A clerk of works inspects the execution of the building work on behalf of the client or the architect. They check that the work is being built to the specification, drawings, consents and applicable regulations, and pick up deviations before they disappear into the finished building.
The architect cannot be on site every day. Anyone who wants to safeguard quality therefore appoints someone who can. The clerk of works acts for the client or the architect — emphatically not for the contractor.
What the role involves
- Regular or daily inspection on site, recorded in a site diary or weekly report.
- Checking setting out, materials and workmanship — is the specified brick arriving at the facade, is the reinforcement where the drawing says, is the insulation the right thickness.
- Protecting the inspection moments. Some things can only be checked before they are closed up: reinforcement before the pour, services before boarding out, the vapour control layer before the plasterboard.
- Assessing variations and advising the client on them.
- Recording defects at handover and following the snagging list through to completion.
Inspect before it is closed up
- Reinforcement: Check before the pour.
- Services: Check before boarding out.
- Vapour control layer: Check before the plasterboard.
Confusion with three other roles
| Role | Works for | Does what |
|---|---|---|
| Clerk of works / site inspector | Client or architect | Safeguards quality, programme and contract for the client |
| Site manager / foreman | Contractor | Runs the site and the subcontractors for the builder |
| Building control | Local authority or approved inspector | Enforces the building regulations and the consent |
| Structural engineer | Client design team | Designs and checks the structure; may attend key inspections |
Important to understand: building control checks compliance with the regulations. It does not protect your contract, your finish standard or your budget. That is exactly what a clerk of works is for.
Worth it on a private project too
Even on a domestic extension or refurbishment, independent inspection pays:
- A pre-contract survey or second opinion on drawings and tender; expect an order of magnitude of a few hundred in local currency.
- A handful of targeted visits at the critical moments: foundations and reinforcement, structure closed in, insulation and airtightness, handover.
- Written into the contract that the client appoints an inspector and that they have access to the works.
Rule of thumb: the cheapest moments to correct something are on the drawing and before it is closed up. Any fault you only see at handover costs a multiple to put right.
Related terms
- Specification
- Main contractor
- Structural engineer
- Building regulations
- Planning permission
Learn more about building terms in our knowledge base at fredsdiyplans.com.