NRM2 Estimating Standards Guide
Two estimators, same drawings, same project. One comes back at £840,000. The other comes back at £897,000. Nobody made an arithmetic mistake. They measured the concrete frame differently, one by NRM2's thickness and orientation bands, one by an older habit, and the gap compounded across every trade on the bill. That's the entire reason NRM2 (New Rules of Measurement 2) exists: a shared rulebook for how quantities get measured, described and billed, so two Bills of Quantities on the same job land in the same place.
Key Takeaways
- NRM2 has three parts: general definitions, rules for detailed measurement, and tabulated measurement rules split across 41 numbered work sections.
- Published by RICS and operative since January 2013, NRM2 replaced SMM7 within six months, by 1 July 2013 SMM7 was no longer the reference standard for new UK projects.
- Description quality decides tender accuracy more than measurement technique. Vague item descriptions, not measurement errors, cause most BoQ disputes.
- MEP builderswork boundaries, provisional sums versus provisional quantities, and interface gaps between trades are the three places NRM2 BoQs go wrong most often.
- A properly built NRM2 bill reconciles back to the NRM1 cost plan, giving a genuine control point rather than two disconnected documents.
The three parts of NRM2
NRM2, published by RICS and operative since January 2013, splits into three parts. Part 1, General, sets the definitions and symbols and places measurement in context against the RIBA Plan of Work and the OGC Gateway process. Part 2, Rules for Detailed Measurement, covers the purpose of a Bill of Quantities, work breakdown structures, and how the bill feeds cost management, not just pricing. Part 3, Tabulated Rules of Measurement, is the part estimators live in day to day: the actual measurement rules, organised by trade and element across 41 numbered work sections running from preliminaries through demolition, groundworks, concrete, masonry, timber, finishes, and mechanical and electrical services.
| NRM2 Part | What it does | Who uses it most |
|---|---|---|
| Part 1: General | Definitions, symbols, project stage context | Set-up, before take-off begins |
| Part 2: Rules for Detailed Measurement | BoQ purpose, structure, cost management links | Estimators structuring the bill |
| Part 3: Tabulated Rules | The 41 work sections, item by item | Day-to-day take-off and pricing |
What actually changed from SMM7
NRM2 dropped SMM7's letter-based sections (A through Y) entirely and moved to 41 numbered work sections. That's a structural change, not just a relabelling. It also cut the old dependency on Co-ordinated Project Information references, which most estimators under 40 have never actually used.
The measurement principles moved too. In-situ concrete now gets classified by thickness band, above or below 300mm, and by orientation, horizontal, sloping or vertical, instead of the older SMM7 categories. Structural metalwork sits in new weight bands: under 25kg, 25 to 50kg, 50 to 100kg, over 100kg. Excavation depth staging simplified to flat two-metre increments rather than the finer SMM7 gradations. A batch of items that used to appear as their own bill lines, spacers, chairs, mortices, now sit deemed included inside the main item.
None of that is trivia. Price a job against SMM7 habits applied to an NRM2 bill and your rates won't match the item content, because the item boundaries themselves moved. If you're comparing this project against the wider regulatory picture, our UK construction standards and regulations guide covers how NRM2 sits alongside Building Regulations and CDM 2015.
Most BoQ disputes trace back to a vague description, not a measurement error.
NRM2 by trade: three worked examples
Generic explanations of NRM2 stop at the rulebook. Here's how it plays out on real trades.
Groundworks and excavation
NRM2 bills excavation in flat two-metre depth stages. A basement dig at 3.4m sits in the 2 to 4m band, priced as a single stage rather than broken into finer increments. Miss that banding and your excavation rate undercounts the plant time and disposal cost for the deeper stage, a common gap on basement and self-build jobs.
Concrete frame
A suspended slab measured under NRM2 splits by thickness (above or below 300mm) and orientation. A 250mm suspended slab and a 350mm suspended slab are two different bill items even on the same floor plate, because the thicker pour changes formwork, curing time and pump access. Bill them as one line and your rate averages out wrong for both.
MEP builderswork
This is where most disputes start. NRM2 draws a boundary between the builderswork, chasing, penetrations, fire-stopping around services, and the M&E installation itself. Get that boundary vague in the description and the M&E subcontractor and the main contractor end up arguing over who priced what, usually after the work is already done.
Where NRM2 bills go wrong
Three patterns cause most of the trouble we see on bills that come to us for review.
Vague descriptions. NRM2 gives the framework, but the wording inside each item still has to specify location and context, not just quantity. "Formwork to soffit" tells nobody anything useful. "Formwork to soffit, suspended slab, level 2, 300mm thick" does.
Provisional sums treated like provisional quantities. These are not the same thing, and mixing them up is one of the most common NRM2 errors we see. A provisional sum covers work that can't be defined yet at all. A provisional quantity covers work that's defined but not yet fully measurable. Bill one as the other and your risk allowance sits in the wrong place.
Interface gaps between trades. Groundworks stops, drainage starts, who bills the connection detail? These interface points are where scope quietly disappears from a bill, and where contractors discover mid-project that nobody actually priced the joint.
A cheap-looking BoQ built on thin descriptions isn't a cheap project. It's a project with the risk hidden instead of priced.
NRM2 inside a real estimating workflow
NRM2 on its own is a rulebook. What matters is how it sits inside the actual job of pricing a project. We start with a measurement strategy before take-off begins, aligned to the procurement route and how developed the drawings are. From there, quantities get taken off to NRM2 Part 3 rules, section by section, and priced against current UK material and labour rates. The bill then reconciles back against the NRM1 cost plan where one exists, giving a genuine check rather than two documents that were never compared.
Tender analysis is where NRM2 earns its keep. A consistent bill lets you compare two contractor tenders on the same basis and spot a genuine commercial difference instead of a scope misunderstanding dressed up as a lower price. That's the whole point of the standard: not paperwork for its own sake, a shared basis everyone can actually price against.
Blaze Estimating measures every project to NRM2, following UK construction standards and guidelines, across residential, commercial and trade work UK-wide. 9+ estimators, 10-48 hour turnaround, 95% accuracy rate on 6,000+ completed projects.
Frequently asked questions
A bill built on vague descriptions costs you at tender, not before.
Send us your drawings. We'll measure to NRM2 with descriptions tight enough to tender on, in 10-48 hours.
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