Common Assessment Standard renewal: what evidence should change?

Build UK says companies are certified once a year against the Common Assessment Standard (CAS) by a recognised assessment body. Renewal is not simply paying a fee or uploading last year's folder. The assessor needs the current question set and evidence that still describes the organisation, its people, work and arrangements.

This guide is for a supplier that already holds CAS certification and is preparing for its next assessment. It does not specify a provider's fee, deadline or guaranteed renewal outcome. Those are controlled by the chosen assessment body's current terms. For a first application or overview of CAS levels, see the CAS explainer.

Start with what changed in the business

Compare the current and previous assessment records. Has the legal entity, trading name, ownership, turnover, employer status, main trade, subcontracting pattern, design role or site activity changed? Has the company begun work on different building types or taken on a principal-contractor role? These facts can change which questions apply and which supporting files are relevant.

Record each change with an owner and date. Do not assume that a policy belonging to a predecessor entity or a group company covers the current applicant. If the change affects certification scope, ask the recognised assessment body what evidence it requires before the renewal submission.

Use the current question set, not last year's answers

Build UK reviews CAS and publishes the current question set. At the time of this review, its CAS page identifies Version 5 and announces Version 6 for 1 November 2026. A supplier renewing after a version change should compare every affected question, exemption and evidence instruction with the version the assessor will use.

Create a change log with: old question number, current question number, what changed, evidence owner, response update and reviewer. Do not reuse a previous N/A without checking whether the underlying fact still holds. Build UK's July 2026 Building Safety transition statement is an example of why this matters: until Version 6 is published, all renewing suppliers are to complete competence questions 135, 136 and 138 even if other dutyholder questions are not applicable.

Refresh time-sensitive evidence

Check the underlying document, not only a spreadsheet expiry date. The current CAS financial questions ask for accounts and insurance information, including entity name, policy number, limit and expiry. Check that the documents cover the current period and actual applicant. If a policy renews just before or after the CAS assessment, coordinate with the broker and assessor so the accepted file matches the live cover.

Also review training and competence records, policy approval dates, incident and improvement records, subcontractor arrangements, environmental evidence and any role-specific site examples that the current question set requests. A policy may be formally in date but no longer reflect the company's method. An auditor or buyer may reasonably ask how an arrangement operated in practice.

Build UK's data-sharing overview says certain verified answers and time-critical information can appear in other recognised bodies' portals, but underlying certificates and documents are not shared through that mechanism. After renewal, confirm the originating body's record is current and check visibility in the portals on which your buyers rely. The sharing guide explains the separate consent process.

Close assessor questions with a decision record

Keep each assessor query, the original answer, requested clarification, source document, response date, reviewer and final accepted version together. If a question cannot be answered honestly, do not invent an example or present a draft policy as operating practice. Resolve the underlying gap or ask the assessor how to record it.

Renewal is also a useful point to separate CAS certification from the buyer's work-specific checks. A renewed certificate does not prove the named team, equipment, insurance scope or RAMS is suitable for every new site. The initial insurance check and prequalification-to-mobilisation handover deal with those separate decisions.

Maintain a renewal register

Use a short register with the recognised assessment body, product and level, current certificate reference, assessment date, next renewal date, question-set version, evidence owners, time-critical file dates and unresolved assessor queries. Assign a person to recheck it when the business changes; an annual diary reminder alone is not enough.

If evaluating contractor prequalification software, ask whether it can show the evidence owner, document version, exception and renewal decision. Require a demonstration of the precise workflow. Complys does not renew CAS certification, validate a recognised body's assessment or guarantee acceptance by a buyer.

Primary sources and publication gate

• Build UK — Common Assessment Standard: annual certification, current recognised bodies and announced version transition.
• Build UK — Version 5 question set: current evidence and conditional answers, including accounts and insurance.
• Build UK — Data Sharing: An Overview: shared answers, time-critical information and the absence of underlying document transfer.
• Build UK — Building Safety transition statement: temporary mandatory competence questions until V6.

Before publication: Recheck Build UK's current question-set version, every provider-specific deadline and the whole live CAS overview. If the overview now serves the annual renewal task fully, merge these steps into that owner instead of creating another generic CAS result.