What is the difference between certification and accreditation?

Certification means your organisation has been independently assessed against a defined standard and issued a formal certificate. Accreditation is the formal recognition that a certification body itself is competent to carry out assessments — typically granted by a national body like UKAS. NAS operates as an independent certification body aligned with ISO/IEC 17021 principles, assessing organisations and issuing formal certificates based on documented evidence.

Do I need certification to work on construction sites in the UK?

There is no legal requirement to hold a specific certification. However, most principal contractors, housing associations, councils, and NHS trusts require evidence of compliance before awarding work. NAS certification provides that evidence — independently assessed and publicly verifiable, with real assessor review of your actual documents.

How much does NAS certification cost?

NAS Basic is £349/year, NAS Bronze is £749/year, NAS Silver is £950/year, and NAS Gold is £1,150/year. Pricing is flat — never scaled by headcount or turnover. Loyalty discounts apply from year 2 (5% rising to 20% by year 5).

How long does NAS certification take?

Most NAS assessments complete within 3-5 working days of evidence submission. The full process from application to certificate typically takes 1-3 weeks.

What is ISO 17021 and why does it matter?

ISO/IEC 17021 is the international standard governing bodies that certify management systems. It requires independent assessors, separation of assessment and decision-making, and evidence-based decisions. NAS operates its certification scheme in alignment with these principles.

How long is NAS certification valid?

NAS certification is valid for one year and is renewed annually. The annual renewal cycle ensures your compliance is kept current. Loyalty discounts apply from year 2.

NAS Basic, Bronze, Silver and Gold — Tier Comparison

Quick Answer

What is the difference between NAS Basic, Bronze, Silver and Gold?

The four NAS tiers differ in the number of compliance areas assessed and the depth of the evidence review. NAS Basic covers 4 core areas. NAS Bronze covers 9. NAS Silver covers 14. NAS Gold covers 22 — including Building Safety Act compliance, net zero, modern slavery and Common Assessment Standard (CAS) alignment with 10 procurement-specific modules.

NAS Basic — £349/yr

4 compliance areas. Sole traders, micro businesses, domestic and small commercial work.

Health and safety policy
RAMS documentation
Public liability insurance
Employers' liability insurance
Workforce training records

NAS Bronze — £749/yr

9 compliance areas. Small to medium contractors targeting housing association, local authority and commercial supply chains.

All Basic areas
Data protection (GDPR)
Equality & diversity policy
Employment practices evidence
Anti-bribery statement

NAS Silver — £950/yr

14 compliance areas. Established contractors targeting NHS, public sector, main contractor and housing framework work.

All Bronze areas
Environmental policy and evidence
Corporate governance documentation
Risk management framework
Supply chain management controls
Quality management evidence

NAS Gold — £1,150/yr

22 compliance areas. Contractors tendering for major frameworks, public sector contracts and housing association capital programmes.

All Silver areas
Building Safety Act compliance
Net zero / carbon policy
Modern slavery statement
Common Assessment Standard (CAS) alignment
10 procurement-specific modules

Which Tier is Right for Your Business?

The right tier depends on the contracts you are targeting and the compliance evidence you already have in place.

NAS Basic or Bronze — suitable for sole traders and small businesses targeting domestic, small commercial or basic local authority work.
NAS Bronze or Silver — most commonly expected for housing association reactive maintenance, local authority supply chains and NHS facilities work.
NAS Silver or Gold — appropriate for contractors targeting larger framework contracts, public sector procurement or main contractor supply chains.
NAS Gold — recommended for contractors tendering for major procurement frameworks where CAS alignment is referenced or where Building Safety Act compliance evidence is required.

Annual Renewal

All NAS certification tiers are renewed annually. Renewal requires submission of updated evidence and a fresh independent review. This ensures that your NAS certificate reflects your current compliance position, not just where you were when you first applied.