TWS vs TWC: Roles, Responsibilities, and Who Signs Off What

If you've worked on a UK construction site with any temporary works — scaffolding, excavations, formwork, propping — you've likely come across the terms TWS and TWC. They sound similar, and their responsibilities overlap, but under BS 5975 they're distinct roles with different sign-off authority.

Temporary Works Coordinator (TWC)

The TWC sits at project level and is ultimately responsible for how temporary works are managed across the whole site. Core responsibilities:

• Maintaining the temporary works register
• Ensuring every item has an appropriate design and design check
• Confirming permits to load/use are issued before work proceeds
• Acting as the main point of contact for temporary works queries
• Reporting to the principal contractor on temporary works status

Temporary Works Supervisor (TWS)

The TWS operates at the coalface — on the specific temporary works item itself. Core responsibilities:

• Supervising installation, use, and dismantling on site
• Carrying out and recording inspections
• Checking work matches the design and method statement
• Reporting any deviation, damage, or defect to the TWC immediately
• Confirming components are struck safely once no longer required

Where the Overlap (and Confusion) Comes From

On smaller projects, the same person is sometimes both TWC and TWS — which is permitted, but blurs the line on independent checking. On larger or higher-risk projects, BS 5975 expects clear separation, so that design assurance (TWC) and site-level supervision (TWS) are genuinely independent of each other.

Quick Reference

Why This Matters for Compliance

Auditors and HSE inspectors will often ask directly: "who is your TWC?" and "who signed off this permit to load?" If the answer isn't immediate and the paper trail isn't clear, that's a red flag — regardless of whether the physical works are safe.

Making Sign-Off Traceable

Digital platforms like KaelSite assign these roles directly to team members, so every inspection, permit, and register entry is tied to the person who actually signed off on it — making the TWS/TWC split provable, not just theoretical.