A quantity is meaningless without a rule that defines it. Whether an opening is deducted, whether a wall is measured to the underside of slab, whether excavation is measured net or with working space — these are conventions, and different conventions produce different numbers from the same building.
Standard methods of measurement exist so that every party pricing a project measures the same thing. Firms working across US, UK, and Australian markets encounter several, and treating them as interchangeable produces bids that are not comparable.
The RICS New Rules of Measurement
The NRM suite, published by RICS, covers the cost management lifecycle in three parts.
NRM 1 — Order of cost estimating and cost planning for capital building works. Governs early-stage estimating and cost planning, structured elementally. It defines what a cost plan contains at each stage, how elements are grouped, and how the estimate develops from a cost per square metre through to elemental cost planning.
Its elemental structure — substructure, superstructure with its sub-elements, internal finishes, fittings, services, external works, and so on — is the framework behind most UK benchmarking data, which is why alignment to it makes cost comparison meaningful.
NRM 2 — Detailed measurement for building works. The rules for producing bills of quantities and quantified schedules of works. It defines, for each work section, the unit of measurement, what is deemed included in a rate, what must be measured separately, and the level of description required.
The "deemed included" provisions are the substance. When a rate for concrete is deemed to include a specified list of items, a contractor pricing it knows precisely what is covered. Departing from that list without stating so is where measurement disputes originate.
NRM 3 — Order of cost estimating and cost planning for building maintenance works. Extends the same logic to whole-life and maintenance cost, which matters increasingly on projects with life-cycle cost requirements or long-term operational commitments.
CESMM for civil engineering
The Civil Engineering Standard Method of Measurement, now in its fourth edition, serves civil and infrastructure work, where the measurement problems differ substantially from building work.
Its distinguishing features:
A structured item coding system. Each item is coded by class and by up to three divisions, producing a systematic reference that identifies exactly what is being measured. The coding makes large bills navigable and comparable.
Explicit treatment of earthworks. Excavation, disposal, filling, and compaction have detailed rules covering material classification, depth ranges, and disposal destination — the areas where civil quantities are most volatile.
Method-related charges. CESMM allows the contractor to price time-related and fixed charges separately from measured work. This is a significant conceptual difference from building measurement and reflects the reality that on civil work, plant standing time and site establishment are often larger cost drivers than the measured quantities.
Infrastructure work in the UK also encounters the Method of Measurement for Highway Works on road schemes, and various sector-specific standards in rail and water.
POMI and international work
The Principles of Measurement (International) provides a simplified, internationally portable measurement framework, widely used in the Middle East and in international projects where no local standard is mandated. It is less prescriptive than NRM 2, which makes it more adaptable and correspondingly more dependent on well-written preambles.
What US and Australian practitioners should know
The United States has no single mandated method of measurement equivalent to NRM. Estimating practice is structured around CSI MasterFormat for specification and work-result organization, and UniFormat for elemental estimating. Quantities are measured by convention within trades, and bills of quantities are far less common — most US work is priced from drawings and specifications rather than from a measured bill.
The practical consequence for a US firm bidding UK work is that the bill of quantities is a contract document with defined measurement rules, not a convenience. Rates apply to quantities measured a specific way, and remeasurement provisions matter.
Australia uses the Australian Standard Method of Measurement of Building Works, produced jointly by the industry bodies, with a structure recognizable to anyone familiar with the UK lineage. Australian practice sits between the two: more use of bills than the US, less prescriptive than NRM 2 in some sections.
Why the standard matters to a takeoff
Concretely, the same building measured under different rules produces different quantities. Common divergences:
- Deduction thresholds for openings. Some rules deduct all openings; others deduct only those above a stated area.
- Measurement boundaries. Wall areas measured to structural soffit or to finished ceiling; floor finishes measured to wall face or through partitions.
- Working space in excavation. Measured or deemed included, depending on the standard.
- Formwork. Measured separately by face area, or deemed included in the concrete rate.
- Laps and waste in reinforcement and finishes. Included in measured quantity or priced within the rate.
A takeoff produced without knowing which rule set applies is not usable for pricing a bill. This is the single most important instruction to give any measurement partner, and it should appear at the top of the brief.
Producing bills that price cleanly
Regardless of standard, bills that receive consistent pricing share characteristics:
Complete preambles. Stating the measurement standard, the edition, and any departures from it. Departures are permitted; undisclosed departures are not.
Adequate item descriptions. Sufficient for a contractor to price without inference. Under-described items are priced with risk margin, which costs the client more than the description would have.
Provisional sums clearly identified, with the basis stated and what they cover defined.
Consistent structure aligned with how the work will be procured, so packages can be extracted without re-measurement.
A clear risk allocation on remeasurable items, so contractors know which quantities are firm and which will be adjusted.
Writing preambles that carry their weight
The preambles are the part of a bill nobody reads until there is a dispute, at which point they decide it. Preambles worth writing state:
- The measurement standard and its edition, precisely
- Every departure from it, itemised
- The definitions of terms used inconsistently across the industry — "provisional", "approximate quantity", "provisional sum", "prime cost"
- Which quantities are firm and which are remeasurable
- The treatment of items deemed included where the standard is silent
- The basis on which contractors should price risk items
The single most valuable line in most preambles is the one stating what happens when the drawings and the bill disagree. Without it, every discrepancy becomes a negotiation.
Practical guidance for firms working across markets
A firm bidding or measuring across US, UK, and Australian projects should hold three things in place.
A measurement rule library. For each standard the firm works under, a documented set of the rules that most commonly differ — opening deductions, measurement boundaries, formwork treatment, working space, and lap and waste conventions. Measurers reference it rather than remembering it.
A model-to-measurement mapping per standard. Where quantities are extracted from models, the mapping differs by standard because the rules differ. Maintaining one mapping and using it everywhere produces quantities that are wrong in a different way in each market.
A review step by someone who works in that market routinely. Measurement conventions carry a great deal of unwritten practice, and a review by someone fluent in the local convention catches what documentation does not cover.
Firms that treat measurement as a portable skill and standards as interchangeable produce bills that price inconsistently, and they discover it through tender returns that vary far more than the market should explain.
Frequently asked questions
Which standard should an international project use? Whichever the contract specifies. Where the choice is open, use the standard familiar to the market the contractors come from — the goal is comparable pricing, and unfamiliar rules produce inconsistent risk pricing.
Can quantities measured under one standard be converted to another? Partially, with adjustment for the known differences. It is rarely economical for anything beyond a spot check; re-measurement is usually faster and safer.
Do model-based quantities satisfy NRM 2? Only after reconciliation. Extracted geometry follows modeling convention, not measurement rules, and the mapping between them must be explicit.
Related reading: Estimate Classes Explained: From Order of Magnitude to Definitive · Quantity Takeoff: Manual, Digital, and Model-Based Compared · 5D BIM: Linking Cost to the Model Without Losing Control
Vantage CAD Services produces quantity takeoff and bills of quantities to NRM, CESMM, POMI, and Australian standards for firms working across multiple markets. Contact info@vantagecadservices.com or +1 (512) 543-0831.