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. 189 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.

Envelope and finishes

Acoustical ceiling (ACT)

An acoustical ceiling (ACT) is a suspended ceiling made of mineral-fiber or fiberglass tiles laid into a metal grid hung from the structure above, used for sound absorption and access to the plenum. The estimator takes it off by the square foot of ceiling area for tile and by the linear foot of grid and the count of hanger wires for the suspension system. ACT is one of the most common interior finishes in commercial offices, schools, and healthcare.

Base trim (wall base)

Base trim, also called wall base, is the finish material that runs along the bottom of a wall where it meets the floor, covering the joint and protecting the wall from scuffs, mops, and equipment. In commercial interiors it is usually rubber or vinyl cove base in 4 in or 6 in heights, though wood and tile base also appear. The estimator measures it in linear feet of wall perimeter, less door openings, taken off the floor plan and finish schedule.

Batt insulation

Batt insulation is pre-cut fiberglass or mineral wool friction-fit into framing cavities, sized by width to the stud spacing and by R-value to the cavity depth. It is measured in square feet of cavity area at a given R-value, which converts to bags or bundles by coverage. The estimator scopes it from the wall types and the room or partition schedule, matching R-value to the spec.

Casework

Casework in construction is factory-built or shop-built cabinetry: base cabinets, upper (wall) cabinets, countertops, tall units, and similar boxes installed in offices, labs, classrooms, healthcare, and break rooms. It is largely modular and built to standard cabinet dimensions, which separates it from custom millwork. The estimator takes it off the interior elevations and the casework drawings, measuring base and upper runs in linear feet and counting discrete units such as tall cabinets and sinks.

Curtain wall

A curtain wall is a non-load-bearing exterior wall system, usually aluminum framing with glass and metal infill panels, that hangs off the building structure and carries only its own weight and wind load. It is taken off in square feet of system area by elevation, then broken down by panel type, vision glass, and spandrel. Because it is an engineered system, the estimator prices it by the panel and by the square foot, not as loose glass and metal.

Door hardware sets

A door hardware set, or hardware group, is the complete bundle of finish hardware for a single door opening: hinges, lockset or latchset, closer, exit device, stops, seals, and any specialty items, listed together under a set number in the hardware schedule. Each door in the door schedule is assigned a hardware set number, so the estimator prices hardware by counting how many openings carry each set. The takeoff is a count of openings grouped by hardware set, read straight off the door schedule.

Drywall types

In US commercial construction, drywall types are the different gypsum board products specified by core, thickness, and facing for a given assembly: standard 1/2 inch, fire-rated 5/8 inch Type X, moisture-resistant (MR) board, mold-resistant board, abuse-resistant board, and shaftliner. The estimator reads the wall types schedule and fire ratings to pick the right product for each partition. The board type drives both the unit cost and the labor for fastening and finishing.

Eave

The eave is the lower edge of a sloped roof, the line where the roof overhangs or meets the exterior wall along the bottom of the slope. In estimating it is a linear-foot run that organizes the trim, gutter, drip edge, and soffit and fascia scope. You take it off as the perimeter length of the eave condition, not as an area.

EIFS (exterior insulation finish system)

EIFS (exterior insulation finish system) is a multi-layer exterior wall cladding that bonds rigid insulation board to the substrate, then covers it with a reinforced base coat and a textured acrylic finish coat. It is a single proprietary assembly, so the estimator takes it off as square feet of wall area and prices the layers together, not as separate trades. Trim, terminations, and aesthetic reveals are added as linear feet on top of the field area.

EPDM roofing

EPDM roofing is a single-ply synthetic rubber membrane for low-slope commercial roofs, supplied in large sheets and seamed with seam tape rather than heat welds. It is measured in square feet of membrane plus lineal feet of seam tape. The estimator separates field area from perimeter and penetration flashing.

Epoxy flooring

Epoxy flooring in construction is a resinous floor finish, applied in coats over a prepared concrete slab, that cures into a hard, chemical-resistant, seamless surface common in warehouses, kitchens, labs, and back-of-house areas. The estimator prices it by square foot of floor, by coat (primer, body coat, topcoat), with surface prep and any cove base broken out separately. Coverage runs per gallon at a stated mil thickness, so the gallon count comes off the area and the spec's film build.

Facade

A facade is the exterior face of a building, the assembly of cladding, glazing, and trim that encloses each wall elevation. In commercial estimating it is a scope envelope that bundles distinct wall systems (masonry, panel, storefront, curtain wall) priced by their own units. You take it off elevation by elevation, then split it by system.

Fascia

Fascia is the vertical (or near-vertical) trim board that caps the outer edge of a roof at the eave and rake, closing off the ends of the rafters or trusses. In estimating it is a linear-foot run measured around the roof edge, including the added length at each outside corner. It pairs with the soffit to finish the overhang.

Flashing

Flashing is the sheet metal or membrane material installed at joints, transitions, and penetrations in a building envelope to direct water away from the assembly and shed it to the exterior. On a commercial job it shows up as base flashing, counter flashing, step flashing, through-wall flashing, and cap flashing, each detailed at a specific intersection. The estimator takes it off in linear feet by type, since the stock, gauge, and labor differ for each.

Glazing

Glazing is the glass infill in windows, storefront, and curtain wall, most often supplied as insulated glass units (IGUs) of two or three lites separated by a sealed air or argon space. In commercial work it is measured in square feet by opening off the window schedule. The estimator separates glazing from the framing that holds it.

House wrap (WRB)

House wrap, more precisely a weather resistive barrier or WRB, is the sheet membrane applied over exterior sheathing to shed bulk water and air while still letting the wall dry outward. In commercial work it is measured in square feet of wall area plus the seam and flashing tape it takes to make the laps and openings continuous. The estimator scopes it from the exterior elevations and wall sections, not from the floor plan alone.

Level 5 finish

A Level 5 finish is the highest of the six drywall finish levels (0 through 5) defined by the gypsum industry, where a full skim coat of joint compound is applied over the entire surface on top of taped and finished joints. It is specified where critical lighting or high-gloss and dark paint would reveal joint photographing. The estimator distinguishes Level 5 from the more common Level 4 because the skim coat adds material and labor across the whole wall, not just at the seams.

LVT (luxury vinyl tile)

LVT (luxury vinyl tile) is a multilayer resilient flooring with a printed design film and a clear wear layer, supplied as planks or tiles that are glued down, loose-laid, or rigid-core click-installed. The estimator takes it off by the square foot of floor area, then converts to boxes after adding cut waste for the plank layout. LVT is specified across offices, healthcare, hospitality, and retail because it mimics wood or stone, resists water, and needs no wax.

Membrane roofing

Membrane roofing is a single-ply or built-up waterproofing sheet installed over low-slope commercial roofs, measured in square feet and in roofing squares (one square equals 100 sf). The category covers TPO, EPDM, PVC, and modified bitumen membranes. Estimators add laps and waste to the net roof area to get the material quantity.

Millwork

Millwork in construction is custom architectural woodwork: reception desks, wall paneling, ornamental trim, stair rails, and one-off built-ins fabricated to the project's specific drawings rather than from standard catalog sizes. It is shop-built, made to order, and usually specified to an AWI grade for material and joinery quality. The estimator takes it off the millwork drawings and details, measuring custom runs in linear feet and counting discrete fabricated assemblies as units.

R-value

R-value is the measure of an insulation material's resistance to heat flow, expressed per inch of thickness or for a whole assembly, where a higher number means more resistance. In construction it is how the spec defines required thermal performance and how the estimator matches products to the assembly. The key distinction is nominal R-value of the insulation versus the whole-assembly effective R-value after thermal bridging.

Rigid insulation

Rigid insulation is rigid board stock, polyiso, XPS, EPS, or mineral wool board, used as continuous insulation over the roof deck or outboard of the wall sheathing. It is measured in square feet of board coverage, which converts to a board count by panel size, with fasteners and adhesive carried separately. The estimator scopes it from the roof plan and wall sections, matching thickness and R-value to the spec.

Soffit

A soffit is the finished underside of a roof overhang, eave, or projecting element that closes in the space between the wall and the edge of the roof. In estimating it is taken off as square feet of underside area plus the linear-foot edge trim that frames it. Its dimensions come straight from the overhang width and the eave run length.

Storefront

Storefront is the non-residential, ground-floor aluminum framing and glass system used on retail and commercial entries, typically set in a punched or continuous opening up to about 10 ft tall. It carries the entrance doors and fixed glazing at the building face. Estimators measure it by glazed square foot of system and by count of door openings.

Threshold

A threshold is the finished sill member at the bottom of a door opening that bridges two floor finishes, seals the gap under the door, and on exterior doors sheds water. It is selected by door type and condition, such as saddle, ADA-compliant beveled, thermal-break exterior, or panic-rated. The estimator counts thresholds off the door schedule by opening, then prices each by type.

TPO roofing

TPO roofing is a single-ply thermoplastic polyolefin membrane, the most widely specified low-slope commercial roof in the US, installed in mechanically fastened, fully adhered, or induction-welded systems with heat-welded seams. It is measured in square feet and roofing squares, plus fasteners and plates or bonding adhesive. The estimator separates field membrane from flashing and accessories.

Vapor barrier

A vapor barrier in construction is a low-permeance sheet, most often polyethylene rated under ASTM E1745, installed to stop water vapor from migrating through an assembly, typically under a concrete slab on grade or behind interior gypsum in cold climates. It is measured and bid in square feet of coverage plus the lap and seam tape it takes to keep the run continuous. The estimator scopes it from the slab plan and the wall sections, not from a single dimension.

VCT (vinyl composition tile)

VCT (vinyl composition tile) is a hard, low-cost resilient floor tile made of vinyl, limestone filler, and color pigment, supplied in 12 by 12 inch squares and adhered to a prepared slab. The estimator takes it off by the square foot of floor area, then converts to tile count and to boxes for ordering. VCT is common in schools, retail back-of-house, and healthcare corridors because it is cheap and field-repairable, though it requires regular stripping and waxing.

Veneer

Veneer is a non-structural exterior cladding skin, typically brick or stone, anchored to a structural backup wall rather than carrying load. In estimating you take it off as square feet of wall face, then add the linear-foot edge work (lintels, sills, flashing) and the accessory counts. It is one of the opaque systems that make up a facade.

Window sill

A window sill is the horizontal bottom member of a window opening that supports the unit and sheds water away from the wall below. On the exterior it is often a sloped metal or stone sill with a drip; on the interior it is a stool or finished sill. The estimator counts sills off the window schedule and converts them to linear feet of sill stock for material and labor.

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.

MEP

AHU (air handling unit)

An AHU (air handling unit) in construction is the central piece of HVAC equipment that conditions and moves air through a building, packaging fans, heating and cooling coils, filters, and dampers in one casing, usually installed in a mechanical room. Estimators count AHUs each (ea) from the mechanical equipment schedule, with the unit's airflow in cfm driving the price. Unlike a packaged rooftop unit, an AHU does not generate its own cooling; it relies on chilled water or refrigerant from separate equipment.

Backflow preventer

A backflow preventer in construction is a plumbing assembly installed on a building water service to keep water from flowing backward into the public drinking supply when pressure drops or reverses. The two common commercial types are the reduced pressure zone (RPZ) assembly for high hazard connections and the double check valve assembly for lower hazard ones. Each device is counted each in the takeoff, sized to the service it protects, and in most jurisdictions must be tested by a certified tester every year.

Boiler

A boiler in construction is central plant equipment that burns fuel (usually natural gas) or uses electricity to produce hot water or steam for building heating, with capacity listed in MBH (thousands of Btu per hour) or boiler horsepower (BHP). The mechanical equipment schedule lists both input and output ratings, and the ratio between them is the boiler's efficiency. Estimators count boilers each (ea), then pick up the venting, gas piping, pumps, and trim that come with them.

Cable tray

Cable tray in construction is an open, ladder or trough shaped support system that carries runs of cables overhead, used where many circuits travel a common route, such as data centers, industrial plants, and electrical rooms. Unlike conduit, the tray supports the cables rather than enclosing them, so circuits can be added or rerouted without pulling through a closed raceway. Estimators measure cable tray in linear feet by width and type, with fittings, supports, and covers counted separately.

Cast iron pipe

Cast iron pipe in construction is a heavy, durable piping material used mainly for drain, waste, and vent (DWV) systems in commercial buildings, specified where quiet operation and fire resistance matter. Modern commercial installs are almost entirely hubless (no-hub) pipe joined with shielded couplings instead of the older hub-and-spigot joints. Estimators take it off in linear feet of pipe by diameter, with fittings and couplings counted each.

Chiller

A chiller in construction is a piece of central plant equipment that produces chilled water for a building's air conditioning system, sized in tons of refrigeration, where one ton equals 12,000 Btu per hour of cooling. Air-cooled chillers reject heat through onboard condenser fans and typically sit on the roof or a pad outside, while water-cooled chillers live in a mechanical room and reject heat through a cooling tower. On the estimate, chillers are counted each (ea) off the mechanical equipment schedule, with capacity in tons driving the price.

Circuit breaker

A circuit breaker in construction is an overcurrent protective device that automatically opens a circuit when the current exceeds its rating, protecting the conductors and equipment downstream from overloads and short circuits. Unlike a fuse, it resets instead of being replaced. In commercial buildings breakers live inside panelboards, switchboards, and switchgear, and estimators count them each (ea) from the panel schedules and the one-line diagram.

Condensate drain

A condensate drain in construction is the piping that carries the water produced by cooling equipment (the moisture that condenses on an evaporator coil) from the unit to an approved disposal point such as a hub drain or floor sink. It is taken off in linear feet of small-bore pipe, commonly 3/4 inch or larger PVC or copper, plus a trap at each unit and an air gap at the receptor. The scope sits on the seam between HVAC and plumbing, which makes it a classic bid-day gap.

Conduit

Conduit in construction is the pipe or tubing that protects and routes electrical wiring between panels, junction boxes, and devices. The common commercial types are EMT (thin wall steel tubing), rigid metal conduit (RMC), intermediate metal conduit (IMC), and PVC, selected by exposure and location. Estimators take conduit off in linear feet by size and type, and the fittings, supports, and conductors all follow from that footage.

Copper pipe types

Copper pipe types in construction are the wall thickness grades of copper tube: Type K (thickest wall), Type L (medium), and Type M (thinnest), all sharing the same outside diameter for a given nominal size. Type L is the workhorse for domestic water piping in US commercial buildings, Type K serves underground water service, and Type M is limited to lighter duty work where the local code allows it. The type changes the price per foot and the spec compliance, not the fittings.

Damper

A damper in construction is a movable plate or set of blades inside ductwork that regulates, shuts off, or blocks airflow. The common types on commercial projects are manual balancing dampers at branch ducts, motorized control dampers at outside air and relief openings, and life safety fire dampers and smoke dampers at rated wall and floor penetrations. Estimators count dampers each (ea), broken out by type and duct size, because the installed costs differ widely.

Diffuser

A diffuser in construction is the finished air outlet, usually ceiling mounted, that distributes supply air from the ductwork into a room in a controlled pattern. Diffusers, registers, and grilles are counted each (ea) in the takeoff, with the count pulled from the reflected ceiling plan and verified against the mechanical air device schedule. Each count carries an assembly behind it: the device, the flex duct runout, the balancing damper, and the labor to set and connect it.

Duct

A duct in construction is the sheet metal (or occasionally fiberglass or fabric) passage that moves supply, return, and exhaust air between HVAC equipment and the spaces it serves. In commercial estimating, ductwork is taken off in pounds of sheet metal or square feet of duct surface, computed from the duct dimensions, the metal gauge, and the run length. It is the core of the sheet metal contractor's scope and usually the biggest line in the mechanical bid after the equipment itself.

Duct insulation

Duct insulation is the thermal and acoustic material applied to HVAC ductwork, either as external wrap (foil faced fiberglass blanket installed in the field) or internal liner (fiberglass board installed inside the duct at the fabrication shop). It is taken off in square feet of duct surface, driven by the duct perimeter times the run length plus the wrap's added thickness. The energy code and the mechanical insulation schedule dictate which ducts get covered, at what R-value, and whether wrap or liner is specified.

Ductwork gauge

Ductwork gauge is the thickness of the sheet metal a duct is fabricated from, named on a scale where a lower number means thicker steel: 18 gauge is heavier than 26 gauge. Gauge matters to the estimate because sheet metal duct is priced by weight, and a heavier gauge means more pounds for the same square feet of duct surface. SMACNA duct construction standards set the minimum gauge from the duct's pressure class and its largest dimension.

DWV (drain waste vent)

DWV in construction stands for drain, waste, vent: the sanitary piping system that carries wastewater out of a building by gravity and vents sewer gases through the roof. Drain and waste lines fall continuously toward the building sewer, while vent lines admit air so traps keep their water seal. Estimators take DWV off in linear feet by pipe size and material, plus fitting counts, with underground and aboveground runs kept separate.

EMT conduit

EMT conduit (electrical metallic tubing) is thin wall steel tubing used to route and protect wiring in interior commercial construction, joined with set screw or compression fittings instead of threads. It is the workhorse raceway of US commercial interiors because it is light, fast to bend, and far cheaper to install than rigid conduit. Estimators measure EMT in linear feet by trade size, with the size driven by how many conductors the run must carry.

Fire alarm

A fire alarm system in construction is the low-voltage detection and notification network, smoke detectors, pull stations, horn/strobes, and a fire alarm control panel (FACP), that senses fire and alerts occupants and the monitoring service. It is designed to NFPA 72 and installed by a licensed fire alarm or electrical subcontractor. In a takeoff, devices are counted each by type off the FA plans, and the wiring between them is measured in linear feet.

Fire sprinkler

A fire sprinkler in construction is an automatic discharge head connected to a piped water network that opens individually when its heat-sensitive element reaches its rated temperature, putting water directly on the fire below it. Commercial systems are designed to NFPA 13, which sets coverage area per head and water density by the hazard classification of the space. In a takeoff, heads are counted each, pipe runs in linear feet, and the work is usually bought as a design-build fire protection subcontract.

Fixture unit

A fixture unit in construction is a code-assigned load value, not a physical object: it represents the demand a plumbing fixture places on the water supply system (water supply fixture units, WSFU) or the drainage system (drainage fixture units, DFU). Engineers sum fixture units along each pipe run and use code tables to convert the total into a pipe size. A lavatory might carry 1 DFU while a flushometer water closet carries 4, so the same branch line grows as fixtures accumulate upstream of it.

Gas piping

Gas piping in construction is the fuel gas distribution system that carries natural gas or propane from the utility meter to appliances such as water heaters, boilers, rooftop units, and kitchen equipment. It is sized from the connected BTU load and the length of the run, and installed mostly in black steel pipe or CSST. In a takeoff, pipe is measured in linear feet by size, while meters, regulators, and valves are counted each.

GFCI

A GFCI, or ground fault circuit interrupter, is an electrical protective device that compares the current leaving on the hot conductor with the current returning on the neutral and shuts the circuit off when they differ, meaning current is leaking to ground, possibly through a person. The National Electrical Code requires GFCI protection in locations such as bathrooms, kitchens, outdoors, and near sinks. In a takeoff, GFCI receptacles are counted each and carry a price premium over standard receptacles.

Grease trap

A grease trap in construction is a plumbing device that intercepts fats, oils, and grease (FOG) from kitchen waste lines before they reach the sanitary sewer, where they would congeal and block the pipe. Small hydromechanical units rated in gallons per minute sit at or near the fixtures; large gravity grease interceptors, in-ground tanks rated in gallons, serve full commercial kitchens. Estimators count them each, and food service projects almost always carry one because the local sewer authority requires it.

Heat pump

A heat pump in construction is HVAC equipment that moves heat rather than generating it, using a refrigeration cycle that can reverse to provide both heating and cooling from one machine, with capacity sized in tons (12,000 Btu per hour each). The three common families are air-source (heat exchanged with outdoor air), water-source (heat exchanged with a building water loop), and ground-source (heat exchanged with the earth through a buried loop or wellfield). On commercial takeoffs they are counted each (ea) from the mechanical schedule, often in large quantities of small units.

Hydronic piping

Hydronic piping in construction is the piping that circulates water for heating and cooling: chilled water (CHW) from the chiller to cooling coils, heating hot water (HHW) from the boiler, and condenser water (CW) between the chiller and the cooling tower. It is taken off in linear feet (lf) by pipe size, material, and service, with insulation, valves, hangers, and specialties carried as follow-on lines. On the drawings it lives on the mechanical piping plans and riser diagrams.

Junction box

A junction box in construction is an enclosed metal or nonmetallic box where electrical conductors are spliced, pulled, or tapped, keeping every connection protected and accessible as the National Electrical Code requires. On commercial projects most junction boxes are never drawn individually; they follow the conduit runs, so estimators count them as each (ea) by size and type, derived from the routing rather than read straight off the plans. Common types are 4 in square boxes on branch circuits and larger dimensioned pull boxes on feeders.

Lighting fixture

A lighting fixture in construction is a complete lighting unit, the housing, LED array or lamp, driver, and lens, installed and counted as one item. The formal term on specifications and schedules is luminaire, but field and estimating usage says fixture. Fixtures are counted each by type tag (Type A, Type B, and so on) from the fixture schedule and the lighting plans, and each type carries its own unit cost.

Low voltage

Low voltage in construction refers to the cabling, devices, and head end equipment for systems that do not run on line voltage power: data networks, security and access control, audiovisual, building controls, and fire alarm. It is usually a separate scope from the electrical contract, carried by one or more specialty subcontractors, and estimators count it in drops and devices (ea) plus linear feet of cable. On the drawings it lives on technology, security, and fire alarm sheets rather than the power plans.

MC cable

MC cable (metal clad cable) is a factory assembled wiring product with insulated conductors and a grounding conductor inside a flexible interlocking metal armor, used to wire branch circuits without installing conduit and pulling wire separately. Estimators measure it in linear feet (lf) by conductor configuration, such as 12/2 or 12/3. Choosing MC over conduit and wire is a means and methods decision that can swing branch wiring labor significantly, so estimators often price both where the spec allows a choice.

Panelboard

A panelboard in construction is a wall-mounted electrical distribution assembly that accepts one incoming feeder and splits it into branch circuits, each protected by its own circuit breaker. It is the gray box behind a hinged door in an electrical room or corridor wall, commonly a 42-circuit, 208Y/120V panel in US commercial work. Estimators count panelboards each (ea) from the one-line diagram and panel schedules, then price the breakers, feeder, and connections that go with each one.

PEX

PEX in construction is cross-linked polyethylene tubing, a flexible plastic pipe used for domestic hot and cold water distribution and hydronic heating. It comes in coils and straight lengths, installs with expansion, crimp, or push fittings rather than soldered joints, and is taken off in linear feet by size, just like copper. The choice between PEX and copper is a material decision that changes the price per foot, the fitting system, and the labor hours.

Plumbing rough-in

Plumbing rough-in in construction is the phase where all the in-wall, overhead, and underground piping is installed before walls close and fixtures set: the drain, waste, and vent (DWV) lines, the hot and cold water distribution, and the stub-outs each fixture will connect to. It happens in two passes, an underground rough before the slab pours and an above ground rough (top-out) after framing, each inspected and pressure tested before cover. Estimators commonly shorthand its cost per fixture.

Raceway

A raceway in construction is any enclosed channel designed to hold and route wires and cables, a National Electrical Code umbrella term that covers conduit (EMT, RMC, IMC, PVC), surface raceway, wireway, and underfloor duct. Every conduit is a raceway, but not every raceway is conduit. Estimators take raceway off in linear feet by system type and size, since each system carries its own material and labor cost.

RCP (reflected ceiling plan)

An RCP, or reflected ceiling plan, is a construction drawing that shows the ceiling of each room as if a mirror lay on the floor reflecting everything above it. The mirror convention keeps the ceiling layout in the same orientation as the floor plan, so north stays north and the walls line up sheet to sheet. Estimators use the RCP to take off ceiling grid areas, lighting fixture counts, diffuser and grille locations, and ceiling heights.

Receptacle

A receptacle in construction is the contact device installed at an outlet for plugging in cord-connected equipment, what most people call an electrical outlet, typically a 120 V duplex on US commercial jobs. Estimators count receptacles each (ea) from the power plans, with standard duplex, GFCI, isolated ground, and floor box receptacles carried as separate line items because their installed costs differ sharply.

Refrigerant piping

Refrigerant piping in construction is the ACR copper line set that carries refrigerant between the outdoor unit and the indoor coil of an air conditioning or heat pump system, made up of a small liquid line and a larger, insulated suction line. Estimators take it off in linear feet per circuit, pulling the line sizes from the equipment manufacturer's tables rather than scaling them off the drawings. The joints are brazed, and the work belongs to the mechanical contractor's piping scope.

RTU (rooftop unit)

An RTU (rooftop unit) in construction is a packaged HVAC unit installed on the roof that contains its own compressors, condenser, fans, and heating section in one factory-built cabinet, supplying conditioned air directly into the building's ductwork. Estimators count RTUs each (ea) from the mechanical equipment schedule, with cooling capacity in tons driving the equipment price. Unlike an indoor air handling unit, an RTU is self-contained: it needs only a roof curb, power, gas (if gas heat), and duct connections.

Smoke damper

A smoke damper in construction is a life-safety device mounted in ductwork where it penetrates a smoke barrier, driven closed by an actuator on a signal from a duct detector or the fire alarm system so smoke cannot travel through the duct. Estimators count smoke dampers each (ea), and every one drags an actuator, an access door, and often a duct smoke detector along with it. Many rated wall locations use combination fire/smoke dampers that respond to both heat and smoke.

Standpipe

A standpipe in construction is a vertical fire protection riser, usually running up a stair tower, with hose connections at each floor so firefighters or occupants can fight a fire without dragging hose up from the street. NFPA 14 defines three classes: Class I provides 2.5 inch hose connections for fire department use, Class II provides 1.5 inch hose stations for occupant use, and Class III provides both. In a takeoff, the riser is measured in linear feet and the hose valves are counted each, floor by floor.

Sump pump

A sump pump in construction is a pump set in a pit, called a sump basin, at the low point of a basement, elevator pit, or foundation drainage system, where it collects groundwater and lifts it up to a storm drainage point. Commercial installations are commonly duplex, two pumps in one basin with a control panel and high water alarm, so one pump can fail without flooding the space. Estimators count the pump each, but the priced scope is the whole assembly: basin, check valves, discharge piping, and controls.

Switchgear

Switchgear in construction is the heavy, free-standing electrical distribution equipment at the top of a building's power system: an assembly of vertical sections housing the main and feeder circuit breakers, bussing, and metering. In commercial estimating the word matters because switchgear, switchboards, and panelboards are different products at very different price points and lead times. Estimators count switchgear each (ea), or per lineup, from the one-line diagram.

Transformer

A transformer in construction is electrical distribution equipment that changes voltage between systems, most commonly stepping a commercial building's 480V distribution down to 208Y/120V for receptacles and general loads. Transformers are rated in kilovolt-amperes (kVA), with 75 kVA dry-type units among the most common in US commercial work. Estimators count them each (ea) from the one-line diagram, where every transformer appears with its kVA rating and its primary and secondary voltages.

VAV box

A VAV box (variable air volume box) in construction is a sheet metal terminal unit installed in the ductwork that regulates how much conditioned air flows to a zone, opening and closing an internal damper in response to the zone thermostat. Estimators count VAV boxes each (ea) from the mechanical equipment schedule, sized by design airflow in cfm, with or without a reheat coil. The boxes sit between the main supply duct and the diffusers serving each zone.

VRF system

A VRF system (variable refrigerant flow) in construction is a heat pump HVAC system that links one or more outdoor units to many indoor fan coil units through a network of refrigerant piping, modulating refrigerant flow to each zone instead of pushing all the air through central ductwork. Heat recovery versions add branch controllers so some zones can heat while others cool at the same time. For an estimator, a VRF job is a component count cascade: every indoor unit pulls a line set, a condensate drain, and a controller in behind it.

Water heater

A water heater in construction is the plumbing equipment that produces a building's domestic hot water, supplied either as a storage tank unit or a tankless on-demand unit, fueled by gas or electricity. On commercial projects it appears on the plumbing equipment schedule and is counted each in the takeoff. The unit itself is only part of the scope: venting, gas piping, electrical connections, drain pans, expansion tanks, and condensate drains follow every heater.

Sitework

Aggregate base

Aggregate base in construction is a compacted layer of crushed stone placed under asphalt, concrete pavement, curbs, and sidewalks to spread wheel loads into the subgrade and provide a stable, drainable platform for paving. Estimators take it off as area times depth, carrying square yards (sy) for placement and cubic yards (cy) or tons for material. The pavement section detail calls out the stone class and a compaction requirement, commonly 95 percent of maximum density.

Asphalt paving

Asphalt paving in construction is the placement of hot mix asphalt in compacted lifts over a prepared aggregate base to build parking lots, drives, and roadways. It is bought and priced per ton, and estimators convert measured area to tonnage using the common rule of thumb of about 110 pounds per square yard per inch of thickness. A typical commercial section places a coarser base course lift first, then a finer surface course lift over it.

Backfill

Backfill in construction is the soil or aggregate placed back into an excavation after foundations, walls, or utility pipe are installed, then compacted in lifts to a specified density. Estimators split it into structure backfill (around foundations and walls) and trench backfill (over utility lines) and price it per compacted cubic yard. The material is either native soil reused from the excavation or imported select fill when the geotech report disqualifies the native material.

Catch basin

A catch basin in construction is a precast concrete inlet structure with a grate on top that collects surface runoff and feeds it into the storm drain system, with a sump below the outlet pipe to trap sediment. Estimators count catch basins each (ea), grouped by depth class, because the vertical feet from rim to invert drive the price more than anything else. Each one appears on the civil utility and grading plans with a rim elevation and invert elevations for its pipe connections.

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

Blocking

Blocking is short pieces of framing lumber cut and installed between studs, joists, or rafters to brace the frame, fill gaps, back up finishes, or stop fire and air movement. It is the same dimension lumber as the members it sits between and is taken off in linear feet. Fire blocking, solid blocking for structural bracing, and nailer blocking for finishes are common types.

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.

Cripple stud

A cripple stud is a short vertical stud that fills the framing gap above a header or below a window sill in a wall opening. It is not full height because the opening interrupts the wall, but it still carries load and maintains stud layout so sheathing and finishes have continuous backing. Cripples are cut from the same stock as the wall studs and held to the same on-center spacing.

Fire blocking

Fire blocking is solid material installed inside concealed framing cavities to cut off the vertical and horizontal pathways that let fire and hot gases spread through a building. In light-frame work it is typically a 2x stud-width block of dimensional lumber, though mineral wool, fire-rated foam, or other approved materials also qualify. Code dictates where it goes; the estimator counts the linear feet and penetrations.

Furring

Furring is the practice of fastening thin strips of wood or metal, called furring strips, to a wall, ceiling, or structural surface to create a level, spaced framing plane for finishes. Furring gives drywall, paneling, or cladding something to attach to while leaving an air gap, correcting an uneven surface, or holding insulation. The strips are typically 1x2 or 1x3 wood or hat-channel metal run at 16 in or 24 in on center.

Glulam (glued laminated timber)

Glulam (glued laminated timber) is an engineered beam made from individual dimensional lumber laminations glued and stacked with the grain running lengthwise, used for long-span beams, ridge beams, and exposed architectural members. In framing it carries spans and loads beyond what sawn lumber or smaller engineered members can handle, and it can be left exposed as finish.

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.

Hurricane tie

A hurricane tie is a galvanized metal framing connector that fastens a rafter or truss to the top plate or wall below, resisting the uplift and lateral forces that wind puts on a roof. It creates a continuous load path from the roof down into the wall. Quantity is a straight count, typically one tie at each rafter or truss bearing point.

I-joist

An I-joist is an engineered floor or roof framing member shaped like a capital I, with solid sawn or LVL flanges top and bottom and a thin OSB or plywood web between them. In framing it replaces dimensional joists for longer, straighter, lighter floor spans with consistent depth and no crown.

Jack stud (trimmer)

A jack stud, also called a trimmer, is a shortened wall stud that runs from the bottom plate up to the underside of a header and carries the header's load down to the floor. It is nailed to the full-height king stud beside it. Jack studs are what actually hold up everything bearing on the opening, so their count and length matter on every door and window.

Joist

A joist is a horizontal framing member, usually 2x lumber or an engineered member, that supports a floor or ceiling by spanning between bearing walls or beams. Floor joists are sized by their span and spaced at 16 in or 24 in on center to carry the subfloor and the loads above.

King stud

A king stud is a full-height stud that runs continuously from the bottom plate to the top plate on each side of a wall opening, framing the opening and anchoring the header assembly. King studs are nailed to the jack studs that carry the header, and together they form the structural edges of a door or window opening. They are cut from the same stock as the field studs, typically 2x4 or 2x6.

LVL (laminated veneer lumber)

LVL (laminated veneer lumber) is an engineered structural member made from thin wood veneers glued together with the grain running the same direction along the length, used for beams, headers, and rim board. In framing it carries heavy point and uniform loads where dimensional lumber would be undersized or unavailable in the needed length.

Nominal vs actual lumber dimensions

Nominal lumber size is the name a board is sold under, like 2x4, while the actual size is the finished dimension after milling and drying, 1.5 in x 3.5 in for that 2x4. The difference comes from surfacing the rough sawn board smooth and shrinkage during drying. Estimators must use actual dimensions for layout and clearances, even though they order by nominal.

OSB (oriented strand board)

OSB (oriented strand board) is an engineered wood panel made from compressed wood strands bonded with resin, used as structural sheathing for walls, roofs, and subfloors in light-frame construction. It performs the same structural job as plywood at a lower cost, which is why it dominates wall and roof sheathing on most US framing jobs.

Plywood grades

Plywood grades are the stamped letter ratings (A, B, C, D) that describe the veneer face quality on each side of a structural plywood panel, paired with an exposure rating and span rating. In framing, the grade tells you whether a panel is meant for hidden structural sheathing or for a finished, visible surface.

Rafter

A rafter is a sloped structural framing member that runs from the ridge or wall plate down to the eave, carrying the roof deck and loads in a stick-framed roof. Rafters are spaced at a set on-center dimension, usually 16 in or 24 in, and cut to length along the roof pitch. They are the field-built alternative to manufactured trusses.

Rim joist (band joist)

A rim joist, also called a band joist, is the joist that runs around the outside edge of a floor frame, capping the ends of the floor joists and closing the perimeter. It sits on the sill plate or top plate and ties the floor system together. Its quantity is simply the floor perimeter in linear feet plus waste.

Sheathing

Sheathing is the structural panel skin applied over wall studs and roof rafters or trusses to brace the frame and provide a nailing base for cladding and roofing. It is almost always 4 ft by 8 ft OSB or plywood, taken off in square feet and converted to a sheet count. Wall and roof sheathing are estimated separately because thickness and waste differ.

Sill plate

A sill plate, also called the mudsill, is the bottom horizontal member of the frame that sits directly on top of the foundation wall or slab and anchors the building to it. It is pressure-treated lumber bolted down with anchor bolts and is the first piece of wood the framer sets. The takeoff is the linear feet of foundation perimeter plus the anchor bolt count from the bolt spacing.

Sleeper

A sleeper is a strip of dimensional lumber laid flat on a concrete slab to create a raised, fastenable framing base for a subfloor or finish flooring. Sleepers level out the slab, hold an air and insulation gap, and keep wood flooring off the concrete. They are commonly 2x4 stock run at 16 in on center and anchored to the slab.

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.

Subfloor

Subfloor is the structural sheathing layer, usually tongue-and-groove plywood or OSB panels, fastened across the floor joists to form the walking surface and the base for finish flooring. It spans joist to joist and ties the floor frame into a stiff diaphragm. Quantity is the floor area in square feet converted to 4x8 sheets plus waste.

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.

Truss

A truss is a pre-engineered, factory-built roof or floor frame made of dimensional lumber webs and chords connected by metal plates, delivered ready to set. In roof framing it replaces stick-built rafters and ceiling joists with a single component spanning wall to wall. Trusses are spaced at a set on-center dimension and counted off the truss layout.

Stop looking terms up. Start pricing bids faster.

Ruh reads your drawings, does the takeoff, and prices it on your own price book.

Book a Demo Talk to Sales