Construction glossary
Construction estimating and takeoff terms, explained with the math
Every definition is written by estimators for estimators: what the term means, how it is measured, and a worked example with real numbers. 89 terms and growing.
Process and contract terms
Addendum
An addendum is a formal written revision to the bidding documents that the architect or owner issues during the bid period, before bids are due. It can change drawings, specifications, or the instructions to bidders, and it becomes part of the contract documents that every bidder must price. Addenda are numbered sequentially and distributed to all plan holders so every contractor is bidding the same scope.
AIA G702/G703
AIA G702/G703 is the American Institute of Architects' standard pair of pay application forms: G702 is the Application and Certificate for Payment summary sheet, and G703 is the Continuation Sheet that breaks the contract sum into schedule of values line items. Contractors submit the pair, usually monthly, to bill for work completed and materials stored, and the architect certifies the amount due. Together they are the default progress billing format on US commercial projects.
Buyout
Buyout is the post-award phase of a construction project where the general contractor converts the line items in its winning estimate into committed subcontracts and purchase orders. The team levels subcontractor bids, verifies scope coverage, negotiates final pricing, and awards each work package against the budget set on bid day. The gap between each budgeted amount and the committed amount is tracked as buyout savings or buyout loss.
Change order
A change order is a written amendment to a construction contract that changes the scope of work, the contract price, the schedule, or all three after the contract is signed. Once executed by both parties it becomes part of the contract, and its value is carried on the pay application as an approved change. On commercial projects it is the formal mechanism for pricing and getting paid for work that was not in the original bid.
CSI MasterFormat
CSI MasterFormat is the standard classification system, published by the Construction Specifications Institute, that organizes US and Canadian construction specifications and cost information into 50 numbered divisions. Each division covers a work result, such as Division 03 Concrete or Division 09 Finishes, and breaks into six-digit section numbers like 03 30 00 Cast-in-Place Concrete. Estimators use those same numbers to organize takeoffs, cost codes, and subcontractor bid packages so every line in an estimate ties back to a spec section.
General contractor (GC)
A general contractor (GC) is the company that holds the prime contract with the project owner and takes single-point responsibility for delivering the building: hiring and coordinating subcontractors, managing schedule, site logistics, and safety, and finishing the work for the contract price. Most commercial GCs subcontract the majority of the trades and earn their money through general conditions, overhead, and fee. A construction manager (CM) differs mainly in how and when it is hired; an agency CM advises the owner for a fee and never holds the trade contracts, while a GC always does.
GMP (guaranteed maximum price)
A guaranteed maximum price (GMP) is a contractual cap on what the owner pays the contractor for a defined scope of work, covering the cost of the work plus the contractor's fee. If actual costs finish below the cap, the savings go back to the owner or get divided under a shared savings clause. If costs run over, the contractor absorbs the overrun unless an approved change order raised the cap.
Lien waiver
A lien waiver is a signed document in which a contractor, subcontractor, or supplier gives up the right to file a mechanics lien against the project property in exchange for a payment. There are four standard types: conditional progress, unconditional progress, conditional final, and unconditional final, exchanged at each pay application and at closeout. On US commercial work, waivers travel with the pay app, and money generally does not move until they are in hand.
MEP
MEP stands for mechanical, electrical, and plumbing, the three building systems trades in commercial construction. Mechanical covers HVAC (heating, ventilation, and air conditioning), electrical covers power, lighting, and low voltage systems, and plumbing covers domestic water, sanitary, storm, and gas piping. The work is designed by specialty engineers, installed by licensed subcontractors, and typically represents one of the largest cost blocks in a commercial project budget.
Pay application
A pay application (pay app) is the formal billing package a contractor submits, usually monthly, to request payment for work completed and materials stored during a billing period. On most US commercial projects it uses AIA forms G702, the application and certificate for payment, and G703, the continuation sheet that breaks the contract sum into a schedule of values. Each application shows percent complete by line item, deducts retainage and previous payments, and arrives at the net amount currently due.
Purchase order (PO)
A purchase order (PO) in construction is a written agreement a contractor issues to a supplier to buy specific materials or equipment at stated quantities, unit prices, and delivery terms. Once the supplier accepts it, the PO becomes a binding commitment that locks the quoted price. During buyout, the project team converts winning supplier quotes from the estimate into POs coded to the job's cost codes.
Retainage
Retainage is a percentage of each construction progress payment, typically 5% to 10% in US commercial work, that the owner or general contractor withholds until the work is complete. It protects the paying party against defective or unfinished work and gives the contractor a financial incentive to close out the job. The held funds are released at substantial completion or final closeout, according to the contract's payment terms.
RFI (request for information)
An RFI (request for information) is a formal written question a contractor submits to the architect or engineer of record to resolve a gap, conflict, or ambiguity in the construction documents. Each RFI is numbered, logged, and answered in writing, and the response becomes part of the contract record. RFIs show up both during bidding (as pre-bid questions answered by addendum) and during construction, where the answer can drive cost and schedule changes.
RFP (request for proposal)
An RFP (request for proposal) in construction is a solicitation document the owner issues asking contractors to submit both a price and a proposed approach (team, schedule, methodology), with award based on weighted evaluation criteria rather than price alone. It differs from an ITB (invitation to bid), which uses complete drawings and awards to the lowest responsive bidder, and from an RFQ, which requests either qualifications or a simple price quote. RFPs are standard on design-build, CM at risk, and negotiated commercial work in the US.
RFQ (request for quotation)
In construction, an RFQ (request for quotation) is a procurement document a contractor sends to suppliers or subcontractors asking for firm pricing on a clearly defined scope or a quantified list of materials. Because quantities and specs are already set, price, lead time, and terms are the main points of comparison. It differs from an RFP, which invites proposals weighing approach and qualifications, and an ITB, which invites lump-sum bids on complete contract documents.
Schedule of values (SOV)
A schedule of values (SOV) is a line-item breakdown of the total contract sum that assigns a dollar value to each portion of the work, and it becomes the basis for monthly progress payments. On most US commercial projects the SOV is submitted on the AIA G703 continuation sheet, which backs up the G702 application for payment. Each billing cycle the contractor reports percent complete against every line, and those amounts determine what gets paid.
Subcontractor
A subcontractor is a specialty trade contractor hired by the general contractor, not the owner, to perform a defined scope of work on a project, such as electrical, plumbing, or drywall. The general contractor holds the prime contract with the owner and buys out the job as scope packages, each one covered by a subcontract agreement. On a typical US commercial project, subcontractors perform most of the field work while the GC coordinates schedule, contracts, and payment.
Submittal
A submittal is documentation a contractor sends to the design team for review before ordering, fabricating, or installing a product, most commonly shop drawings, product data sheets, and samples. The architect or engineer checks the submittal against the contract documents and returns it with an action such as approved, approved as noted, or revise and resubmit. Nothing covered by a submittal requirement should be fabricated or installed until that review cycle is complete.
Concrete and masonry
Caisson
A caisson is a deep foundation element: a large diameter shaft drilled into the ground and filled with reinforced concrete so that building loads bypass weak soils and bear on rock or another competent stratum. On US commercial projects the term is used interchangeably with drilled shaft and drilled pier. It differs from a pile, which is typically a slender driven element installed in groups, while a caisson is a single large drilled shaft, often one per column.
CMU (concrete masonry unit)
A CMU (concrete masonry unit) is a precast concrete block, hollow or solid, that masons lay in mortar to build structural and non-structural walls. The standard US unit is nominally 8 in wide x 8 in high x 16 in long, and it takes 1.125 blocks to cover 1 sf of wall, which is how estimators convert wall area into block counts.
Concrete admixture
A concrete admixture is a chemical added to the mix, beyond cement, water, and aggregate, to change how the concrete behaves: air entrainment for freeze thaw durability, accelerators for faster set in cold weather, retarders for hot weather, and plasticizers for flow without extra water. Admixtures are priced per cubic yard on top of the base mix, so the estimator needs to know which ones the spec and the season demand.
Concrete cover
Concrete cover is the clear distance between the surface of embedded reinforcing steel and the nearest outside face of the concrete. It protects rebar from corrosion and fire, and ACI 318 sets it by exposure: 3 in for concrete cast against earth, 2 in for formed concrete exposed to weather or earth, and as little as 3/4 in for interior slabs. For estimators, cover sets bar lengths, chair heights, and accessory counts in every rebar takeoff.
Concrete curing
Concrete curing is the controlled process of keeping fresh concrete moist and at a workable temperature so the cement can hydrate and reach its specified strength. Concrete does not dry to get strong, it cures: the reaction needs water, and losing that water too early permanently caps the strength. Estimators carry curing as a real line item, typically cure compound, wet cure with burlap, or cold weather protection.
Control joint
A control joint is a planned weakened line, sawcut or tooled into concrete or formed into masonry, that controls where shrinkage cracking occurs by forcing the crack to follow a straight, predetermined path. In slabs on grade it is typically cut to about one quarter of the slab depth and spaced at roughly 24 to 36 times the slab thickness in inches. Unlike an expansion joint, it does not fully separate the two sides; the concrete remains continuous below the cut.
Footing
A footing is the widened concrete base at the bottom of a foundation that spreads the building's loads out to the soil. The two main types on commercial work are continuous footings, which run in a strip under walls, and spread footings, which are individual pads under columns. The structural engineer sizes footings from the soil bearing capacity in the geotechnical report, and they are typically the first structural concrete placed on the job.
Formwork
Formwork is the temporary mold, usually job-built plywood and lumber or manufactured panel systems, that holds wet concrete to the shape shown on the drawings until it cures enough to support itself. Estimators measure it in sfca (square feet of contact area), counting every form face that touches concrete, so a wall formed on both sides carries twice the contact area of a single face. On cast-in-place work, forming is often the largest single cost in the concrete package, ahead of the concrete itself.
Grout
Grout in construction is a flowable mix of cement, aggregate, and water poured into the cells of concrete masonry units (CMU) to encase vertical rebar and bond the steel, block, and bond beams into one structural wall. It is a different material from mortar, which is the stiffer mix that beds the units. Estimators quantify masonry grout in cubic yards, driven by block size and the spacing of grouted cells.
Lintel
A lintel is a horizontal structural member that spans an opening in a wall, such as a door or window, and carries the weight of the wall and any loads above the opening to bearing points on each side. In US commercial construction the common types are loose steel angles, precast concrete lintels, reinforced CMU lintels (lintel block or bond beam), and cast-in-place concrete. Estimators count lintels per opening, with length equal to the clear opening width plus bearing at each end.
Parapet
A parapet is the portion of an exterior wall that continues above the roof line, typically 18 in to 42 in tall on flat-roofed commercial buildings. It slows fire spread, gives workers an edge barrier, screens rooftop equipment, and provides a vertical surface where the roof membrane terminates. The top of the wall is capped with coping, and the roof membrane turns up the parapet face as base flashing.
Pier
A pier in construction is a vertical structural member, usually concrete or masonry, that carries building loads down to soil or rock strong enough to support them. In US commercial work the term most often means a drilled pier (also called a drilled shaft or caisson), a cylindrical hole drilled into the ground and filled with reinforced concrete. Piers are used where shallow spread footings cannot reach adequate bearing.
Rebar
Rebar (reinforcing bar) is deformed steel bar embedded in concrete to carry the tensile forces that concrete cannot resist on its own. US bar sizes run #3 through #18, and the size number is the bar diameter in eighths of an inch, so a #4 bar is 1/2 inch in diameter and a #5 bar is 5/8 inch. Estimators take rebar off in linear feet, convert to pounds with standard unit weights (a #5 bar weighs 1.043 lb per ft), and price it by the ton.
Slab on grade
A slab on grade (SOG) is a concrete slab placed directly on prepared ground, with the soil providing continuous support, so it serves as the building's ground floor rather than spanning between supports. A typical commercial assembly, from the bottom up, is compacted subgrade, a granular base course, a vapor barrier, reinforcement (welded wire mesh, rebar, or fibers), and the concrete slab itself, commonly 4 in to 6 in thick with a troweled finish and a curing application.
Stucco
Stucco is a portland cement plaster applied in coats over masonry, concrete, or lath on framed walls to form a hard, weather-resistant exterior wall finish. In US commercial work the standard system is three-coat stucco: a scratch coat, a brown coat, and a finish coat, about 7/8 in total thickness over metal lath. Estimators take it off in square feet (sf) of net wall area with openings deducted, then price the lath, accessories, and plaster as one system.
Estimating concepts
Allowance
An allowance in construction is a fixed dollar amount written into the contract to cover a specific scope item that cannot be accurately priced at bid time, usually because the owner has not made a final selection (flooring, hardware, light fixtures). The contractor carries that amount in the contract sum, and once the actual cost is known, the contract is adjusted up or down by change order to match what was really spent.
Assembly estimating
Assembly estimating is a method where the components of a building system are priced together as one unit instead of as separate line items. A partition assembly priced per linear foot, for example, already includes the metal studs, drywall on both sides, insulation, tape, and paint. It contrasts with unit cost estimating, where each of those items is taken off and priced individually.
Bid leveling
Bid leveling is the process of adjusting subcontractor bids to a common scope so they can be compared accurately. Because subs rarely bid identical inclusions and exclusions, the estimator adds or deducts dollar values for missing or extra scope items, producing a leveled total for each bidder. The leveled totals, not the raw numbers, tell you who is actually low.
Contingency
Contingency is money added to a construction estimate or budget to cover costs that are likely to occur but cannot be specifically identified at the time of pricing. It is typically carried as a percentage of the cost of work, with design contingency covering scope the drawings do not show yet and construction contingency covering execution risk during the build. As the design matures and risk retires, the percentage carried goes down.
General conditions
General conditions are the project-specific costs a contractor incurs to run a job, such as the superintendent, jobsite trailer, temporary utilities, safety, and cleanup, that support the work but never become part of the finished building. They are priced as their own section of the estimate, mostly as time-based costs tied to the project schedule, and billed as line items on the schedule of values.
Hard costs
Hard costs are the direct costs of physically constructing a building: materials, trade labor, equipment, and subcontracted work that becomes part of the finished structure. They are distinct from soft costs, which cover design fees, permits, financing, insurance, and other expenses that do not put work in place. On a typical US commercial project, hard costs represent the largest share of the total project budget.
Markup
Markup in construction is the percentage a contractor adds to direct job costs to cover overhead and profit when setting the bid price. It is calculated on cost rather than on the final price, which is what separates it from margin. A 15% markup on $850,000 of direct cost produces a $977,500 bid but only about a 13% margin.
Material takeoff
A material takeoff (MTO) is the process of measuring construction drawings and listing every material a project needs, with a quantity and unit for each item, so the estimate and the buyout rest on counted quantities instead of guesses. Estimators perform the takeoff before pricing, then extend each quantity against unit costs to build the bid. The term is often used interchangeably with quantity takeoff (QTO), though a material takeoff strictly refers to the buy list of materials itself.
Overhead and profit
Overhead and profit (O&P) is the markup a contractor adds to the direct cost of construction work to cover business operating expenses and earn a return for taking on the project's risk. Overhead recovers indirect costs such as office staff, rent, insurance, and estimating, while profit is what remains after all costs are paid. A common illustrative structure in US commercial work is 10 percent overhead plus 10 percent profit added to direct cost.
Quantity takeoff
A quantity takeoff is the process of measuring and counting every material and work item from a set of construction drawings, then listing the results in standard units such as cubic yards, square feet, linear feet, and each. It is the first step of every cost estimate, because each priced line item starts with a measured quantity. Estimators perform the takeoff from the plans and specifications before applying any unit prices.
ROM estimate
A ROM estimate (rough order of magnitude estimate) is an early conceptual cost estimate prepared before design exists, used to test whether a project is financially feasible. It is built from historical unit rates such as dollars per square foot rather than a quantity takeoff. Commonly cited accuracy ranges run from about minus 25 percent to plus 75 percent, and AACE International class 5 guidance allows even wider spreads.
Soft costs
Soft costs in construction are the expenses required to deliver a project that do not pay for the physical building itself, such as design fees, permits, insurance, legal fees, financing costs, and testing. They sit apart from hard costs (labor, materials, equipment, and subcontracts) and on typical US commercial projects are often budgeted in the range of 15 to 30 percent of hard costs. Owners and developers carry most soft costs, but estimators need to know which ones land in the contractor's bid.
Takeoff
A takeoff in construction is the process of measuring and counting every item of work from the project drawings, producing quantities such as 14 doors, 240 lf of partition, or 1,800 sf of slab. It is the first step in building an estimate: the takeoff establishes how much work there is, and the estimator then applies unit costs to those quantities to price the job. It is also called a quantity takeoff (QTO) or material takeoff (MTO).
Unit cost
Unit cost in construction is the cost to furnish and install one measured unit of a work item, expressed in dollars per unit such as $/cy for concrete, $/sf for drywall, or $/lf for pipe. Estimators multiply a unit cost by the takeoff quantity to price each line item, then sum those extensions to build the estimate. A complete unit cost typically rolls up labor, material, and equipment for that scope, and sometimes markup depending on how the price book is set up.
Steel and structural
Anchor bolt
An anchor bolt is a threaded steel rod, typically ASTM F1554 grade 36, 55, or 105, cast into a concrete footing or pier to anchor a steel column baseplate to the foundation. The bolts are placed by the concrete trade before the pour, then the steel erector sets the column over the projecting threads and bolts it down. Estimators count them each from the anchor bolt plan and baseplate details, usually four per column.
Baseplate
A baseplate is a steel plate shop welded to the bottom of a structural column that spreads the column load onto the concrete foundation below. The plate bears on a bed of non-shrink grout over the footing or pier and is held down by cast-in anchor bolts. Estimators pull baseplate sizes from the column schedule or base details and carry the plate weight inside the steel tonnage.
Bolt grades
Bolt grades are the strength classifications for high strength structural bolts, historically ASTM A325 (120 ksi minimum tensile) and A490 (150 ksi), both now consolidated as grades within ASTM F3125. The grade governs how much load each bolt can carry, so the connection details on the structural drawings call out grade, diameter, and length for every joint. Estimators count and price bolts by grade because A490 and tension control assemblies cost meaningfully more than plain A325 hardware.
Camber
Camber is an upward curvature fabricated into a steel beam so that it deflects down to flat once the dead load of the deck and wet concrete is applied. Framing plans call it out per beam, typically as a note like C = 3/4 in on longer composite floor beams. For estimators it is not a quantity to measure but a per-beam fabrication cost adder, and getting it wrong shows up later as extra concrete in the slab.
Field weld
A field weld is a weld made at the job site during steel erection rather than in the fabrication shop, identified on drawings by a flag at the bend of the weld symbol. Because field welding involves position welding, limited access, weather, staging, and field inspection, the same weld costs several times more than its shop equivalent. Estimators count field welds from the erection drawings and price them as erection labor.
Fireproofing (SFRM)
Fireproofing (SFRM) is spray applied fire resistive material, a cementitious coating sprayed onto structural steel beams, girders, and columns so the assembly achieves a code required fire resistance rating, such as 1, 2, or 3 hours, under a listed UL design. The required thickness depends on the rating hours and the member's W/D ratio, roughly 1-1/2 inch for a 2 hour rating on a typical beam. Estimators take it off in square feet of steel surface area and price it per sf.
Galvanizing
Galvanizing in construction is the hot-dip application of a zinc coating to fabricated steel per ASTM A123 to protect it from corrosion. It is specified for exterior and moisture-exposed steel such as lintels, stairs, railings, and embed plates, and it is priced per pound or per hundredweight (cwt) of steel on top of the fabrication cost. Estimators take off the weight of every member flagged galvanized in the finish schedule and general notes.
Girder
A girder is the primary horizontal member in a steel frame that carries other beams: infill beams frame into the girder, and the girder frames into the columns. Estimators take girders off by member from the framing plans, multiplying the weight per foot in the shape callout (a W24x76 weighs 76 lb per foot) by the member length, then converting total pounds to tons for pricing.
Girt
A girt is a horizontal wall framing member, usually a cold formed Z or C section in a pre-engineered metal building, that spans between columns and supports the exterior wall panels. It is the wall counterpart of the roof purlin and is sized and spaced by the building manufacturer. Estimators take girts off in linear feet per wall: wall height divided by girt spacing gives the number of rows, and rows times wall length gives the footage.
Gusset plate
A gusset plate is a flat steel plate that connects a brace to a beam, column, or truss chord, transferring the brace force into the main frame. It appears at every brace work point in braced frames and at truss panel points. Estimators count gusset plates each from the connection details and roll their weight into the connection or fabrication allowance on the steel tonnage.
HSS (hollow structural section)
HSS (hollow structural section) is square, rectangular, or round steel tubing, produced to ASTM A500, used in commercial buildings for columns, braces, canopy framing, and handrail posts. A designation like HSS6x6x3/8 gives the outside dimensions and wall thickness, and that size runs about 27.5 lb per ft. Estimators take HSS off the same way as other steel members: linear feet by size, converted to pounds using the weight per foot.
KSI (kips per square inch)
KSI (kips per square inch) is the unit US structural engineers use to state the strength of steel, and since a kip is 1,000 pounds, 1 ksi equals 1,000 psi. Common values on commercial drawings are 36 ksi yield for A36 plate and angle, 50 ksi yield for A992 wide flange shapes, and 120 ksi tensile for A325 bolts. For estimators, the ksi grade sets the material price per pound while the takeoff quantity stays the same.
Metal decking
Metal decking is corrugated steel sheet installed over steel framing to form the structural surface of a roof or floor. Commercial jobs use two main types: Type B 1.5 inch roof deck in 20 to 22 gauge, and 2 or 3 inch composite floor deck that acts together with its concrete fill. Estimators take it off in square feet from the framing plans and add 5 to 10 percent for laps and waste.
Metal stud (structural)
A structural metal stud is a cold formed steel (CFS) load bearing stud used to frame exterior walls, load bearing walls, and full mid-rise CFS structures in commercial construction. Unlike non-structural drywall studs, structural studs are rolled from heavier gauge steel, commonly 54 mil (16 gauge) or thicker, and carry designations like 600S162-54 that spell out web depth, flange width, and thickness. They are specified under CSI Division 5 cold formed metal framing, not Division 9 finishes.
Moment connection
A moment connection is a rigid structural steel connection that transfers bending moment from a beam into a column, not just vertical shear like a standard connection. It is typically built with complete joint penetration (CJP) flange welds plus a bolted web, or with bolted end plates, and it costs far more than a simple shear connection. On framing plans each one is identified by a symbol or tag at the beam end, and estimators count them each and carry a cost adder per connection.
Plate steel
Plate steel is flat rolled steel specified by its thickness, used in commercial construction for column baseplates, gusset plates, stiffeners, cap plates, and embed plates. Because steel weighs 490 pounds per cubic foot, a plate 1 inch thick weighs 40.8 pounds per square foot, the constant estimators use to turn plate dimensions into weight. Plate is taken off as area x thickness x 40.8 and priced with the rest of the structural steel in pounds or tons.
Purlin
A purlin is a secondary roof framing member that spans between the primary structural frames and supports the roof deck or roof panels. In pre-engineered metal buildings, purlins are typically cold formed Z sections, such as an 8 inch Z purlin, spaced about 5 ft on center. Estimators take them off in linear feet from the roof framing plan and price them per lf or by weight.
Shear stud
A shear stud is a headed steel anchor, most commonly 3/4 inch in diameter, welded through the metal deck to the top flange of a steel beam so the concrete slab and the beam act together as one composite member. The studs transfer horizontal shear between the slab and the steel, which lets the design use a lighter beam than the steel could carry alone. On framing plans they appear as a count in parentheses next to each composite beam, such as (24) studs.
Shop drawings
Shop drawings in construction are the fabricator-produced detail drawings that translate the engineer's design drawings into instructions a shop can build from: every member, plate, hole, weld, and bolt drawn piece by piece. They are reviewed and approved through the submittal process before fabrication starts, and the matching erection drawings tell the field crew where every piece mark lands in the frame. For estimators, the detailing cost and the approval cycle are the two numbers that matter, because together they set the price and the lead time of the steel package.
Steel angle
A steel angle is an L shaped structural steel section, named by its two leg dimensions and thickness, such as L4x4x1/4 at 6.6 lb per ft. On commercial projects, angles serve as loose lintels over masonry openings, edge and shelf angles, bracing members, and frames around floor and roof openings. Estimators take them off in linear feet by size and convert to weight for fabricator pricing.
Steel channel
Steel channel is a hot rolled structural shape with a C shaped cross section, made up of a flat web and two parallel flanges that point the same direction. It comes in two series, standard C shapes and MC miscellaneous channels, and the designation reads depth then weight, so a C8x11.5 is 8 inches deep and weighs 11.5 pounds per foot. On commercial jobs it shows up as stair stringers, frames around roof openings, kickers, and other miscellaneous metals, and estimators take it off in linear feet converted to pounds.
Steel tonnage
Steel tonnage is the total weight of structural steel on a project, expressed in short tons of 2,000 pounds, calculated by summing each member's length times its weight per foot and adding an allowance for connections and details, commonly around 10 percent. It is the controlling quantity for pricing structural steel, because fabrication and erection are both quoted and billed per ton. Estimators compute it from the framing plans, column schedule, and the member designations on the structural drawings.
Stiffener
A stiffener is a steel plate welded to a beam or girder web, or between the flanges, to keep the web from buckling or crippling under load. Bearing stiffeners go at reaction points and under concentrated loads, intermediate stiffeners stabilize deep plate girder webs, and continuity plates do the same job inside moment connections. Estimators count them each from the framing details and price them through plate weight plus fabrication labor.
Weld types
Weld types are the categories of welded connections called out on structural steel drawings, mainly fillet welds, which are triangular welds sized by leg dimension such as 1/4 in or 5/16 in, and groove welds, which come as complete joint penetration (CJP) or partial joint penetration (PJP). The weld symbol on each connection detail tells the fabricator or erector exactly which type and size to make. Estimators care because weld type and size drive fabrication and field labor cost.
Wide flange beam
A wide flange beam is a hot rolled structural steel member with an H shaped cross section, designated by a W followed by its nominal depth in inches and its weight in pounds per linear foot, so a W12x26 is nominally 12 inches deep and weighs 26 lb per foot. It is the most common beam and column shape in US commercial steel framing. Estimators take it off from the framing plans by counting members and converting lengths to pounds and tons.
Units of measure
BF (board foot)
A board foot (bf) is the lumber volume unit equal to a piece 1 inch thick, 12 inches wide, and 1 foot long, which is 144 cubic inches. The formula is nominal thickness in inches times nominal width in inches times length in feet, divided by 12. Framing packages and timbers are often priced per thousand board feet, written MBF.
CY (cubic yard)
A cubic yard (cy) is the standard volume unit in US construction, equal to 27 cubic feet, the volume of a cube measuring 3 feet on each side. Concrete, excavation, gravel, and fill are all ordered and priced by the cubic yard, so estimators convert measured volumes from cubic feet to cy by dividing by 27.
EA (each)
EA (each) is the unit of measure used in construction takeoffs and estimates for items counted as individual pieces rather than measured by length, area, or volume. Doors, plumbing fixtures, light fixtures, and equipment are typical EA items. The estimator counts them on the drawings, enters the quantity as EA, and extends it by a unit cost per item.
Gauge
In construction, gauge is a number that indicates the thickness of sheet metal, including metal studs, roof deck, and flashing, and the scale runs backward: the higher the gauge number, the thinner the metal. A 25 gauge stud has a minimum base metal thickness of about 0.0179 in, while a 20 gauge structural stud is about 0.0329 in, nearly twice as thick. Estimators read gauge callouts on wall types, framing schedules, and specs because lower gauge (thicker) material costs more and is required where walls carry load or exceed limiting heights.
Kip
A kip is a unit of force used in US structural engineering equal to 1,000 pounds, short for kilopound. Column loads, beam reactions, and connection capacities on structural drawings are stated in kips, so a column carrying 150 kips is carrying 150,000 pounds, which is 75 short tons.
LF (linear foot)
A linear foot (LF) is a length measurement equal to 12 inches, measured in a straight line along the run of the work with no regard for width or height. In construction estimating, LF is the standard unit for anything that runs in lengths, such as baseboard, pipe, conduit, curb and gutter, strip footings, and fencing. Estimators measure the run, deduct openings where the material stops, and add waste before pricing per LF.
LS (lump sum)
LS (lump sum) is a unit of measure on construction bid forms and estimates that prices an entire scope of work as one fixed amount with a quantity of 1, rather than a rate multiplied by a measured quantity. The single price covers everything needed to complete that scope and does not change if the work consumes more labor or material than planned. It is the opposite of a unit price item, where payment equals the bid rate times the quantity actually installed and measured.
MBF (thousand board feet)
MBF stands for thousand board feet, the standard unit for pricing and buying framing lumber at the mill and wholesale level in US construction (M is the Roman numeral for 1,000). One board foot is the volume of a board measuring 12 inches by 12 inches by 1 inch in nominal dimensions, so 1 MBF equals 1,000 board feet. Mills, wholesalers, and commodity price indexes quote lumber in dollars per MBF, and estimators convert their framing takeoff to MBF to apply those prices.
PSF (pounds per square foot)
PSF (pounds per square foot) is the unit US construction uses for loads spread over an area: a floor designed for a 100 psf live load must safely support 100 lb of people and movable contents on each square foot, on top of the structure's own weight. Psf values appear in the structural general notes (dead, live, roof, snow, and wind loads) and in the geotech report as allowable soil bearing pressure. To get total load, multiply psf by area in sf: the result is in lb, and dividing by 1,000 converts lb to kips.
PSI (pounds per square inch)
PSI (pounds per square inch) is the unit US construction uses to measure pressure and stress, and on commercial projects it most often describes the compressive strength of concrete. A 4,000 psi mix must withstand 4,000 pounds of force on each square inch, verified by breaking field-cast cylinders at 28 days. Estimators use the psi values on the structural drawings to separate concrete quantities by mix strength and price each class at its own unit cost.
Roof pitch
Roof pitch is the slope of a roof, expressed as inches of vertical rise per 12 inches of horizontal run, such as 6:12. Estimators care about pitch because it converts flat plan area into actual sloped roof area through a slope factor, and roofing material and labor follow the sloped surface, not the footprint. At a 6:12 pitch the slope factor is 1.118, so 1,000 sf of plan area is about 1,118 sf of roof surface.
SQ (square)
A square (SQ) in construction is a unit of area equal to 100 square feet, used mainly in roofing and siding to quantify and price material. A 2,400 square foot roof is 24 squares. Roofers, suppliers, and estimators all bid, order, and bill steep-slope roofing by the square.
SY (square yard)
SY (square yard) is a unit of area equal to 9 square feet, used in US construction to quantify and price broadloom carpet, asphalt paving, concrete flatwork, and similar plan-area work. Estimators take off the area in square feet from the drawings, then divide by 9 to convert to SY, because flooring subs and paving contractors commonly quote and bill these items per square yard.
Wood framing
Bottom plate (sole plate)
A bottom plate, also called a sole plate, is the horizontal framing member at the base of a stud wall that the studs sit on and that anchors the wall to the floor or slab. Where the wall sits on a concrete slab on grade, the bottom plate must be pressure treated (PT) because it contacts concrete and is exposed to moisture.
Header
A header is the horizontal beam over a door, window, or other wall opening that carries the loads from above and transfers them around the opening to the studs on each side. In light-frame walls a header is commonly built up from two or more 2x members, sized by the opening width and the load it carries.
Stud
A stud is a vertical framing member in a wall that carries load from the plates above down to the floor or foundation. In US light-frame work studs are most often 2x4 or 2x6, set at 16 in or 24 in on center, and cut or bought as precuts to suit the wall height.
Top plate
A top plate is the horizontal framing member running along the top of a stud wall that ties the studs together and carries the load from above. In bearing walls it is almost always doubled, so the takeoff is two runs of plate stock along the full wall length plus lap allowance.
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