CHAS — the UK's most-recognised H&S pre-qualifier.
The Contractors Health and Safety Assessment Scheme is a third-party pre-qualification body that vets contractors on health & safety, training, insurance and competence. CHAS Premium Plus is the gold standard — typically required by local authorities, NHS trusts and major construction PQQs. The premium offered by CHAS contractors is they bring auditable safety controls before tools touch site.
What is CHAS accreditation and why does it matter?
CHAS (Contractors Health and Safety Assessment Scheme) is the UK's largest third-party H&S pre-qualification body. CHAS-accredited contractors have submitted policies, training records, insurances, accident statistics and competence evidence to a CHAS auditor and passed annual review. CHAS Premium Plus is the gold tier — typically required by local authorities, NHS trusts, MOD framework, and most major construction PQQs. Equivalent recognised schemes: SafeContractor, ConstructionLine, Acclaim.
Approximate UK contractor base across CHAS Standard and Premium tiers.
Annual renewal — full evidence pack re-submitted each year.
CHAS has operated since 1997, originally founded by London Boroughs HASPA.
CHAS — the terms that matter
Plain-English definitions for the 4 terms you'll see in any quote, certificate or enforcement notice for CHAS Accreditation.
- CHASCHAS
- Contractors Health and Safety Assessment Scheme — UK's largest third-party H&S pre-qualification body. Owned by Veriforce.
- Common Assessment StandardCAS
- A construction industry-wide standard for contractor pre-qualification, supported by Build UK + LASBA. CHAS Premium Plus aligns with CAS.
- CDM 2015CDM
- Construction (Design and Management) Regulations 2015 — UK's principal construction H&S regulations. CHAS audits CDM compliance among other things.
- PQQPQQ
- Pre-Qualification Questionnaire — the buying organisation's due-diligence form. CHAS accreditation typically discharges most of the H&S section.
How to verify CHAS accreditation on a contractor
Five steps from instruction to certificate. Total time: 3m.
01
Ask for cert number
Before booking
CHAS issues a certificate number per contractor. Ask for it before commissioning major work.
02
Verify on register
2 minutes
Search the CHAS public register at CHAS.co.uk. Confirm the certificate number, accreditation tier (Standard / Premium / Premium Plus), and validity date.
03
Check tier
Before booking
For local-authority and NHS-framework work, you typically need Premium Plus. For lower-risk domestic work, Standard or SafeContractor equivalent is fine.
04
Match scope to risk
Before scoping
CHAS audit is broad — H&S, insurance, competence, training. Lighter-risk domestic jobs may not need this depth; ask why CHAS would matter.
05
Cross-trade alignment
Multi-trade work
On any CDM project (5+ days, 20+ workers, 500+ person-days), every contractor on the site should hold CHAS or equivalent — principal contractor checks at engagement.
CHAS Accreditation. Done compliant.
Every TradeMatch-listed tradesperson covering CHAS Accreditation carries the relevant scheme registration. Verified at onboarding, re-verified annually, certificates posted to you within 30 days of any notifiable work.
CHAS vs SafeContractor vs ConstructionLine — H&S schemes
Side-by-side comparison of the compliant route versus the unregistered shortcut. Most rows trace a straight line from regulation to financial exposure.
| Scheme | Coverage | Tiers | Renewal |
|---|---|---|---|
| COMPLIANT — RECOMMENDEDCHAS Premium Plus | CAS-aligned + financial + EDI + supply chain | 3-tier (Standard / Premium / Premium Plus) | Annual |
| SafeContractor | H&S focus; CAS Pass option available | 2-tier | Annual |
| ConstructionLine | Buyer-side — common in tendering, links to CAS | Bronze / Silver / Gold / Platinum | Annual |
| Acclaim | CAS-aligned, smaller installer base | 1-tier | Annual |
Source: Build UK Common Assessment Standard, CHAS group documentation 2024.
The questions homeowners ask before they commit.
Is CHAS legally required?
No — CHAS is a private accreditation. The legal requirements are under HSWA 1974 + CDM 2015 directly. CHAS is the most efficient way for buyers (especially public-sector buyers) to discharge their duty to verify contractor competence — but a non-CHAS contractor can still be perfectly competent.
How much does CHAS accreditation cost a contractor?
Standard tier from £475/yr; Premium Plus from £790/yr (smaller business). Annual audit takes 3–7 days of a contractor's admin time to compile evidence. Most contractors recoup the fee from a single mid-size local-authority or NHS framework job.
What's the difference between CHAS Standard and Premium Plus?
Standard covers core H&S + insurance + competence. Premium adds CAS-aligned financial standing + EDI + supply chain. Premium Plus adds extended due-diligence on environmental management + quality + cyber. Local-authority and NHS framework PQQs typically demand Premium Plus.
Do small builders need CHAS?
For domestic-only homeowner work, no — CHAS is overkill. For commercial work, public-sector framework, or multi-trade construction projects (especially under CDM 2015), yes — CHAS or equivalent is generally a buyer requirement. Small builders pursuing local-authority work routinely hold CHAS.
Is CHAS the same as SSIP?
CHAS is one of the schemes audited under SSIP (Safety Schemes in Procurement) — a meta-recognition group covering CHAS, SafeContractor, ConstructionLine and ~10 others. SSIP "deeming" means accreditation in any one scheme is generally accepted by buyers asking for any other.
Can a homeowner ask for CHAS accreditation?
Yes — for any work over £50k or with significant risk (loft conversion, double-storey extension, demolition, asbestos handling), CHAS-accredited contractors give you auditable evidence the contractor takes H&S seriously. For routine domestic work — single-storey rear, kitchen rewire, bathroom — CHAS is overkill.
Going deeper.
H&S evidence, on every job.
TradeMatch contractors hold CHAS, SafeContractor or equivalent SSIP accreditation. Auditable evidence packs ready on request.