Construction estimating glossary: The words on an estimate, defined plainly.
25 terms that come up on bid documents and estimates, with the UK equivalent where the words differ and a link to a longer explanation where one exists. For the wider differences between the two markets, see US and UK estimating conventions.
- Addendum
- A formal change to the bid documents issued before bids are due. An addendum can add, replace or withdraw drawing sheets and specification sections, so an estimate is only valid for the addenda it lists.
- Read more: What to send an estimator
- AllowanceUK: provisional sum
- A sum carried for work that is known to be needed but is not yet defined enough to measure, such as a finish that has not been selected. Allowances should be totalled separately so it is clear how much of an estimate is a placeholder.
- Read more: How to read an estimate
- Assembly
- A group of items priced together as one unit, for example a square foot of a particular wall type including studs, board, insulation and finish. Assemblies are fast to price with but hide specification changes unless each one records what it contains.
- Read more: Construction estimating methods
- Bank, loose and compacted volume
- The three volumes the same soil occupies: undisturbed in the ground, bulked up after excavation, and after placing and compaction. Excavation is priced in bank volume, haulage in loose volume and fill in compacted volume.
- Read more: Swell, shrink and earthwork volumes
- Bid levellingUS: bid leveling
- Adjusting subcontractor or supplier quotes to a common scope so they can be compared fairly. Quotes that look close on price often cover different inclusions and exclusions.
- Read more: Bid validation and sub-bid levelling
- Bill of quantities
- A UK tender document listing measured quantities of work, usually prepared to a standard method of measurement such as NRM2, so every bidder prices the same quantities.
- Read more: Quantity takeoff vs material takeoff
- Bonds
- Surety guarantees included in a bid build-up. A bid bond backs the bidder’s commitment to sign the contract; performance and payment bonds guarantee completion of the work and payment of subcontractors and suppliers. They are commonly required on public work.
- Change orderUK: variation
- A formal change to the contract scope, price or time after award. A change order is only defensible when it is priced on the same basis as the original estimate, with omitted work credited as well as added work charged.
- Read more: Change order pricing
- Contingency
- An amount carried for risk inside the defined scope, such as quantity uncertainty or pricing movement. It is not a fund for scope changes, which are priced separately as change orders.
- CSI MasterFormat
- The standard for organising construction specifications and cost information into numbered divisions, published by the Construction Specifications Institute and Construction Specifications Canada. Division 03 is concrete, 26 is electrical, 31 is earthwork. Most US estimates are structured by these divisions.
- Read more: Trades by CSI division
- Elemental cost plan
- A cost estimate grouped by functional building element, such as substructure, frame, roof and services, rather than by trade. It is the standard cost-planning approach in the UK, where it commonly follows RICS NRM1.
- Read more: Construction estimating methods
- General conditionsUK: preliminaries
- Project costs not tied to a single trade: supervision, site facilities, temporary works, insurance, cleaning and similar. They are time-related, so they should be priced against the programme duration rather than taken as a percentage.
- Read more: Commercial construction estimating
- Labour burden
- The employer costs added to a bare wage: payroll taxes, insurance, holiday, pension and benefits. Burden commonly adds a substantial percentage to the cost of an hour and should be shown separately from the wage.
- Read more: Labour: hours, not lump rates
- Material takeoffMTO
- Measured quantities converted into purchase units, such as sheets, stock lengths, bags and boxes, with laps, waste, rounding and accessories included. It is the list a supplier or buyer orders from.
- Read more: Material takeoff services
- Overhead and profitO&P
- The markup added to direct cost to cover the business’s own overhead and its return. It is usually applied as a percentage in the bid build-up, and it matters which lines it is applied to.
- Planswift
- On-screen takeoff software used to measure areas, lengths and counts directly on digital drawings. Measured items are marked on the sheet in colour, which lets a quantity be traced back to the drawing it came from.
- Read more: Quantity takeoff services
- Production rate
- The labour hours needed to install one unit of work, such as hours per square foot of board or per cubic yard of footing. Multiplied by the quantity and the crew wage, it gives labour cost, and it can be adjusted for height, access and repetition.
- Read more: Labour: hours, not lump rates
- Quantity takeoffQTO
- The measurement of every item of work shown on the drawings, in the unit it is installed in: square feet, linear feet, cubic yards, each. It is the foundation of every estimate and does not include pricing.
- Read more: Quantity takeoff services
- RFI
- Request for information: a formal question to the design team where the drawings or specification are unclear or conflict. Items that cannot be priced without an answer should be listed in the estimate rather than guessed.
- Schedule of values
- A breakdown of the contract sum by work item or division, used in the US as the basis for progress billing. An estimate organised by CSI division reconciles against it directly.
- Scope gap
- Work that falls between packages, so no one prices it, or that sits in two packages, so it is priced twice. Scope gaps usually occur at trade boundaries and are closed by writing down where each package stops.
- Read more: Nine takeoff mistakes
- Swell and shrinkage factors
- Percentages that convert soil between bank, loose and compacted volume. Swell governs truck loads and haulage; shrinkage governs whether a site that balances on paper will need imported fill.
- Read more: Earthwork estimating
- Unit cost
- The cost of one unit of measured work, built from its labour, material and equipment. A unit-cost estimate measures and prices every item individually and needs construction documents to be meaningful.
- Read more: Construction cost estimating
- Value engineering
- Reviewing a design for alternatives that deliver the same function at lower cost. It only works when each alternative is priced against the base scheme, including knock-on costs in other divisions.
- Read more: Value engineering support
- Waste factorWastage
- The percentage added to a measured material quantity for cutting loss and purchase rounding. It varies widely by material and geometry, applies to material only and never to labour, and belongs in its own column.
- Read more: Waste factors by material
Every term above shows up in our deliverable.
Production rates, waste columns, allowances totalled separately and a bid build-up with each markup on its own line. The sample shows all of it.
Fixed project fees · US and UK · Unlimited revisions within scope