Moving From NEC3 to NEC4

Moving from NEC3 to NEC4 is mostly a job of updating templates, registers and habits, as the underlying method hasn't changed. Treat it as a short project with a named owner. The risk isn't that people fail to understand NEC4, but that old letters and old assumptions quietly carry on.

This page gives a practical list for ECC teams. To see what changed, read NEC3 vs NEC4, and for the overview, see the NEC4 contracts guide.

First decide what is moving

A live NEC3 contract doesn't become NEC4 because a new edition exists. Both editions will probably run side by side in your business for years.

Situation	What usually happens
New contract on NEC4	Use the NEC4 pack from the start
Live NEC3 contract	Carries on under NEC3
Live contract that the Parties want to change	Needs an agreed variation, drafted with legal advice, covering how open matters are treated
A framework call-off	Follows the form the framework specifies, so check it
NEC4 main contract, NEC3 subcontract	Possible, but the two won't line up. Move the subcontract to the ECS if you can

Change checklist

Templates and letters

• Change words: Client, Scope, Early Warning Register, early warning meeting. See NEC4 terminology changes.
• Check every clause reference. Early warnings, Defects, implementation and proposed instructions have all moved.
• Add new letters: a failure to reply to a programme (31.3), a Contractor's proposal (16.1) and a Contractor's final assessment (53.2).
• Keep the old NEC3 pack, and label both clearly so nobody picks up the wrong one.

Registers and diaries

• Rename the register, and add an action review column for 15.3.
• Add dates: first register, first meeting, revised register within a week of each meeting.
• Add the programme treated-acceptance countdown.
• Add the final assessment, and the time limit to refer a dispute about it.

Payment and cost

• Make the application for payment a monthly deadline (50.2), and put it in the form the Scope states.
• Change tender models to a single fee percentage.
• Remove NEC3 overhead percentages from quotation templates.
• On Options A and B, set up People Rates. See cost and Fee changes.
• On Options C, D and E, plan which parts of cost to finalise under 50.9.

Documents you issue or tender

• Use the NEC4 Contract Data form instead of adapting an old one. See NEC4 Contract Data explained.
• State the form of programmes and applications in the Scope, because NEC4 relies on the Scope for these.
• Add the quality management requirements that clause 40 refers to.
• Decide on the new Options: X10, X11, X21, X22 and W3.
• Name your Senior Representatives.
• If the Scope names a contract management system, remember that clause 13.2 links the date of communication to it.

Z clauses

• Review each one individually. Some NEC3 Z clauses are no longer needed, since NEC4 may now do the same job.
• Correct cross-references. A Z clause amending "clause 16" means something different now.
• Don't convert them with a simple search and replace.

Subcontracts

• Use the NEC4 ECS with NEC4 main contracts where you can.
• Line up periods. In the standard ECS, 61.3 is 7 weeks and quotations are due in 2 weeks, so the timing works with the main contract.
• Consider your exposure if a subcontract is on a different edition. See back-to-back subcontracts.

People

• Run a short session on the differences. Learning NEC4 sets out what each role needs.
• Tell people which edition each job is on. A simple label on the project page helps.
• Review the first few notices on the first NEC4 job.

A simple plan

When	What	Who
Tender stage on the first NEC4 job	Pricing model, Contract Data review, Z clause review	Commercial lead, bid team
Before the starting date	Template pack, register, diary dates, training session	Contract administrator
Starting date plus 2 weeks	First register and first meeting done; check the first notices	Project Manager, Contractor's lead
After the first assessment	Review the application and certificate process	Quantity surveyor
After three months	Lessons learned; correct the template pack	Owner of the change

What people get wrong

• Converting the pack and stopping there. Diaries and habits are where the real change happens.
• Assuming the first programme is the only issue on day one. In NEC4 the register and first meeting fall due very early as well.
• Using one set of templates for both editions. It looks efficient, but it's how the wrong clause numbers get into notices.

Related guides

• NEC4 Contracts: A Complete Guide
• The NEC3 Risk Register
• NEC3 Risk Reduction Meetings
• Works Information vs Scope
• NEC3 Contracts Explained
• NEC3 Main Options

This guide is general information in our own words, not legal advice. Your contract and its Contract Data always govern. NEC, NEC3 and NEC4 are trade marks of Thomas Telford Ltd; Contract Status is not affiliated with or endorsed by NEC.