ARB and PI insurance: what the Architects Code requires
Reviewed by Matthew Bartlett, Director, Apex Insurance Brokers Limited · Last reviewed 2026-08-05
If you are a registered architect in the UK, professional indemnity insurance is not optional. It is a condition of the professional standards set by your regulator. But architects are often surprised to learn that the Architects Code does not name a fixed minimum sum insured. Instead it uses a principle-based test. This page explains what that test is, why ARB frames it that way, and how to decide what level of cover is defensible for your practice.
Who ARB is — and what the Code actually says
ARB is the independent, statutory regulator of the architects' profession in the United Kingdom, established under the Architects Act 1997. It maintains the Register of Architects and protects the title "architect", which is protected in law. This is distinct from the Royal Institute of British Architects (RIBA), which is a professional membership body, not the statutory regulator.
ARB publishes the Architects Code: Standards of Conduct and Practice, which every registered architect must follow. The Code includes a standard on insurance. In plain terms, it requires that architects arrange adequate and appropriate insurance cover for themselves, their practice and their employees, and that they are able to demonstrate this when asked. ARB supports the Code with separate published guidance on professional indemnity insurance, which it updates from time to time.
The key point for compliance: the obligation is expressed as a standard of adequacy, not as a single monetary minimum written into the Code. Do not assume there is one "official" figure that makes you compliant. There isn't. Always check ARB's current published guidance for the detail that applies at the time you renew.
What "adequate and appropriate" means in practice
Because the requirement is principle-based, the responsibility sits with you to hold a level and type of cover that genuinely matches your exposure. "Adequate" is about the amount — is the limit of indemnity large enough to meet a realistic worst-case claim? "Appropriate" is about the fit — is the type of cover, and its terms, right for the work you actually carry out?
In practice, a proportionate assessment looks at factors such as:
- The value of the projects you work on. A practice designing high-value commercial or residential schemes carries far greater potential liability than one doing small domestic extensions.
- The nature of your services. Full design and contract administration typically carries more exposure than limited-scope advisory or feasibility work.
- Your contractual commitments. Client contracts, appointments and collateral warranties often specify a minimum level of PII you must hold and maintain for a set period.
- Your fee income and practice size. Larger turnover and headcount generally point to higher appropriate limits.
- Historic and legacy work. Claims can arise years after a project completes, so past work still shapes what is adequate today.
ARB expects you to be able to justify the decision you reached. Holding a low limit simply because it is cheaper, when your work plainly exposes clients to larger losses, is unlikely to meet the standard.
Not sure what limit is defensible for your practice? We arrange architects' PII sized to your real exposure — not a one-size template.
Get a PI quote →Principle-based vs fixed-minimum: how it compares
It helps to understand how ARB's approach differs from a prescribed floor. Some professions and some contract requirements set an explicit minimum sum insured; ARB's Code sets a standard of adequacy you must meet and evidence.
| Feature | ARB "adequate and appropriate" standard | A fixed statutory minimum |
|---|---|---|
| Set figure? | No single prescribed limit in the Code | Yes, a named amount |
| Who decides the level? | You, based on your risk, with cover you can justify | The rule sets it for everyone |
| Flexibility | Scales up or down with the work you do | Same floor regardless of exposure |
| Your obligation | Judge, arrange and evidence appropriate cover | Meet the stated number |
Common commercial limits of indemnity are offered in bands such as £1m, £2m or £5m per claim (and higher), but these are generic market options — not an ARB-set minimum. The right one for you depends on the factors above and on what your client contracts demand.
Cover terms that matter beyond the headline limit
"Appropriate" is not only about the number. A few structural features of a PII policy strongly affect whether cover will actually respond:
- Claims-made basis. Most PII responds to claims made during the policy period, so cover must be kept live continuously — gaps are dangerous.
- Run-off cover. Claims can surface long after work ends or a practice closes. Maintaining run-off cover after you stop practising is an important part of ongoing responsibility; ARB's guidance addresses continuing to hold cover in these situations.
- Limit basis — each claim vs aggregate. "Each and every claim" cover behaves very differently from an annual aggregate limit. Check which you have.
- Retroactive date. This governs how far back your past work is covered. A restricted retroactive date can leave legacy projects exposed.
- Exclusions and conditions. Fire safety, cladding and certain high-risk work can attract specific terms or exclusions worth reviewing carefully.
An adequate limit sitting on top of the wrong terms can still leave a real gap. This is where broking advice earns its keep. Ask us to review your current wording against the work you actually do.
How to demonstrate compliance
Because ARB may ask you to show that your cover is adequate and appropriate, keep a simple, dated record of how you reached your decision: the limit you chose, the reasoning tied to your project values and services, any contractual minimums you had to meet, and confirmation that cover is in force. Review it at each renewal and whenever the nature or scale of your work changes materially. Treat the assessment as a live judgement, not a box ticked once.
Common questions
Does the Architects Code state a minimum amount of PI cover?
No. The Code requires "adequate and appropriate" insurance rather than naming a single pound figure. ARB publishes supporting guidance that you should check for current detail, but the level you hold is a judgement based on your own exposure.
Is ARB the same as RIBA?
No. ARB is the statutory regulator established under the Architects Act 1997 and maintains the Register of Architects. RIBA is a professional membership body. The Architects Code and the PII obligation come from ARB.
Do I still need cover after I stop practising?
Very often, yes. Because claims can arise years later and most PII is claims-made, run-off cover is an important consideration when you close a practice or retire. Check ARB's current guidance and speak to your broker before letting cover lapse.
Apex Insurance Brokers Limited is authorised and regulated by the Financial Conduct Authority (FRN 724952). This guide is general information, not advice on a specific policy or a substitute for your policy wording.