Which Construction Accreditation Do I Need? A Decision Guide for UK Subcontractors

If a main contractor or a council has just told you to "get accredited" before you set foot on site, the question which construction accreditation do I need has exactly one honest answer: it depends entirely on the wording of what they asked for — not on which scheme is best. Read the email again. The difference between the words "SSIP", "CHAS" and "Common Assessment Standard" is the difference between a few hundred pounds and a full pre-qualification audit.

TL;DR

If the client just says "SSIP" or "an SSIP-approved scheme", you can pick the cheapest SSIP member scheme that covers your dutyholder role — they all assess against the same HSE-backed core criteria and mutually recognise each other. If the client names one scheme ("we need you on CHAS"), get SSIP once with any member scheme, then use the Deem to Satisfy route into theirs at a reduced fee rather than paying twice. If the client says Common Assessment Standard, or the money is public sector, SSIP alone will not clear the gate — you need a CAS-certified tier such as Constructionline Gold, CHAS Elite or Smas Worksafe Pro. Fee bases start around £345 for a standalone SSIP certificate and £399 a year plus a one-off joining fee at Constructionline, both banded by size or turnover. The admin that no scheme solves is the bit that bites: different renewal dates, the same evidence re-uploaded per portal, and CAS data sharing that needs a form per assessment body.

What actually decides which accreditation you need?

The useful reframe is this: accreditation schemes are not qualifications, they are gate keys cut to a buyer's specification. Nobody is grading your trade. A buyer has a procurement policy that says "stage 1 pre-qualification must be evidenced by X", and your job is to buy X once, as cheaply as the policy allows, and keep it current.

That means three questions settle it, in this order:

1. What exact words did the buyer use? "SSIP" is a category. "CHAS" is a brand. "Common Assessment Standard" is a higher standard than either. They are not interchangeable.
2. Is there public money or a Tier 1 main contractor behind it? Build UK states that central government departments and wider public sector bodies should use the Common Assessment Standard to pre-qualify suppliers in line with PPN 03/24, which is why so many public-sector and Tier 1 PQQs now name CAS specifically.
3. How many different gates will you go through in the next 12 months? One client asking for one scheme is a cheap problem. Four clients asking for four schemes is a diary problem, and that is where the real cost sits.

Which accreditation do I need if the client just says "SSIP"?

If the request is simply for SSIP or "SSIP-approved", you get to choose the provider, and price is a legitimate deciding factor. SSIP is an umbrella body, not a scheme you join directly: according to SSIP's own supplier guidance, all member schemes assess against the same SSIP Core Criteria (approved by the HSE) and agree to mutually recognise each other, so a certificate from one is designed to satisfy the others through the Deem to Satisfy (DtS) process.

Two practical caveats before you shop on price alone. First, check the scheme covers your dutyholder role — Contractor, Designer, Principal Designer — because that is category-specific, not universal. Second, note the membership type. SSIP distinguishes Registered Members from Certification Body Members: Registered Member certificates get two-way mutual recognition with all other Registered Members, while Certification Body routes (ISO 45001 plus the UKAS SSIP sector scheme audit) are described as one-way. If you expect to be pushed toward several different schemes, the two-way route keeps more doors open.

Our guide to the cheapest SSIP scheme goes through the fee bases in detail, and SSIP mutual recognition explained covers how DtS actually works in the portal.

Which accreditation do I need for public sector or Common Assessment Standard work?

This is the tier most subcontractors get caught out by, because an SSIP certificate feels like it should be enough and isn't. The Common Assessment Standard is Build UK's industry-agreed question set covering far more than health and safety — corporate and professional standing, financial, environmental, quality, information security, and a now-mandatory Building Safety section. Build UK confirms companies are certified once a year by a Recognised Assessment Body, with two levels: desktop and site-based.

The routes to CAS run through the schemes you already know. Constructionline states that for the desktop audit you need to be verified to Gold with the CAS question set, and to Platinum for the on-site audit (Constructionline supplier FAQs). CHAS positions Elite as its CAS package, covering 13 risk management areas (CHAS products and packages). Smas offers CAS as Worksafe Pro (Smas SSIP page).

One genuinely useful bit of relief for small firms: Build UK states that for companies meeting the micro-business criteria, the assessment standards are applied in a proportionate way. If you're a five-man firm being asked for CAS, you are not being marked against the same evidence bar as a 200-strong regional contractor — say so if an assessor asks for something that reads as corporate boilerplate.

What does each level actually buy you?

TODO(verify) — the specific Constructionline Gold annual fee for a sub-£1m turnover band is quote-based and not published as a flat figure; treat £399 as the entry point across the membership range, not a Gold price.

Worked example: a 12-engineer M&E firm with two clients asking for two different things

Say you run a 12-engineer electrical and mechanical firm. Client A, a facilities management outfit, wants "SSIP" for a recurring commercial maintenance contract worth around £5k a year. Client B, a Tier 1 fit-out contractor, sends a PQQ demanding the Common Assessment Standard.

The wrong move — and the common one — is to answer each request separately: buy CHAS because Client A's email mentioned it in passing, then buy Constructionline Gold in a panic three months later because Client B's PQQ won't submit without CAS. You now hold two memberships, two renewal dates, and you've evidenced the same insurance certificates and health and safety policy twice.

The cheaper sequence is to buy the highest tier anyone actually requires first, then work downwards using recognition. Get CAS through one Recognised Assessment Body; that certification includes an SSIP-standard health and safety assessment inside the wider question set, which satisfies Client A's request too. If Client A later insists on a specific SSIP brand you don't hold, that's a Deem to Satisfy application at a reduced fee — not a second full assessment.

Order of operations, then: highest requirement first, recognition second, second memberships only when a buyer genuinely will not accept anything else. Our guide on whether you need more than one accreditation works through the cases where a second scheme is unavoidable, and the CHAS vs SafeContractor vs Constructionline comparison sets the three side by side.

What none of these schemes solve for you

This is the part the scheme websites are quiet about, and it's worth knowing before you choose, because it shapes which route is least painful in year two.

Deem to Satisfy creates a dependency, not a duplicate. SafeContractor's own SSIP guidance is unusually clear on this: where your certification comes via an existing SSIP certificate, that certification is suspended when your original SSIP member certificate expires, and only the original certificate appears on the SSIP portal (SafeContractor SSIP page). In plain terms: miss one renewal and you can lose two certificates at once, and the second one goes quietly.

CAS data sharing isn't automatic. Build UK confirms that certified companies can share their data with other Recognised Assessment Bodies — but you complete a data sharing form for each body you want to share with, and you must email the body that originally certified you to give permission. It's genuinely useful, and it's still admin you have to initiate.

Different schemes, different clocks. SSIP certificates, CAS certification and scheme memberships each run annually from their own issue date, and time-critical documents like insurance certificates expire independently of all of them. Keeping track of them is the residual pain — see accreditation renewal deadlines for how to build a calendar that doesn't rely on remembering.

How to decide in ten minutes at the kitchen table

1. 1
   Find the exact wording. Open the client's email or PQQ and highlight the words used: SSIP, a brand name, or Common Assessment Standard. Everything follows from this.
2. 2
   Check for public money. If it's a council, housing association, NHS trust or central government framework, assume the Common Assessment Standard is the target, per Build UK's PPN 03/24 position.
3. 3
   List every buyer for the next 12 months. Write down what each one demands. Buy for the highest requirement on the list, not the loudest one.
4. 4
   Get quotes on the same basis. Fees are banded by employee count or turnover, so give every scheme the same headcount and turnover figures or the quotes aren't comparable.
5. 5
   Ask one question before paying: "Does this include SSIP and CAS, or just SSIP?" Get the answer in writing, then diarise the renewal date the day the certificate lands.

Frequently Asked Questions

Is SSIP the same as CHAS?

No. SSIP is the umbrella body that sets the core criteria and runs mutual recognition between member schemes; CHAS is one of those member schemes. If a client asks for SSIP, any member scheme covering your dutyholder role should do — if they ask for CHAS by name, that's a brand preference you can often meet through Deem to Satisfy rather than a second full assessment.

Do I need the Common Assessment Standard as a small subcontractor?

Only if a buyer asks for it — but increasing numbers do, because Build UK states that central government and wider public sector bodies should use the Common Assessment Standard to pre-qualify suppliers under PPN 03/24. Build UK also confirms the assessment standards are applied proportionately for companies meeting the micro-business criteria, so a very small firm is not judged against a large contractor's evidence bar.

Is Constructionline Bronze SSIP-approved?

Constructionline states that SSIP is now included across its Bronze, Silver, Gold and Platinum memberships, delivered through Once For All Health & Safety, with a Deemed to Satisfy option if you already hold an SSIP certificate elsewhere. What Bronze does not give you is the Common Assessment Standard — Constructionline says that requires Gold for the desktop audit and Platinum for the on-site audit. See our Gold vs Silver vs Bronze breakdown for what changes at each tier.

What's the cheapest way to get accredited?

Buy the lowest tier that the buyer's wording actually requires, from the scheme with the cheapest band for your headcount, then use Deem to Satisfy at a reduced fee for any additional scheme a different client insists on. Smas publishes SSIP certificates from £345 and Constructionline publishes annual membership from £399 plus a one-off joining fee by turnover band; both are starting points, so get quotes using identical headcount and turnover figures.

Can I hold accreditation with more than one scheme at once?

Yes, and plenty of subcontractors do because different clients name different schemes. Just be aware that where the second certificate came via Deem to Satisfy, it can be suspended when the original SSIP certificate expires — so the two renewals are linked, and the cheaper certificate is the one that depends on the other.

Last reviewed: 14/08/2026. Fees and scheme scopes change without much announcement, so confirm the current figure and tier scope with the scheme before you pay. This guide is informational and neutral — it isn't legal or compliance advice, and for anything specific to your contract or dutyholder role, ask the scheme or a qualified professional. Start with the scheme comparison hub for the full side-by-side, or the Common Assessment Standard explained if a PQQ has just landed asking for CAS.