NEWScaffEngine — the 3D builder. Model the scaffold before anyone leaves the yard
ScaffoldOptixScaffolding software
Cards & Competence5 May 2026 · 4 min read · Updated 27 September 2026

Subcontract labour: what evidence do you hold?

Using subcontract labour is normal and often unavoidable when work comes in faster than a squad can grow. What varies enormously between firms is what they actually hold about the individuals who turn up — and the gap between a contractual assurance and evidence about a named person is where the exposure sits.

The client sees one contractor

From the client's perspective the people on their site are yours, whoever pays them. If an operative's competence is questioned, the client asks you, and a clause in a supplier agreement is a poor answer to a question about a specific person on a specific day.

Hold it before the shift, not after

The workable arrangement is holding the same evidence for subcontract operatives as for your own, obtained before they start. That is more administration and it is the only version that survives being asked about someone who worked six months ago — which is when it usually gets asked.

It also has to reach the people making decisions. Evidence held in an office does not help whoever is building gangs at seven in the morning and deciding who goes on which structure.

Suppliers change, and assurances age

An assurance obtained when a supplier was engaged describes that supplier as it was. Suppliers lose the staff who understood the requirement, change their own processes, and take on their own subcontractors. Re-checking the arrangement occasionally is unglamorous and catches all three.

Common mistakes

  • Relying on a contractual assurance rather than evidence for the individual
  • Obtaining evidence after the operative has already worked
  • No record of which subcontract operatives worked which structures
  • Evidence held centrally but not visible where allocation happens
  • Never re-checking a supplier's arrangements after initial engagement
  • Applying a lower evidential standard than to your own operatives

In practice: asked about somebody who left months ago

A client queried the competence of an operative who had worked two weeks on their site the previous spring through a labour supplier. The contractor had no record of which individual it had been, because the supplier's people were logged by squad rather than by name.

The operative was almost certainly appropriately carded. The point is that the contractor could not demonstrate it, six months later, about a named person — and that is the form the question always takes.

Log the individual, not the supplier

The record that matters is which named person worked which structure on which dates, with their evidence attached. Logging a supplier and a headcount is operationally sufficient and evidentially useless.

It is also what allows a contractor to respond quickly rather than going back to the supplier and hoping their records are better — which, when the query concerns something months old, they frequently are not.

Worth knowing: agree the evidence standard in the contract

The time to establish what a labour supplier will provide, and when, is when the arrangement is set up — not the first time you need something for an individual. A supply agreement that specifies exactly what evidence arrives before an operative attends removes the argument entirely.

  • Specify the evidence standard in the supply agreement
  • Require it before attendance, not on request
  • Audit a sample occasionally rather than assuming compliance

One more thing: the same standard, or the gap is yours

Where a firm applies a lower evidential standard to subcontract labour than to its own, the difference is invisible in good times and entirely visible in an audit. The practical test is whether you could produce, for a subcontract operative who worked last month, the same file you could produce for an employee.

  • Hold the same evidence for subcontract labour as for employees
  • Obtain it before attendance rather than on request
  • Audit a sample of supplier-provided evidence occasionally

Where this connects: agree the standard in the supply agreement

The time to establish what evidence arrives, and when, is when the supply arrangement is set up — not at seven on the morning somebody is needed. An agreement specifying exactly what is provided before an operative attends removes the awkward conversation entirely, because it has already been had once, calmly.

It is also worth auditing occasionally rather than assuming. Suppliers change their own processes and lose the people who understood the requirement, so an assurance obtained two years ago describes an organisation that may no longer work that way — and the question, when it comes, will be about a named individual on a named date.

  • Specify the evidence standard in the supply agreement
  • Require it before attendance rather than on request
  • Log which named individual worked which structure, and when
  • Audit a sample of supplier evidence periodically
  • Apply the same standard as to your own operatives
  • Make the evidence visible where allocation happens

Key takeaways

  • The client sees one contractor on their site, and it is you.
  • Hold the same evidence for subcontract labour as for your own people.
  • Obtain it before the first shift, not after a question is asked.
  • Record which subcontract operatives worked which structures, and when.
  • Re-check supplier arrangements periodically — assurances age.

The ScaffoldOptix team

Written by people who work daily with principal contractors on CDM design, inspection and the records that hold up when a client asks.