NEC Option B: Priced contract with bill of quantities
NEC was first published in 1993 as the New Engineering Contract. It is a suite of construction contracts intended to promote partnering and collaboration between the contractor and client.
The Engineering and Construction Contract (ECC) is the most frequently used, and can be adopted on projects such as infrastructure, buildings, highways and process plants. It is used for the appointment of a contractor for engineering and construction work, including any level of design responsibility.
Under Option B, the bill of quantities is a ‘traditional’ bill of quantities, i.e. a document prepared by the cost consultant (often a quantity surveyor) that provides project specific measured quantities of the items of work identified by the drawings and specifications in the tender documentation.
From the employer’s specified quantities the contractor prices its rates accordingly, and bears the risk of carrying out the work at the agreed prices.
The contractor is entitled to interim payments, certified at assessment dates by the project manager as set out in the contract. The price for the work done to date is the quantity of completed work for each BoQ item multiplied by the relevant rate and a proportion of any lump sum item in the BoQ. The proportion of the lump sum items to be paid is determined by the extent to which they have been completed.
The contract contains core and secondary option clauses, the shorter schedule of cost components, and contract data.
[edit] Related articles on Designing Buildings
- Bill of quantities.
- Conditions of contract.
- Construction contract.
- Contract documents.
- Contractor's working schedule.
- NEC Option A: Priced contract with activity schedule.
- NEC Option C: Target contract with activity schedule.
- NEC Option D: Target contract with bill of quantities.
- NEC Option E: Cost reimbursable contract.
- NEC Option F: Management contract.
- NEC3.
- Right to payment.
- Term contract.
Featured articles and news
Costs and insolvencies mount for SMEs, despite growth
Construction sector under insolvency and wage bill pressure in part linked to National Insurance, says report.
The place for vitrified clay pipes in modern infrastructure
Why vitrified clay pipes are reclaiming their role in built projects.
Research by construction PR consultancy LMC published.
Roles and responsibilities of domestic clients
ACA Safety in Construction guide for domestic clients.
Fire door compliance in UK commercial buildings
Architect and manufacturer gives their low down.
Plumbing and heating for sustainability in new properties
Technical Engineer runs through changes in regulations, innovations in materials, and product systems.
Awareness of the Carbon Border Adjustment Mechanism
What CBAM is and what to do about it.
The new towns and strategic environmental assessments
12 locations of the New Towns Taskforce reduced to 7 within the new towns draft programme and open consultation.
Buildings that changed the future of architecture. Book review.
The Sustainability Pathfinder© Handbook
Built environment agency launches free Pathfinder© tool to help businesses progress sustainability strategies.
Government outcome to the late payment consultation, ECA reacts.
IHBC 2025 Gus Astley Student Award winners
Work on the role of hewing in UK historic conservation a win for Jack Parker of Oxford Brookes University.
Future Homes Building Standards and plug-in solar
Parts F and L amendments, the availability of solar panels and industry responses.
How later living housing can help solve the housing crisis
Unlocking homes, unlocking lives.
Preparing safety case reports for HRBs under the BSA
A new practical guide to preparing structural inputs for safety cases and safety case reports published by IStructE.
Male construction workers and prostate cancer
CIOB and Prostate Cancer UK encourage awareness of prostate cancer risks, and what to do about it.






















Comments