Commencement of construction works
In very broad terms, the word ‘commencement’ means beginning something. In the construction industry this generally refers to the contractor beginning the construction works, ie the point at which site clearance, demolition, excavation or construction begins. For more information see: Construction operations definition.
Commencement of construction works will be proceeded by activities such as design, procurement and mobilisation, and there may be legal requirements that need to be satisfied, such as obtaining planning permission, satisfying planning conditions or planning obligations, obtaining building regulations approval, obtaining a party wall agreement, notifying the Health and Safety Executive and so on. For more information see: What approvals are needed before construction begins.
In addition, commencement may be required before a certain point, for example, within 3 years of the date planning permission was granted, or within three years from the date of deposit of plans for building regulations approval.
Commencement may also have contractual implications, as the date for possession of the site by the contractor may be set out in the contract. If the client fails to give possession of the site to the contractor, and there are no provisions for delay in the contract, then they will be in breach of contract. Even if the contract does provide for delay in giving possession of the site to the contractor, the contractor may still be able to claim for an extension of time and perhaps loss and expense.
If no date for possession is included in the contract, then the site must be handed over to the contractor within a reasonable time after signing of the contract.
On commencement of the works, the contractor may become responsible for insurance, security of the site and so on, and may be obliged to progress regularly and diligently with the works, or to achieve certain key dates.
The term ‘commencement’ might also be used to refer to the commencement of an appointment, the commencement of a contract, commencement of legal proceedings and so on.
NB There is currently no legal UK definition of (as opposed to guidance on) "commencement" for the purposes of the building regulations. Knowing whether work has commenced will be critical to understanding whether approval has lapsed and/or whether work benefits from transitional provisions. Consequently, a legal definition of "commencement" is being considered.
[edit] Related articles on Designing Buildings
Featured articles and news
CIOB Apprentice of the Year 2025/26
Construction apprentice from Lincoln Mia Owen wins this years title.
Insulation solutions with less waste for a circular economy
Rob Firman, Technical and Specification Manager, Polyfoam XPS explains.
Recycled waste plastic in construction
Hierarchy, prevention to disposal, plastic types and approaches.
UK Net Zero Carbon Buildings Standard V1 published
Free-to-access technical standard to enable robust proof of a decarbonising built environment.
Prostate Cancer Awareness Month
Why talking about prostate cancer matters in construction.
The Architectural Technology podcast: Where it's AT
Catch up for free, subscribe and share with your network.
The Association of Consultant Architects recap
A reintroduction and recap of ACA President; Patrick Inglis' Autumn update.
The Home Energy Model and its wrappers
From SAP to HEM, EPC for MEES and FHS assessment wrappers.
Future Homes Standard Essentials launched
Future Homes Hub launches new campaign to help sector prepare for the implementation of new building standards.
Building Safety recap February, 2026
Our regular run-down of key building safety related events of the month.
Planning reform: draft NPPF and industry responses.
Last chance to comment on proposed changes to the NPPF.
A Regency palace of colour and sensation. Book review.
Delayed, derailed and devalued
How the UK’s planning crisis is undermining British manufacturing.
How much does it cost to build a house?
A brief run down of key considerations from a London based practice.
The need for a National construction careers campaign
Highlighted by CIOB to cut unemployment, reduce skills gap and deliver on housing and infrastructure ambitions.






















Comments
[edit] To make a comment about this article, or to suggest changes, click 'Add a comment' above. Separate your comments from any existing comments by inserting a horizontal line.