Duty holders & appointments
What is a contractor?
A contractor under CDM is anyone who carries out or manages construction work. Every contractor has duties, whether or not there is a principal contractor above them.
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<figure>
<img src="https://buildoptix.co.uk/glossary/contractor/diagram.svg" alt="contractor — diagram from BuildOptix" width="880" height="620" loading="lazy">
<figcaption>
<a href="https://buildoptix.co.uk/glossary/contractor">What is a contractor?</a> — diagram by
<a href="https://buildoptix.co.uk">BuildOptix</a>
</figcaption>
</figure>On a single-contractor project the contractor takes on duties that would otherwise sit with a principal contractor, including producing a construction phase plan.
Where there is a principal contractor, contractors must coordinate with them, follow site rules, and not start work until they have the information and arrangements they need.
Sub-contractors are contractors too, all the way down the chain, which is why a labour-only firm several tiers down still carries duties of its own rather than inheriting somebody else's.
What goes wrong in practice
- Single-contractor projects run with no construction phase plan at all.
- Sub-contractors assuming the principal contractor's arrangements discharge their duties.
- Work started before the information needed to plan it was obtained.