Under RICS NRM2, preliminaries (Work Section 1) cover the non-building items needed to set up, manage and secure a site rather than the works themselves. NRM2 splits this section into information and requirements and a pricing schedule, separating what the employer must state from what the contractor must price. The single most important action for any QS drafting a bill: include an NRM2-style pricing schedule and insist that the main contractor submits a full, itemised breakdown with their tender.
TL;DR:
- Preliminaries in NRM2 are structured into information and requirements and a pricing schedule to ensure accurate, non-measured site establishment costs.
- Contractors should provide a detailed breakdown of their preliminaries costs, supported by method statements, to prevent disputes and enable fair interim valuations.
- Benchmark percentages from BCIS are starting points and should be rebased for project location, size, and scope, especially in constrained or complex sites where costs can significantly exceed typical figures.
- Statutory duties under CDM 2015, such as welfare facilities and site management, are integral to preliminaries and should be cross-referenced with contractor method statements early in the process.
- Using tools like Quantiflow can assist in drafting preliminary schedules, but QSs must verify and adapt the generated data to ensure alignment with project-specific site and contract conditions.
Table of Contents
- What does NRM2 say about preliminaries?
- What items belong in a preliminaries bill?
- Drafting the pricing schedule and tender instructions
- Using BCIS benchmarks without misreading them
- CDM 2015 and site establishment: costing statutory duties
- A checklist to reduce valuation disputes
- Where a drawing-reading tool fits into the preliminaries workflow
- Sources
- FAQ
What does NRM2 say about preliminaries?
RICS designed Work Section 1 of NRM 2: Detailed measurement for building works to give quantity surveyors a consistent way to capture the management, establishment and running costs of a site, separate from the measured works. That consistency matters because preliminaries rarely behave like other bill items. You cannot measure a metre of scaffolding the way you measure a metre of brickwork, so NRM2 gives you a structure instead of a tape measure.
The structure has two parts. Information and requirements sets out what the contractor needs to know to price sensibly: project particulars, drawings, contract conditions, access constraints, phasing, and any employer stipulations that shape site logistics. The pricing schedule is where the contractor inserts their own costs against a defined list of cost centres, split between employer's requirements and the contractor's own management and site-running costs. NRM2 provides these as ready-made templates in Appendices B and C, covering condensed and expanded formats depending on project complexity.
This is where many QSs go wrong early in their careers: trying to quantify the main contractor's preliminaries as if they were measurable items. You cannot reliably predict how many site managers a contractor will deploy, how they will sequence their welfare cabins, or what plant hire strategy suits their programme. NRM2 recognises this. Instead of demanding false precision, it asks the QS to:
- Provide clear, complete information so contractors can price their own methodology accurately
- Issue a structured pricing schedule that captures every relevant cost centre
- Require a detailed contractor breakdown to support the lump sum entered against each item
Get the structure right, and you shift the burden of proof onto the contractor, exactly where it belongs.
What items belong in a preliminaries bill?
A well-drafted preliminaries section reads like two separate lists stitched together: what the employer is responsible for, and what the contractor must price to run the site.
Employer's requirements typically include:
- Site boundary definition, access restrictions and shared-use arrangements
- Client accommodation or facilities the contractor must provide during the works
- Programme constraints, including phased handovers or restricted working hours
- Operation and maintenance manual requirements and as-built documentation
- Completion and defects-liability period obligations
Main contractor cost items typically include management and supervisory staff, site accommodation and welfare facilities, temporary services (power, water, telecoms), common-user plant such as tower cranes or hoists, temporary works design and installation, site security, cleaning and waste management, and insurance and performance bonds.
Where the project uses work packages rather than a single main contract, keep package-specific preliminaries separate from main-contract preliminaries. NRM2's tabulated rules give you the codification to do this cleanly, so a groundworks package and an M&E package each carry their own site-running costs without double-counting shared items like the main contractor's welfare block.
Pro Tip: Build your preliminaries checklist directly from the NRM2 Appendix B template rather than a generic in-house list. It already separates employer and contractor cost centres in the order tender assessors expect, which speeds up comparison across multiple returns.
Drafting the pricing schedule and tender instructions
A pricing schedule only works if the information behind it is complete enough for contractors to price with confidence. Before you issue anything, make sure the tender pack states the programme duration and key milestones, site access and storage constraints, phasing or partial possession requirements, and any retained operations nearby that will affect logistics. Contractors price conservatively when information is vague, and vague pricing is where disputes start.
NRM2 offers both condensed and expanded pricing schedule templates in its appendices. Use the condensed version for straightforward, single-phase projects, and switch to the expanded version once you are dealing with multiple phases, several contractors on site, or complex temporary works. Whichever you choose, NRM2's own guidance is explicit that the contractor should append a full, detailed breakdown showing how the lump sum for each preliminaries item has been calculated, submitted alongside the priced bill of quantities.
Your tender documents should:
- State that a detailed preliminaries breakdown is a condition of a compliant tender, not an optional extra
- Set out how preliminaries will be apportioned and assessed during interim valuations
- Require method statements for any significant temporary works, so pricing and safety planning align from day one
At tender opening, check completeness before you check numbers. A breakdown missing staff resourcing, plant duration, or temporary works allowances is incomplete regardless of how competitive the headline figure looks. Raise gaps as tender clarifications rather than accepting a lump sum on faith.
Using BCIS benchmarks without misreading them
Historical percentages are a starting point, never a verdict. BCIS guidance on project preliminaries treats the pricing schedule as a list of cost centres rather than a prescriptive cost table, and recommends rebasing any benchmark figure to the specific location, date and contract value of your project before relying on it.
The scale of variance is the reason rebasing matters so much. A BCIS featured analysis of a nursery extension recorded preliminaries at 46.33% of the contract sum, driven almost entirely by site restrictions that would not apply to a typical greenfield scheme. Treat that figure as an illustration of extremes, not a benchmark to copy.
Common drivers that push preliminaries above a standard benchmark:
- Restricted or shared site access
- Retained operations continuing alongside the works
- Number of storeys and vertical logistics complexity
- Extent and complexity of temporary works
- Phasing of M&E installation and commissioning
A sound workflow starts with a benchmark percentage from BCIS or a comparable in-house dataset, lists which of these drivers apply and by how much, and records the rationale directly in the preliminaries bill so the reasoning survives into the final account.
CDM 2015 and site establishment: costing statutory duties
Preliminaries are not purely a costing exercise. Under CDM 2015, the principal contractor must plan, manage, monitor and coordinate the construction phase and produce a written Construction Phase Plan. Many preliminaries line items exist specifically to discharge those duties: welfare facilities, temporary works permits, site inductions, and the records that prove compliance.
Before finalising a preliminaries bill, check the pre-start information pack includes:
- A draft Construction Phase Plan covering welfare, emergency arrangements and site rules
- Temporary works registers and design check procedures
- Site record-keeping arrangements, including induction and permit-to-work logs
Pro Tip: Cross-reference each preliminaries line item against the relevant CPP section and ask the contractor to confirm alignment at tender stage. It catches gaps before they become disputes during the works, not after.
A checklist to reduce valuation disputes
Most preliminaries disputes trace back to a gap that existed from day one, not a disagreement that emerged mid-project. Close the obvious gaps and most of the argument disappears with them.
At pre-tender stage, confirm drawings, site logistics information and pre-start data are complete before issuing documents. At tender stage, insist on a detailed breakdown and scrutinise plant allowances, management staffing levels and temporary works costs line by line, not as a single lump figure.
- During interim valuations, agree the apportionment method up front and update it whenever the programme or methodology changes materially
- At final account, require the supporting breakdown to be attached and reconciled against actual site records, not just the original tender submission
Pro Tip: Keep a running log of any agreed changes to preliminaries assumptions during the contract. It turns final account reconciliation into an administrative check rather than a renegotiation.
Where a drawing-reading tool fits into the preliminaries workflow
Assembling a preliminaries pricing schedule still means cross-referencing drawings, contract particulars and site constraints by hand for most QS teams. Quantiflow reads construction drawings and produces a draft bill of quantities for a quantity surveyor to review and sign off, which can extend to a draft preliminaries pricing schedule alongside an audit trail of how quantities were derived.
Quantiflow is in development, and its role is to give you a starting draft, not a finished answer. You still verify every line, apply your own judgement on cost centres, and require the contractor breakdown NRM2 asks for regardless of which tool assembled the first draft. Plans run from Solo to Business to Enterprise, detailed at Quantiflow.
Sources
For deeper reference, read the NRM2 explained overview, the BCIS benchmarking guide, and RICS's own NRM2 appendices.
- BCIS basics: understanding project preliminaries
- Principal contractors: Construction (Design and Management) Regulations 2015 (HSE)
FAQ
How do you calculate preliminaries?
You do not calculate the main contractor's preliminaries directly. NRM2 asks the QS to issue a pricing schedule of cost centres and require the contractor to submit their own priced, detailed breakdown against each one, which the QS then checks for completeness rather than recalculating from scratch.
What are the NRM2 standards?
NRM2, published by RICS, is the standard method of detailed measurement for building works in the UK. It sets consistent rules for measuring the works and for structuring preliminaries into information and requirements plus a pricing schedule, so bills of quantities from different projects remain comparable.
What is the typical percentage of construction preliminaries in the UK?
There is no single fixed percentage, since preliminaries respond heavily to site constraints, and comparing projects without rebasing gives a misleading picture. BCIS recommends using historical data only as a rebased starting point; on a highly restricted nursery extension, BCIS recorded preliminaries at 46.33% of the contract sum, well above what a standard scheme would show.
Who are tier 2 contractors in the UK?
Tier 2 contractors are typically specialist subcontractors or works package contractors engaged by a main (tier 1) contractor to deliver a defined scope, such as groundworks, steelwork or M&E installation. In an NRM2 bill, their preliminaries should be kept distinct from main-contract preliminaries to avoid double-counting shared site facilities.
Recommended
- NRM2 explained: the RICS standard for measuring building works
- Stop Final Account Disputes: NRM2 Prime Cost Sums for UK QSs
- Keep Tender Quantities Within ±5%: NRM2 Workflow for UK QS
- Construction measurement quality control: the UK SME guide
This article is for general information only and is not professional, legal or commercial advice. Quantity surveying decisions should be taken by a qualified professional with reference to the specific project, drawings and contract in question. Content is produced with AI assistance and reviewed before publication. QuantiFlow Ltd accepts no liability for reliance on it.