
Parapet	Low wall extending above roof line.
Parging	Thin coat of mortar applied to foundation or chimney for waterproofing or appearance.
Partition	Interior wall dividing space. May be bearing or non-bearing.
Penny (d)	Nail sizing system. 16d (16-penny) nail is 3.5" long. Originated from price per 100 nails.
Perimeter Foundation	Foundation walls around building perimeter supporting exterior walls.
Perm	Measure of water vapor transmission through material. Low-perm = vapor barrier; high-perm = vapor permeable.
PEX (Cross-Linked Polyethylene)	Flexible plastic pipe for water supply. Easier to install than copper, resistant to freezing.
Pier	Isolated concrete column supporting concentrated load. Common for decks and posts.
Pilaster	Thickened vertical section of masonry wall, providing lateral support or carrying concentrated load.
Pitch	Slope of roof expressed as rise over run. 6:12 pitch rises 6" per 12" of horizontal distance.
Plan Check	Building department review of construction plans for code compliance.
Plank	Thick lumber, typically 2" to 4" thick and 6" or wider.
Plate	Horizontal framing member. Bottom plate at floor; top plate at ceiling; sole plate synonymous with bottom plate.
Platform Framing	Modern framing method where each story built as separate platform. Compare to balloon framing.
Plenum	Space used for air circulation, like cavity above suspended ceiling or below raised floor.
Plumb	Exactly vertical. Checked with level or plumb bob.
Plumb Bob	Weight on string establishing vertical line.
Ply	Single layer in plywood or built-up material. 1/2" plywood is typically 5-ply.
Plywood	Engineered wood panels made from thin wood layers (plies) glued with grain alternating directions.
Pointing	Finishing mortar joints in masonry; or repairing deteriorated mortar joints.
Post	Vertical structural member, typically larger than stud. Supports beams.
Post-and-Beam	Framing system using larger, widely-spaced posts and beams rather than stud walls.
Pressure-Treated (PT)	Lumber treated with preservative forced deep into wood under pressure. Required for ground contact or weather exposure.
PSF (Pounds per Square Foot)	Unit for measuring distributed loads, like floor live loads or snow loads.
PSI (Pounds per Square Inch)	Unit for measuring pressure or material strength. Concrete specified by compressive PSI.
Punch List	List of incomplete or defective items to be corrected before final payment.
Purlin	Horizontal roof framing member perpendicular to rafters, providing intermediate support.
PVC (Polyvinyl Chloride)	White plastic pipe used for DWV systems and buried/exterior cold-water lines. Most plumbing codes do NOT permit rigid PVC for interior potable-water distribution; use CPVC for interior hot- and cold-water supply.

Q

Q — construction terms
Term	Definition
Quarry Tile	Unglazed ceramic tile, typically for floors.
Quarter Round	Small molding with quarter-circle profile, used to cover gap between floor and baseboard.
Queen Post	Vertical member in truss, typically in pairs between peak and lower cord.
Quoin	Decorative corner treatment using contrasting material or larger masonry units.

R

R — construction terms
Term	Definition
R-Value	Measure of insulation's resistance to heat flow. Higher R-value = better insulation.
Rabbet	L-shaped groove cut along edge of lumber.
Racking	Lateral distortion of wall or frame under load. Prevented by bracing or sheathing.
Radiant Barrier	Reflective material in attic reducing radiant heat transfer. Common in hot climates.
Rafter	Sloped roof framing member running from ridge to wall plate.
Rafter Tail	Portion of rafter extending beyond exterior wall forming eave overhang.
Rail	Horizontal member in door, window sash, railing, or fence panel.
Rake	Sloped edge of gable roof.
Receptacle	The device you plug cords into. Per NEC Article 100, a receptacle is one type of "outlet" — "outlet" is the broader term that also covers lighting and hardwired connections.
Rebar (Reinforcing Bar)	Steel bar embedded in concrete for tensile strength. Specified by number indicating diameter in eighths of inch (#4 = 4/8" = 1/2" diameter).
Retaining Wall	Wall holding back earth at grade change.
Retainage	Portion of payment withheld until project completion, typically 5-10%.
Return	Finish trim returning around corner to wall, like at end of window sill.
Reveal	Portion of surface left exposed, like narrow edge of door jamb visible beyond casing.
Ridge	Horizontal line at top of roof where slopes meet.
Ridge Board	Horizontal board at roof peak where rafters meet. Not structural in conventional framing.
Ridge Vent	Continuous vent along roof ridge allowing hot air to escape attic.
Rim Joist	Vertical board at perimeter of floor framing, closing off joist bays. Also called band joist.
Rise	Vertical height of stairs, roof, or other sloped element.
Riser	Vertical board between stair treads. Maximum 7-3/4" in residential construction.
Romex	Brand name for non-metallic sheathed cable (NM cable), commonly used for residential wiring.
Roof Truss	Engineered roof framing component, typically pre-fabricated, replacing rafters and ceiling joists.
Rough Opening (RO)	Framed opening for door or window before installation. Typically 1" larger than unit size.
Rough-In	Installation of mechanical/electrical/plumbing systems before walls are closed, while framing is still exposed.
Rough Sawn	Lumber surface as it comes from saw, not planed smooth. Used for rustic appearance.
Run	Horizontal distance of stairs, roof, or drain pipe slope.

S

S — construction terms
Term	Definition
Saddle	See cricket. Also, threshold at exterior door.
Sash	Movable part of window holding glass.
Scab	Short piece of lumber fastened alongside another for reinforcement.
Scarf Joint	Angled joint connecting two pieces end-to-end.
Schedule	List or table on plans showing repeated items like doors, windows, or finishes.
Scratch Coat	First layer of stucco or plaster, scored to provide key for subsequent coats.
Screed	Tool or process for leveling concrete; or strip establishing level for concrete.
Scribing	Marking material to fit irregular surface, like cabinet to uneven wall.
Seismic	Related to earthquakes. Seismic zones have special structural requirements.
Self-Closing	Door or gate required by code to close automatically, like at pool or garage.
Service	Electrical utility connection to building.
Service Panel	See main panel.
Setback	Required distance between building and property line, established by zoning.
Settlement	Downward movement of building or foundation due to soil compression or consolidation.
Shear Wall	Wall designed to resist lateral (horizontal) loads from wind or earthquakes. Requires special sheathing and nailing.
Sheathing	Structural panels covering exterior wall or roof framing: OSB, plywood, foam board.
Shed Roof	Roof with single slope, like half of gable roof.
Shim	Thin wedge of wood or plastic used to level or plumb during installation.
Shoe	See bottom plate.
Siding	Exterior wall covering: wood, vinyl, fiber-cement, metal, etc.
Sill	Horizontal bottom member of door or window opening. Also, see sill plate.
Sill Plate	Horizontal lumber member bolted to top of foundation, supporting wall framing. Also called mudsill.
Sill Sealer	Foam gasket between foundation and sill plate reducing air infiltration.
Single-Ply Roofing	Rubber or synthetic membrane roofing applied in single layer. Common for flat roofs: TPO, EPDM, PVC.
Skylight	Window installed in roof.
Slab	Concrete floor poured directly on grade.
Slab-on-Grade	Foundation type where concrete floor slab poured at ground level serves as foundation and floor.
Sleeper	Wood strip laid on concrete as nailer for finish floor.
Slope	Angle of roof, drain pipe, or grade. Roof slope often expressed as pitch.
Soffit	Underside of eave overhang; or boxed-in area above cabinets.
Soil Stack	Vertical DWV pipe carrying toilet waste.
Sole Plate	See bottom plate.
Span	Horizontal distance between structural supports.
Span Table	Reference showing maximum allowable spans for joists, rafters, beams based on size, species, spacing, and load.
Spalling	Flaking or breaking of concrete or masonry surface, often from freeze-thaw cycles.
Specifications (Specs)	Written detailed description of materials, equipment, and workmanship requirements. Accompanies drawings.
Square	100 square feet of surface area. Roofing and siding often sold by square. Also, right angle (90°).
Stack	Vertical run of soil or waste pipe.
Stair Carriage	See stringer.
Starter Strip	First course of siding or shingles, often special profile.
Stile	Vertical member in door panel or window sash.
Stirrup	U-shaped rebar in concrete beam resisting shear forces. Also, see joist hanger.
Stop	Molding or edge preventing door or window from opening too far.
Stringer	Diagonal board supporting stair treads and risers. Also called stair carriage.
Structural Engineer	Licensed professional designing structural systems and stamping structural drawings.
Stucco	Cement-based exterior plaster finish applied in multiple coats.
Stud	Vertical framing member in wall, typically 2x4 or 2x6 spaced 16" or 24" o.c.
Subcontractor	Specialty contractor hired to complete specific scope: electrician, plumber, HVAC, etc.
Subfloor	Structural floor surface, typically OSB or plywood, installed on floor joists. Finish floor installed over subfloor.
Subpanel	Secondary electrical panel fed from main panel.
Sump	Pit in basement floor collecting water, with pump to remove it.

T

T — construction terms
Term	Definition
Tack Strip	Wood strip with protruding tacks securing carpet around room perimeter.
Tape	Process of finishing drywall joints with paper tape and compound. Also, surveyor's measuring tape.
T&G (Tongue and Groove)	Lumber milled with projection on one edge (tongue) fitting into groove on adjacent board.
Tempered Glass	Heat-treated glass that breaks into small pieces rather than sharp shards. Required by code in hazardous locations.
Termite Shield	Metal barrier on top of foundation preventing termite passage. More common in high-termite areas.
Thermal Break	Insulating material separating conductive materials to reduce heat transfer.
Threshold	Bottom piece of exterior door opening, sloped to shed water.
Tie	Metal device connecting structural elements; or horizontal member in concrete form holding sides together.
Toenail	Driving nail at angle to join perpendicular pieces.
Top Plate	Double horizontal framing member at top of wall supporting ceiling joists or roof framing.
TPO (Thermoplastic Polyolefin)	White rubber membrane for flat or low-slope roofing.
Transom	Window above door.
Tread	Horizontal board on stair you step on. Minimum 10" in residential construction.
Trimmer	See jack stud.
Truss	Engineered structural component using triangular web design. Common for roofs and floors.
Turn of Nut	Method of tightening bolts by specific angular rotation rather than torque measurement.

U

U — construction terms
Term	Definition
U-Factor	Whole-assembly rate of heat transfer through a window (frame, spacer, and glass together), measured under NFRC procedures. Lower U-factor = better insulation. U and R are reciprocal as units (U = 1/R), but a window's rated U-factor is not simply the inverse of an insulation R-value.
UBC (Uniform Building Code)	Older model building code, replaced by International Building Code (IBC).
Underlayment	Layer between structural floor and finish floor, or between roof deck and shingles. Provides smooth surface or waterproofing.
Utility Easement	Legal right for utility company to access portion of property for infrastructure.

V

V — construction terms
Term	Definition
Valley	Interior angle where two roof slopes meet.
Valley Rafter	Diagonal rafter in valley where two roofs meet.
Vapor Barrier	Material preventing water vapor passage. In cold climates, installed on warm side of insulation. Also called vapor retarder.
Variance	Permission from a zoning board of appeals to deviate from a ZONING ordinance (e.g., setback, height, or lot-coverage rules) based on a unique property hardship. It does not apply to building-code requirements.
Veneer	Thin decorative layer over structural substrate. Examples: brick veneer, wood veneer.
Vent	Opening allowing air circulation; or pipe allowing sewer gases to escape above roof.
Vent Stack	Vertical DWV pipe extending through roof, allowing sewer gases to escape and maintaining atmospheric pressure in drains.
Verge Board	See barge board.

W

W — construction terms
Term	Definition
Wainscoting	Decorative wall covering from floor to waist height, typically wood panels or bead board.
Waiver of Lien	See lien waiver.
Wall Tie	Metal connector linking brick veneer to structural wall.
Waste Pipe	Pipe carrying wastewater (not sewage). Compare to soil pipe.
Waterproofing	Treatment preventing water penetration, typically below-grade applications.
Weatherstripping	Material sealing gaps around doors and windows to prevent air infiltration.
Weep Hole	Small opening in masonry allowing water drainage.
Wet Wall	Wall containing plumbing, typically thicker to accommodate pipes.
Wind Bracing	Diagonal or structural sheathing resisting wind loads.
Window Schedule	Table on plans listing all windows with sizes, types, and specifications.
Wire Mesh	Steel mesh reinforcing concrete slabs. Also called welded wire fabric (WWF) or wire mesh.
WRB (Weather Resistant Barrier)	Layer preventing water infiltration while allowing vapor passage. Common example: house wrap.

Z

Z — construction terms
Term	Definition
Zone	Area served by single heating/cooling thermostat. Also, geographic area with specific building code requirements (seismic zone, climate zone, etc.).
Zoning	Local ordinance regulating land use, setbacks, building height, and property development.
Zoning Variance	See variance.

Owner-Builder Specific Terms

Owner-Builder Specific Terms
Term	Definition
Owner-Builder Permit	Special building permit issued when property owner acts as general contractor. Requirements vary: some jurisdictions require affidavit, testing, or insurance; others treat same as contractor permits.
Owner-Builder Exemption	Exemption from contractor licensing requirements when building your own residence. Typically requires owner intent to occupy, not sell immediately.
Construction-to-Permanent Loan	Single loan converting from construction financing to permanent mortgage after completion. Simplifies financing for owner-builders.
Draw Schedule	Timeline for releasing construction loan funds based on completion milestones. Owner-builders must carefully coordinate draws with subcontractor payments.
Builder's Risk Insurance	Property insurance during construction covering structure, materials, and equipment from theft, vandalism, fire, weather, etc. Critical for owner-builders who may not be covered by subcontractor policies.
Interim Occupancy	Temporary certificate allowing limited use before final certificate of occupancy. Rarely granted for residential construction.
Lien Release Requirements	Documentation owner-builders must collect from all subcontractors and suppliers with each payment, preventing future mechanic's lien claims.
Sweat Equity	Value of owner-builder's labor contributing to project. May count toward down payment for some construction loans.
Self-Help Building	Another term for owner-builder construction, more common historically.

Code and Permitting Terms

Code and Permitting Terms
Term	Definition
AHJ (Authority Having Jurisdiction)	Local building department with authority to enforce codes and issue permits. Your AHJ interprets code for your project.
Code Cycle	Period between updates to building codes, typically 3 years. Projects typically built to code in effect when permit applied for.
Adopted Code	Model code officially adopted by jurisdiction. May include local amendments.
Amendment	Local change to model code. Critical to review your jurisdiction's amendments.
Certificate of Occupancy (CO)	Final permit sign-off allowing occupancy. Issued after final inspection passes.
Temporary Certificate of Occupancy (TCO)	Allows occupancy with minor items incomplete. Time-limited and may have conditions.
Red Tag	Notice from inspector stopping work due to code violation or unsafe condition. Work cannot continue until violation corrected and re-inspected.
As-Builts	Final drawings showing construction as actually built, including any deviations from approved plans. Required in some jurisdictions before CO issued.
Substantial Completion	Point where building is usable for intended purpose even if minor items remain. Affects warranties and insurance.
Final Inspection	Last inspection before certificate of occupancy issued. Verify all required inspections passed and punch list complete before scheduling.

Related Resources

Complete Project Checklists - Use this terminology in context
Building Code Guide - Understand code applications
Templates and Forms - See terms used in contracts
Subcontractor Selection - Speak their language
Inspection Guides - Know what inspectors look for

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