Tendering and estimating, 29 October 2026
Constructionline, CHAS, SafeContractor or SMAS: which you need and what they cost
You need whichever scheme the main contractor or client asking for it names. If they ask for "SSIP", any SSIP member scheme will do, and the cheapest starts around £345 to £489 a year (October 2026). If they ask for the Common Assessment Standard, you need a higher tier: CHAS Elite or Constructionline Gold. Don't buy one until a buyer asks.
What's the difference between SSIP, CAS and PAS 91?
SSIP (Safety Schemes in Procurement) is an umbrella body that sets a common health and safety standard and lets member schemes recognise each other's certificates. It isn't an assessment itself. CHAS, Constructionline, SafeContractor and SMAS Worksafe each sell an SSIP-recognised assessment.
The Common Assessment Standard (CAS) is a wider prequalification question set developed by Build UK. Beyond health and safety it covers areas such as finance, quality, environment and building safety. CHAS describes it as covering 13 risk areas.
PAS 91 was the old standard prequalification questionnaire. BSI withdrew it in April 2023, and the government's Procurement Policy Note 03/24 removed the reference to it, steering public sector construction buyers to CAS instead.
Which one do you need?
The one your buyer names. Main contractors each have a preferred scheme, and many accept any SSIP certificate. Ask before you spend.
No buyer is asking, so it would be a cost with no return. Get your health and safety policy, risk assessments and insurance in order so you can apply quickly when one does.
Check first whether they accept Deem to Satisfy from another SSIP scheme you already hold. If not, buy theirs at the lowest tier that meets their requirement.
That means CHAS Elite or Constructionline Gold or above, or SMAS Worksafe Pro. Expect a bigger assessment and a higher fee than SSIP alone.
Ask whether any SSIP member scheme is acceptable. If so, choose on price, speed and support.
What do they cost?
All four price by size, so you'll pay more as you grow. These are the starting prices on each scheme's own website, as of October 2026. Check whether VAT and joining fees apply before you buy.
| Scheme | Entry option and starting price | Common Assessment Standard | Notes |
|---|---|---|---|
| SMAS Worksafe | Worksafe SSIP from £345 | Worksafe Pro (CAS) | Price depends on headcount; quote form |
| SafeContractor | Standard from £419; Assisted or Express from £499; Premier from £549 | Not stated on pricing page | One-off joining fee as well; price by employee count |
| CHAS | Standard from £429; Advanced from £659 | Elite, from £949 | Advanced adds the former PAS 91 questions |
| Constructionline | From £489 a year; free Associate level | Gold and Platinum | Bronze and above include SSIP; joining fee in year one; fee by turnover |
Constructionline's Associate level is free but is an entry listing, described as "try before you buy". Bronze is the first tier with an SSIP assessment.
What does accreditation cost in a real year?
More than the headline price, once monthly add-ons and your own time go in. Here is an illustrative example.
A yearly accreditation cost, for example
A hypothetical contractor with 14 workers, paying SafeContractor plus a monthly charge.
| Annual fee | £1,600 |
| Monthly charge£140 × 12 | £1,680 |
| Cash cost a year£1,600 + £1,680 | £3,280 |
That last line is the hidden cost. Accreditation needs a current health and safety policy, risk assessments, method statements, training records and insurance, and they have to be kept up. A groundworks firm working as a subcontractor for national main contractors told us its RAMS could run to 30 pages. The RAMS template helps, and so does one master RAMS adapted per site.
Is it worth paying for more than one scheme?
Usually not at first. SSIP's Deem to Satisfy arrangement means registered member schemes agree to accept a current approval from another registered member, so one certificate can often get you onto a second scheme with a small amount of extra information. Some schemes still ask their own questions, such as a risk profile, and charge for the Deem to Satisfy route.
Buy a second full scheme only when a buyer worth the money insists on it. Work out what the contracts from that buyer are worth to you first: if a scheme costs £1,000 a year and your margin is 15%, you need about £6,700 of work from that buyer to cover it.
Do you need accreditation for domestic work?
No. These schemes exist for commercial and public sector buyers checking their supply chain. Homeowners rarely ask for them. If you're moving from domestic to commercial work, accreditation is one of several changes: see moving from domestic to commercial work and getting on main contractors' approved lists.
For public sector tenders, check the documents for CAS and SSIP requirements before you start pricing. Where to find construction tenders and how to win social housing tenders cover the next steps, and the take-off guide covers pricing the work itself.
Where Nexley fits
Nexley is the AI back office for UK trade firms: five AI assistants run your tenders, quotes, buying, scheduling and invoicing. It connects to the tools you already work in, you run it all from WhatsApp, and you approve everything. £799 a month.
For tenders, Nexley reads the pack and lists what the buyer requires, including which accreditation, insurance levels and documents, before it prices the work against your rates. It keeps your policies and certificates on file, drafts the site-specific RAMS and flags when a certificate is due for renewal. You approve everything before it's submitted.
Common questions
Is CHAS better than Constructionline?
Neither is better in general. Both are SSIP member schemes and both offer CAS tiers. The right one is the one your main contractors ask for. CHAS's entry price starts lower, and Constructionline has a free listing level without an SSIP assessment.
Do I need SSIP to work for a main contractor?
Many main contractors ask for it to get on their approved supplier list, but there's no law that requires it. Ask the contractor what they accept, and whether they'll take Deem to Satisfy from another scheme.
Is PAS 91 still used?
BSI withdrew PAS 91 in April 2023, and public sector construction buyers are now steered to the Common Assessment Standard. Some private clients still use PAS 91-style questions. CHAS Advanced includes the former PAS 91 questions.
How long does accreditation take?
It depends on the scheme and the tier you pay for. SafeContractor's plans range from review within 20 working days on Standard to two working days on Express, as of October 2026. SMAS says certification can be achieved in as little as a day. Have your documents ready first; that's usually what slows it down.
Sources
- SSIP: What is SSIP?
- SSIP: Deem to Satisfy and mutual recognition
- CHAS: Become a CHAS compliant contractor (prices)
- CHAS: PAS 91 vs SSIP vs CAS
- Constructionline: Subcontractor memberships
- Constructionline: Gold membership
- Constructionline: Associate membership
- Constructionline: What is PAS 91 and is it still used?
- SafeContractor: Contractor pricing plans
- SMAS Worksafe: SSIP accreditation
- SMAS Worksafe: Home
- FIS: Common Assessment Standard to be used across the public sector
Every rule, rate and date above was checked against these sources on the date shown at the top.
Topic: Tendering and estimating
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