Open letter from Tier 1 Main Contractors seeks greater need for building safety compliance across their supply chains

July 2025  

17 of the UK’s top construction contractors have signed an open letter to their supply chain members, requesting they urgently meet legal competence requirements by completing the latest version of the Common Assessment Standard (CAS) questions, including its Building Safety section. 

However, with those working within the industry unsure if the Building Safety section applies to their operation, uptake in meeting the minimum legal threshold has been minimal, thus leaving main contractors conflicted as they try to take ‘all reasonable steps’ as stated by the Building Regulations 2010 to encourage higher levels of safety in the construction industry. 

Since the introduction of the Building Safety Act (2022), there has been increased change and pressure on construction contractors to legally possess the required level of organisational capability, as outlined within Part 2A – Dutyholders and Competence, of the Building Regulations 2010. 

This means their supply chain members should possess the same levels or competence.

The 17 main contractors include:

 

 

In fact, the majority of top 100 construction companies in the UK1 work with Constructionline (such as BAM, Willmott Dixon, VINCI Construction and Kier Group) and request their supply chain meet the Common Assessment Standard to work on their projects. 

By not completing the Common Assessment Standard and the Building Safety section, subcontractors risk missing out on opportunities from the above main contractors. 

 

Why are Main Contractors requesting subcontractors to meet the Common Assessment Standard? 

The Building Regulations 2010 place a duty on Main Contractors to take ‘all reasonable steps’ to ensure that: 

• • Any individual carrying out building work on a project is competent to do the work they are being asked to do. 
  • Any company carrying out building work on a project has the management policies, procedures, systems and resources in place to ensure their workers are competent – this is known as organisational capability. This applies to any subcontractor working on almost any building throughout England. 

Therefore, Main Contractors are exposed to unacceptable risks if the contract with companies without the required level of organisational capability: project delays, future building related liabilities, enforcement notices and civil/criminal action etc. 

 

In their letter, they said:  “We require our supply chain to meet the legal competence requirements of The Regulations – a mechanism to demonstrate that is by completing the Common Assessment Standard [CAS] v4.1 questions including the building Safety section.  Failure to be aligned to CAS v4.1 will result in your business being unable to tender for work after 1st October 2025.  [Continued…]

What work is covered by the Building Regulations 2010 and why is this important? 

Under the Building Regulations 2010 (as amended), “building work” must be carried out by organisations with appropriate organisational capability.  ‘Organisational capability’ is defined by regulation 11Q of The Regulations and in summary means an organisation having ‘appropriate management policies, procedures, systems and resources to ensure’ individuals under their control meet the general competence requirements of The Regulations, and the competence requirements of any principal dutyholder role they might fulfil.  You should ensure you have read regulation 11Q and understand what work is covered by its organisational capability definition.  Contrary to widespread misunderstanding, the Act’s requirements extend beyond higher-risk buildings. All building projects that fall outside of the category of a higher-risk building are also required to meet the new regulations.  [Continued…]

Next steps: How to meet our minimum supply chain requirements

Step 1: Make sure your business holds a verified Constructionline Gold or Platinum membership or other way of completing the CAS.  Step 2: Complete all relevant questions of the CAS, including the new Building Safety section. Note that opting out may risk your participation in certain work projects going forward and you will be required to provide an excellent reason to your main contractor. A reason could be that you are working on a build in Scotland, Wales or Northern Ireland where the Building Safety Act does not currently apply directly. You should check with your main contractor whether they will require this for those regions

Important: Within step 2, there will be sections that require you to submit information and relevant documents to demonstrate your CAS and Building Safety compliance. Therefore, we advise that you familiarise and complete the sections ahead of the deadline.”

 

 

What does this mean for subcontractors?

To avoid missing out on receiving work opportunities from these main contractors, they are highly encouraged to complete the Common Assessment Standard, including the Building Safety section, with Constructionline, the UK’s leading provider of the Common Assessment Standard. 

Hear directly from top principal contractors about completing the Common Assessment Standard Building Safety Section

Top principal contractors within the UK construction industry have come together to share an important message about the Building Safety Act (BSA) to their supply chain members and the wider community.

If you’re a construction subcontractor, please watch this video to see if you need to take action.

To find out more on why the Building Safety Section is required by these principal contractors watch the longer video:

How can subcontractors align with the Common Assessment Standard?

At Constructionline, we want to not only help create a safer future for all and meet the legislative requirements, but help main contractors meet the levels required to set a precedent within the industry. That also means helping subcontractors navigate the complex nature of the Building Safety Act (2022).

We want to help build a safer future for the construction industry, from build through to occupation by encouraging stakeholders to align with the Common Assessment Standard, therefore aspects of the Building Safety Act.

Our Gold and Platinum memberships include the Common Assessment questions, including the optional Building Safety section – mandatory from July 2025. They also include our BSA Assessments, demonstrating further compliance with the Building Safety Act.

Check out our Webinar, Guide and Building Safety Act Hub for guidance to navigate the legislation and complete the questions.

 

 

Why should construction subcontractors complete our Building Safety Act Assessments?

As well as aligning to the Common Assessment Standard, our Gold and Platinum memberships also include access to our optional BSA Assessments for Standard Construction and Higher-Risk Buildings. 

Obtaining a Verified Gold or Platinum membership not only boosts your prospects as a subcontractor to pre-qualify for more opportunities with main contractors mandating the Common Assessment Standard, but also helps you get verified for Pre-Qualification Questionnaire stages 1 and 2, with project-focused requirements. 

 

Next steps for subcontractors 

We want to help ensure the industry is taking the positive step towards building a safer future. Therefore, we highly encourage subcontractors to complete our Common Assessment Standard questions, AND Building Safety section. 

• Existing members: Upgrade to Gold to access and complete the questions
• New member: Register for a Gold membership. Use resources to help you complete questions on our platform