Why Subcontractor Compliance Matters
Managing subcontractor compliance is one of the most time-consuming and risk-laden aspects of running a construction project. Get it right, and your project runs smoothly with qualified workers, proper insurance, and correct tax treatment. Get it wrong, and you face potential fines, project delays, and legal liability.
This guide provides a practical overview of the key compliance areas that main contractors need to manage when working with subcontractors and labour suppliers.
The Construction Industry Scheme (CIS)
CIS is the HMRC scheme that governs how payments are made to subcontractors in the construction industry. As a main contractor, you're required to register with HMRC as a contractor under CIS, verify your subcontractors' registration status, and make deductions from payments to unregistered or unverified subcontractors.
The standard CIS deduction rate is 20% for registered subcontractors and 30% for unregistered ones. Gross payment status allows qualifying subcontractors to receive payments without deductions, but this requires meeting strict turnover and compliance criteria.
Monthly CIS returns must be submitted to HMRC, and deductions must be paid over by the 22nd of the following month. Failure to comply can result in penalties, interest charges, and — in serious cases — criminal prosecution.
One of the advantages of using a labour agency rather than direct subcontractors is that CIS often doesn't apply. When you hire workers through an agency, you're paying the agency for a service, and the agency handles the employment and tax obligations. This significantly simplifies your CIS reporting.
Insurance and Liability
Every subcontractor on your site should carry adequate insurance. The minimum requirements are typically employers' liability insurance (mandatory for anyone with employees), public liability insurance (to cover damage to third parties), and professional indemnity insurance (for design or advisory roles).
Checking insurance isn't a one-off task. Policies expire, and a subcontractor who was properly insured when they started on your project may not be insured six months later. Implement a system for checking insurance at the start of each project phase and diarising renewal dates.
The amounts of cover should be appropriate for the risks involved. A labourer doing site clearance has a different risk profile to an electrician installing a distribution board. Most main contractors require a minimum of £5 million public liability and £10 million employers' liability, but your specific requirements may vary.
Keep copies of all insurance certificates on file. If there's an incident and you can't demonstrate that the subcontractor was properly insured, you may find yourself bearing the liability even if the fault lies entirely with the subcontractor.
Qualifications and Competence
Verifying that subcontractors and their workers are qualified for the work they're doing is both a legal requirement (under CDM 2015) and basic good practice.
CSCS cards should be checked for every operative on site. Don't just check that they have a card — check that the card type is appropriate for the work being done. A labourer's green card doesn't qualify someone to do electrical work, for example.
Trade-specific qualifications should be verified against original certificates or through the relevant awarding body. NVQs, City & Guilds, and other qualifications can be verified online in most cases.
For specialist work (gas installation, electrical testing, asbestos removal, etc.), additional certifications are required. Gas Safe registration, 18th Edition certification, and HSE-licensed asbestos contractor status are all examples of work-specific requirements that must be verified before work commences.
Labour agencies typically handle qualification verification as part of their vetting process. When using 4A Trades, all operatives are CSCS-carded, qualification-verified, and right-to-work checked before they're deployed to your site.
Health and Safety Compliance
Under CDM 2015, the principal contractor is responsible for managing health and safety on site, including the activities of all subcontractors. This means ensuring that subcontractors have adequate health and safety policies, risk assessments, and method statements for the work they're doing.
Pre-start meetings with each subcontractor should cover site rules, emergency procedures, reporting requirements, and any specific risks associated with their work area. Document these meetings and keep records.
Site inductions must be completed by every person who enters the site, including subcontractor workers. The induction should cover site-specific hazards, welfare facilities, emergency procedures, and relevant site rules.
Monitoring compliance throughout the project is essential. Walk-rounds, toolbox talks, and regular review meetings help maintain standards and catch issues before they become problems.
Simplifying Compliance With the Right Approach
The compliance burden grows with the number of subcontractors and labour suppliers you use. Every additional company you work with means additional CIS reporting, additional insurance checks, additional qualification verification, and additional health and safety management.
Consolidating your labour supply through fewer, more reliable suppliers reduces this burden significantly. If you can get all your labour through one or two trusted agencies rather than ten different subcontractors, the administrative saving is substantial.
At 4A Trades, we supply 20 different trade categories through a single account. One point of contact, one weekly invoice, and one set of compliance documentation. We handle the employment law, the tax obligations, the qualification verification, and the insurance — so you can focus on running your project.