Build UK publishes version 6 of the Common Assessment Standard (CAS v6) on 1 November 2026. Competence questions 135, 136 and 138 move from the Building Safety section to the Quality section, so every supplier completes them. Scaffolding and temporary works suppliers also stop completing the Building Safety section unless they carry out building work.

CAS is Build UK’s industry-agreed question set and assessment standards for pre-qualifying construction suppliers, and a Recognised Assessment Body (one of seven organisations Build UK recognises) audits and certifies you against it. Any supplier certifying or renewing before 1 November already has to complete questions 135, 136 and 138, even where the rest of Building Safety doesn’t apply. Electrical, HVAC and plumbing and heating subcontractors will probably still complete Building Safety, so for them the change is mainly where those three questions sit, and the job is to get competence and supervision evidence ready before the next renewal.

What changes in Common Assessment Standard version 6?

Build UK’s statement of 23 July 2026 sets out the changes. After advice from Wedlake Bell LLP, supported by a letter from the Building Safety Minister, Build UK concluded that scaffolding and temporary works fall outside the Building Regulations rules on building work unless they form part of the finished structure. They still come within the Building Safety Act’s aim of raising competence across the industry, so the competence questions apply to every supplier.

Source: Build UK, Common Assessment Standard Building Safety Section statement

Constructionline moved questions 135, 136 and 138 to Quality on its platform on 15 September 2026, ahead of the official date. Other assessment bodies may handle the transition differently, so ask yours which version of the question set it will audit you against.

Build UK hasn’t published the version 6 question set yet, and its statement leaves three points open: how existing exemptions apply to the moved questions (a BS 99001 certificate exempts you from every Building Safety question under version 5), whether any question numbers change, and whether certificates already issued need re-auditing. Check the published question set on 1 November before you act on any other reported change.

Which subcontractors does version 6 affect?

Every supplier completes the three competence questions once they sit in Quality. Under version 5, you could skip them by answering no to question 22. Any supplier certifying or renewing now answers them anyway, so version 6 turns an interim rule into the standard position.

Electrical, HVAC and plumbing and heating subcontractors don’t fall under the scaffolding and temporary works change, and most will probably still complete Building Safety. Question 22 in version 5 asks whether you carry out building work regulated under the Building Regulations, and a yes means you complete the Building Safety section. If you install heating, hot water, ventilation, cooling or electrical systems in buildings, expect to answer yes and confirm it with your assessment body.

The reason is in the regulations. The Building Regulations 2010 define building work to include the provision or extension of a controlled service or fitting, which means a service or fitting covered by Parts G, H, J, L or P of Schedule 1: sanitation and hot water, drainage, combustion appliances, fuel and power, and electrical safety. GOV.UK’s dutyholders factsheet gives a boiler as an example of a controlled service. Question 22 in version 5 lists the provision or extension of controlled services or fittings among the work that triggers the Building Safety section.

If you’re a contracts or FM manager at a main contractor, the practical change is in the evidence you can ask for. Competence records and supervision arrangements for subcontractor roles now sit in Quality, so they apply to every subcontractor on your list. Build UK’s FAQs say shared CAS data updates in real time and shows where a company’s certification has lapsed because it hasn’t updated time-critical information such as insurances.

How do subcontractors prepare for Common Assessment Standard version 6?

Subcontractors prepare by checking their renewal date and gathering evidence for questions 135, 136 and 138. Build UK’s guidance lists examples of evidence rather than a fixed list, and version 6 may reword the questions, so treat the version 5 question set as a working checklist rather than final wording.

• Renewal date: note when your certificate expires and ask your assessment body which version of the question set it will use for your audit.
• Question 135, competence records: a process for identifying competence requirements, training records, certificates, CPD evidence and a competency matrix covering your workforce and key subcontractor roles.
• Question 136, supervision: how each team receives appropriate supervision, instruction and information. Build UK’s examples include a named supervisor for each team, a skills matrix showing the level of supervision for each activity, and a Quality Management Policy or statement that covers building work.
• Question 138, keeping up to date: a clear explanation of how you keep up with changes to relevant requirements, such as the Building Safety Act and the Building Regulations, including the Approved Documents.
• Your own subcontractors: questions 135 and 136 cover key subcontractor roles under your control, so be ready to show their competence and supervision as well as your own.
• Time-critical documents: check the expiry dates on your insurance certificates and your SSIP or ISO certificates now, because a lapse shows in shared CAS data.
• One owner: name one person who owns CAS evidence between audits.

Joblogic Compliance (powered by Clik) keeps your certificates and compliance documents in one searchable repository, so the certificates you hold are easy to produce when question 135 asks for competence records. It covers the certificates themselves. The training matrix, supervision arrangements and policies the questions also ask for still need to exist in your own documents.

How do you keep CAS evidence current between audits?

You keep CAS evidence current by updating time-critical documents when they expire and by being able to declare that no material breaches, legal or enforcement, have occurred since you were certified. A CAS certificate is valid for one year from the date of issue, provided those documents stay up to date. Build UK’s version 5 documents list marks all six insurance certificates, SSIP certificates and the ISO certificates as time-critical.

If you use subcontractors, these version 5 questions ask how you check and manage them:

• Question 38 (Financial): your checks that subcontractors are financially stable and have met their obligations to HM Revenue and Customs (HMRC).
• Question 116 (Environmental): evidence, such as an Environmental Management Policy, that you monitor subcontractors’ environmental procedures.
• Question 130 (Quality): a Sub-Contractor Selection Policy, approved by a director and reviewed within the last 12 months.
• Questions 135 and 136: competence records and supervision arrangements that cover key subcontractor roles. Both move to Quality in version 6.

If you employ no subcontractors, you skip questions 38, 116, 130, 139, 160, 165 and 166.

Joblogic Compliance (powered by Clik) is a cloud-based certification management system that centralises how you create, validate, store and share compliance documents. It sends automated alerts before certificates expire, so you can renew time-critical documents before shared CAS data shows a lapse. It’s built for field service businesses in regulated sectors such as electrical, HVAC and plumbing.

Joblogic’s subcontractor portal manages subcontractors in the same system you use for daily operations. You assign jobs, track performance and keep each subcontractor’s compliance documents on their record. Each document carries a type and an expiry date, and by default Joblogic emails the subcontractor’s compliance contact four weeks before, two weeks before and on the day of expiry, which gives you current paperwork to point to when questions 38, 130 and 135 come up at your next audit. Your subcontractors connect through their own Joblogic account, and Joblogic’s support team creates the link between the two accounts.

What is the Common Assessment Standard?

CAS is the industry-recognised standard for pre-qualifying companies in the construction sector, developed by Build UK. Pre-qualification is the check a buyer runs on a supplier before inviting it to bid. The standard pairs one question set with matching assessment standards, and a Recognised Assessment Body audits your answers and evidence before it certifies you.

Companies only need certifying once a year by a single Recognised Assessment Body, because they can share their key data with the others. Build UK’s FAQs, dated July 2025, say over 21,000 companies are certified. A growing list of contractors and clients accept CAS and no longer specify a particular assessment body. Build UK’s list includes Balfour Beatty, Kier, Skanska, Willmott Dixon and HS2, along with trade bodies such as BESA and FIS.

What does the CAS question set cover?

The version 5 question set, published on 1 July 2025, covers 10 sections. Most questions are mandatory, and failing them means you won’t get certified. Holding a matching third-party certificate exempts you from some questions in that section.

Source: Build UK, CAS Question Set Version 5

BS 99001 covers the widest scope. Holding it exempts you from Quality questions 125 to 134 and every Building Safety question, 135 to 154. Other exemptions depend on the work you do, such as employing no subcontractors or doing no work in scope of the Building Safety Act.

How do you get CAS certification?

CAS certification, which many subcontractors call accreditation, comes from choosing a Recognised Assessment Body, picking an audit level, completing the question set with evidence and renewing every year.

Choose a Recognised Assessment Body

Seven Recognised Assessment Bodies certify suppliers to CAS: Achilles, Compliance Chain, Constructionline, CQMS, SCCS, Smas Worksafe and Veriforce CHAS. Each body has its own fee structure, so ask more than one for a quote at your audit level.

Pick a desktop or site-based audit

A desktop audit checks your evidence remotely, and a site-based audit brings an auditor to your premises to verify how you put your policies and procedures into practice. You choose one level, not both, based on factors including trade, size and the requirements of the contractors and clients you work for.

Complete the question set, upload your evidence and renew every year

You complete the question set on your assessment body’s platform and upload documents for certain questions. Examples include your last two years of accounts for question 27, insurance certificates for questions 28 to 33, and an SSIP or ISO 45001 certificate for question 71. Put your certificate anniversary and every time-critical expiry date on the same calendar as your contract renewals and tender deadlines, so an insurance renewal doesn’t land in the middle of a live tender.

How did CAS replace PAS 91 in public sector pre-qualification?

BSI withdrew PAS 91 on 21 April 2023. PAS 91 was the British Standards Institution’s specification for construction pre-qualification questionnaires. PPN 03/24, published on 27 March 2024 and replacing PPN 03/23, says contracting authorities should use CAS in place of the standard Selection Questionnaire for works contracts, including mixed contracts that include supplies and services.

Under the Procurement Act 2023, the procurement specific questionnaire keeps the same approach: public contracts for works should continue to use the CAS questions, including mixed contracts. A supplier certified by a Recognised Assessment Body is deemed to meet stage 1 pre-qualification, so the authority can focus on project-specific questions such as financial stability and insurance.

What should subcontractors do before CAS version 6 arrives?

Before version 6 arrives on 1 November 2026, confirm which version of the question set your assessment body will use at your next renewal, and get your competence and supervision evidence ready. For most subcontractors the change is small: three competence questions move to Quality, and you may already be answering them. If you install electrical, heating, plumbing or cooling systems, you will probably still complete Building Safety as well.

Name one person who owns CAS evidence, check every time-critical expiry date, and match each subcontractor’s insurance and competence records to the contracts they work on, so a lapse shows up before a bid goes in. The right preparation depends on your trade, your assessment body and the contractors you work for, so check the published question set on 1 November before you change anything.

If you want to see how Joblogic keeps compliance documents and subcontractor records together ahead of your next renewal, book a demo with our team.

Frequently asked questions about the Common Assessment Standard

When does CAS version 6 come into effect?

Build UK publishes version 6 of the Common Assessment Standard on 1 November 2026. Until then, all suppliers going through certification complete questions 135, 136 and 138, even where the other dutyholder questions don’t apply.

What should I do now ahead of CAS v6?

If you’re certifying or renewing before 1 November 2026, complete questions 135, 136 and 138 even if the rest of Building Safety doesn’t apply to you. After 1 November they sit in Quality for every supplier. Build UK’s statement doesn’t say whether certificates already issued need re-auditing, so ask your assessment body.

Do scaffolding and temporary works suppliers still complete Building Safety?

Not from version 6, unless they carry out building work. Build UK says they still complete the competence questions, because those move to Quality and apply to every supplier.

Do electrical, HVAC and plumbing and heating subcontractors complete the Building Safety section?

Most will probably complete it. Question 22 in version 5 asks whether you provide or extend controlled services or fittings, and a yes means you complete Building Safety. The scaffolding and temporary works change doesn’t apply to your trades, and your assessment body confirms which questions apply to you.

Does BS 99001 exempt me from the moved questions?

Under version 5, BS 99001 exempts you from every Building Safety question and from Quality questions 125 to 134. Build UK hasn’t said how exemptions apply to questions 135, 136 and 138 once they move to Quality, so check the version 6 question set when it’s published on 1 November.

What is CAS accreditation for subcontractors?

CAS accreditation is the common name for CAS certification, which is Build UK’s term. A subcontractor gets it by completing the question set and passing an audit with a Recognised Assessment Body, and the certificate is valid for one year from the date of issue.

Do subcontractors need CAS certification?

It depends on who you work for. Build UK says central government departments and wider public sector bodies should use CAS to pre-qualify companies for construction works contracts, and a growing list of contractors and clients accept it without specifying a particular assessment body. Check what your customers ask for before you apply.

How much does CAS certification cost?

CAS has no single price, because each Recognised Assessment Body has its own fee structure. Build UK says cost details are available directly from each body, so ask more than one for a quote at your audit level. If you hold CAS from more than one body, Build UK suggests reviewing whether you still need both.

What is the difference between CAS and SSIP?

Safety Schemes in Procurement (SSIP) certificates cover health and safety, while CAS is a full pre-qualification standard across 10 sections. The two connect in the Health and Safety section, where an SSIP certificate exempts you from questions 73 to 85 and 86 to 110. SSIP doesn’t exempt you from questions in the other nine sections.

Can you share CAS data with more than one assessment body?

Yes. Once you’re certified by one body, you can share your data with as many Recognised Assessment Bodies as you need by completing each body’s data sharing form, and you must email the body that certified you to give permission. Sharing covers 33 key questions, and no documents are shared.

Do micro-businesses get a lighter CAS assessment?

Yes. The assessment standards for certain questions are revised for micro-entities, and micro-businesses can still choose to complete the relevant questions to the full standard. A company is a micro-entity if it meets at least two of three conditions for accounting periods beginning on or after 6 April 2025: turnover of no more than £1 million, a balance sheet total of no more than £500,000, and no more than 10 employees on average.