Subcontractor prequalification checker
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Fourteen things to check before you appoint a subcontractor, graded must / should / nice, with a verdict on whether they are ready to approve.
Why you have to check
CDM 2015 regulation 8 says anyone appointing a designer or contractor must take reasonable steps to satisfy themselves that the appointee has the skills, knowledge, experience and, for an organisation, the organisational capability to do the work safely. If your subcontractor's labourer is injured and the subcontractor had no insurance, no RAMS and no cards, the question comes to you: what did you check? This checklist is the answer, and the fourteen items are the ones principal contractors and SSIP schemes ask for.
Proportionate, not paperwork for its own sake
A one-man ground worker does not need ISO 9001. He does need employers' liability if he ever brings a mate, public liability, a RAMS for the job and a card that says he can drive the machine. The must / should / nice grading keeps the check proportionate: the must-haves are non-negotiable, the should-haves are asked for and the gaps recorded, the nice-to-haves depend on the contract. The subcontractor prequalification guide covers what to do when a good subcontractor fails a should-have.
FAQs
What insurance must a subcontractor have?
Employers' liability insurance of at least £5 million is a legal requirement for almost every employer under the Employers' Liability (Compulsory Insurance) Act 1969. Public liability is not a legal requirement but is a standard contractual one; the level depends on the contract, commonly £2m to £10m.
Does a subcontractor need a written health and safety policy?
Employers with five or more employees must have a written health and safety policy under HSWA section 2(3). Smaller subcontractors are not legally required to write one down, but most principal contractors ask for one regardless.
Is an SSIP certificate compulsory?
No. SSIP schemes such as CHAS and Constructionline are voluntary assessments that many clients and principal contractors require contractually. A subcontractor without one can still demonstrate competence with the underlying documents.
How often should I re-check a subcontractor?
Insurance certificates expire annually, so at least yearly, and whenever the work changes to something outside what you originally assessed.
Get the documents ready-made
The checklist is the assessment. The onboarding pack is everything around it - the questionnaire you send them, the approved subcontractor register, the induction record and the review form.
Prequalification questionnaire, approved contractor register, insurance tracker, induction record and performance review, all editable Word.
See the Subcontractor PackBuilt by Pro Site Docs from the HSE guidance and regulations named on the page. Published 3 September 2026. It is a planning aid, not a substitute for a competent person's assessment of the actual work.
Keep reading
General guidance only. This article explains how the rules generally work in UK construction. It is not advice for your specific site, task or project, and it is not legal advice. Your own risk assessment, method statement and arrangements must be prepared and checked by a competent person for the actual work being done.