The Ultimate UK Architects PI Insurance Guide (2026)

Reading time: approximately 35 minutes. Last reviewed: May 2026.

This guide is written for principals, sole practitioners, directors and practice managers of UK architectural practices who need a single, substantive reference on professional indemnity insurance ("PI") as it applies to the architectural profession in 2026. It is structured around the rulebooks that actually govern architects: the Architects Registration Board ("ARB") Architects Code, the Royal Institute of British Architects ("RIBA") Chartered Practice criteria, and — overwhelmingly important in the post-Grenfell environment — the Building Safety Act 2022 and the Defective Premises Act 1972 as modernised by it.

We have deliberately avoided generic PI content. There is a separate Apex reference covering UK professional indemnity insurance across all professions (see the Ultimate UK PI Guide 2026) and a dedicated piece on claim management (see the Ultimate UK PI Claim Management Guide 2026). This document is the architects-specific companion to both.

This is a technical reference written by an FCA-authorised UK insurance broker. It is not legal advice, and it is not personal recommendation under FCA rules. Where you need a binding view on a specific contract, claim, ARB investigation or BSA dutyholder question, take qualified legal advice and speak to your broker before you act.

Table of contents

1. Why architects' PI is a distinct discipline in 2026
2. ARB Code Standard 8 — adequate and appropriate insurance, clause by clause
3. ARB minimum PI requirements and the renewal declaration
4. RIBA Chartered Practice criteria and how they interact with ARB
5. Selecting a limit — fee-band sliding scale and project-value approach
6. Building Safety Act 2022 — section 135 and the 30-year retroactive limitation
7. Building Safety Act 2022 — section 130 Building Liability Orders
8. Building Safety Act 2022 — section 124 Remediation Contribution Orders
9. The Higher-Risk Building regime and Gateways 1, 2 and 3
10. The Principal Designer role under Building Regulations Part 2A
11. Defective Premises Act 1972 — sections 1 and 2A in the BSA era
12. RIBA Standard Form Collateral Warranty 2020 and net contribution
13. Aggregation — single-event vs each-claim, cladding, fire and RAAC
14. Design-and-build, novation and contractor-led risk transfer
15. Overseas projects, jurisdiction and US/Canada carve-outs
16. Run-off, retirement, mergers and the long tail
17. Frequently asked questions
18. About Apex Insurance Brokers Ltd

1. Why architects' PI is a distinct discipline in 2026

Professional indemnity insurance for architects is not a generic professional indemnity product with a different cover note. It is its own underwriting class, and since 2017 it has been the most heavily re-priced and re-worded specialism in the entire UK PI market. To understand the product you have to understand four overlapping pressures that have reshaped it.

The first is regulatory. The Architects Registration Board is the statutory regulator under the Architects Act 1997 and imposes mandatory PI obligations under Standard 8 of the Architects Code. ARB minimum levels are set by the Board, audited by sample at renewal, and enforceable through the Professional Conduct Committee. PI is not a commercial choice for an architect — it is a precondition of continued registration on the Register kept under section 3 of the 1997 Act.

The second is the post-Grenfell legislative reform package. The Building Safety Act 2022, the Higher-Risk Buildings (Descriptions and Supplementary Provisions) Regulations 2023, the Building Regulations etc. (Amendment) (England) Regulations 2023 (which inserted Part 2A into the Building Regulations 2010), and a wave of MHCLG and Building Safety Regulator guidance have together extended liability, created new statutory dutyholders, and given the courts powers to reach through corporate structures that did not exist before. Every one of those reforms touches architect PI.

The third is claims experience. Cladding, fire-stopping, compartmentation, balcony defects, reinforced autoclaved aerated concrete ("RAAC") in education and healthcare estates, and refurbishment defects in residential blocks have driven record loss ratios across architect PI portfolios. Underwriters have responded with cladding/fire safety exclusions, sub-limits, aggregate caps and, in some cases, withdrawal from the class entirely.

The fourth is contractual. Employers, developers, funders and contractors now demand collateral warranties, third-party rights, step-in rights, fitness-for-purpose obligations, fixed limits of liability and uncapped indemnities at a level of intensity that did not exist a decade ago. Each of those contractual positions is a potential PI exposure.

Watch out

An architect's PI policy in 2026 is rarely a single, clean limit covering all risks for all years. It is more likely a layered structure: a primary policy with possible cladding sub-limits, an excess layer, separate run-off for retired partners, and project-specific PI on the very largest schemes. Treat the policy schedule, not the certificate of insurance, as the source of truth.

1.1 Who this guide is for

Sole principals, partners and directors in UK architectural practices; in-house finance leads; risk managers in larger studios; ARB-registered architects considering retirement, sale or merger; and the procurement teams of clients who want to verify that an architect's insurance answers the contract. We have written each chapter to be useful standalone, but the BSA chapters (6 to 11) are cumulative and should be read in order.

1.2 What this guide deliberately does not do

It does not set out a recommended policy wording. It does not name insurers. It does not provide quotations or premium indications outside published industry bands. And it does not substitute for advice on a specific contract, claim or ARB matter.

Key takeaways — Chapter 1

• Architects PI is a statutory requirement under ARB Standard 8, not a commercial option.
• The product has been reshaped by BSA 2022, the HRB regime, DPA 1972 amendments and post-Grenfell claims experience.
• The policy schedule, not the certificate, governs cover; treat layered, sub-limited structures as the new norm.

Related guides: Architects PI Insurance overview — ARB Minimum Terms PI Explained — Building Safety Act PI.

2. ARB Code Standard 8 — adequate and appropriate insurance, clause by clause

Standard 8 of the Architects Code: Standards of Professional Conduct and Practice (the "Code") is the operative obligation. It sits in a Code that itself sits under section 13 of the Architects Act 1997, which gives ARB the power to make rules of professional conduct. A breach of the Code is, by definition, capable of amounting to unacceptable professional conduct under section 14.

2.1 The wording of Standard 8

Standard 8 requires registered architects to have "adequate and appropriate insurance" arrangements that cover both the architect and any business through which they are providing architectural services. The Code goes on to specify that the insurance must protect clients and others who may be affected by the architect's negligence, and that ARB expects architects to maintain cover during practice and for an appropriate period thereafter.

Four phrases in that wording carry the regulatory weight:

• "Adequate" — the limit and scope must be enough for the work actually undertaken. ARB's published guidance ties this to project value, fee income and the nature of the work, with explicit reference to higher exposures on residential, refurbishment and building safety projects.
• "Appropriate" — the type of cover must match the work. PI on a personal-injury household policy does not qualify; civil liability "professional indemnity" cover from an authorised insurer is the baseline.
• "Any business through which" — Standard 8 follows the architect across vehicles. A registered architect operating through a limited company, an LLP or as a sole trader is responsible for the practice's PI, not just their personal cover.
• "An appropriate period thereafter" — run-off is mandatory. We treat this in detail in Chapter 16.

2.2 "Adequate and appropriate" — what ARB expects in evidence

ARB does not publish a tariff. It does publish an Insurance Guidance note that sits alongside the Code and is read with it. The guidance makes clear that:

• The architect must take a reasoned, recorded decision on limit and scope.
• The decision must consider the size and value of projects, the architect's role (lead consultant, sub-consultant, design-and-build novated, Principal Designer), the form of contract, the duration of liability under that contract, and the nature of any collateral warranties.
• The architect must understand the policy's main exclusions and sub-limits and be able to demonstrate that the resulting cover is in fact adequate for the work in hand.

In a Professional Conduct Committee ("PCC") investigation, ARB does not typically argue that any specific limit is correct. It argues that the architect has either (a) failed to hold cover, (b) held cover with material gaps relative to the work undertaken, or (c) cannot evidence a reasoned process for arriving at the limit they hold.

ARB says

The Architects Code expects architects to be able to show how they have decided what insurance to put in place. A file note, an annual broker review, a board minute recording the decision, or a written renewal recommendation from a broker are all forms of evidence ARB will accept. An absence of any record is itself a problem.

2.3 The ARB Investigations Committee approach

Complaints engaging Standard 8 are screened by ARB's Investigations Committee. The Committee can dismiss, refer to the PCC, or close with advice. In our experience advising practices through this process, three patterns recur:

1. No PI at the time of the work. This is treated as a serious matter and almost invariably referred to the PCC. The Committee is unimpressed by retrospective top-ups.
2. PI in place but unsuitable. For example, a sole practitioner who held a £250,000 limit while running a £4m residential refurbishment. The Committee will consider proportionality, but a clear mismatch between scope and limit attracts referral.
3. Run-off failures. Retired architects who allowed run-off to lapse before the statutory limitation window had expired. These are the most common cases and the easiest to avoid (see Chapter 16).

2.4 Standard 8 and the practice entity

Standard 8 attaches to the architect personally. If the practice's limited company holds PI but the architect cannot evidence that the cover responds to claims against them personally — including post-dissolution — there is a Standard 8 risk. Practices structured as LLPs, limited companies or partnerships should make sure the policy schedule names the entity, all predecessor entities, all subsidiaries undertaking architectural services, and any individual architect who could be sued in their own name.

Watch out

When a limited company is dissolved or struck off, the company's PI does not "transfer" to the individual. Where you have run a company that has ceased trading, you must arrange entity run-off in the company's name even if you carry on practising elsewhere. ARB has censured architects who assumed their new employer's policy retroactively covered work done in a dissolved company.

Key takeaways — Chapter 2

• Standard 8 is a statutory-style obligation, not best-practice guidance.
• "Adequate and appropriate" is judged on evidence of a reasoned decision, not on a fixed limit.
• ARB's Investigations Committee treats no-cover, mismatched-cover and lapsed run-off as the three common failure modes.
• Cover must follow the architect across all vehicles, including dissolved entities.

Related guides: ARB Minimum Terms PI Explained — Architects PI on Practice Merger or Sale — Architects PI FAQ.

3. ARB minimum PI requirements and the renewal declaration

3.1 The published minimum levels

ARB publishes minimum PI levels for registered architects in its Insurance Guidance. As at the May 2026 review of this guide, the published minimum amounts of cover are tiered by the architect's turnover from architectural services in the preceding year. The current published levels follow the structure set out below; readers should verify the live figures on the ARB website at the time of their renewal as the Board reviews them periodically.

Annual turnover from architectural services	Published minimum limit of indemnity
Up to £100,000	£250,000 each and every claim
£100,001 to £200,000	£500,000 each and every claim
£200,001 to £500,000	£1,000,000 each and every claim
Above £500,000	Limit "appropriate" to the work undertaken

Above the top band, ARB does not publish a single number. Instead it expects the architect to apply the "adequate and appropriate" test from Standard 8 (see Chapter 2). In practice, most practices with turnover above £500,000 hold £1m to £10m on an each-and-every-claim basis, with the choice driven by project value, contractual demands and aggregation risk rather than turnover.

Watch out

The published minima are floors, not ceilings, and they have not been re-priced for inflation in line with construction costs. Treating the minimum as the right answer is precisely the failure mode ARB targets at PCC.

3.2 The aggregation point in ARB minima

The ARB minimum levels are stated on an "each and every claim" basis. That is significant. It means the published minimum is not an aggregate cap — each separate claim should attract the full limit, subject to the policy wording. Where a policy is written on an aggregate basis with separate "costs in addition" or "costs inclusive" treatment, the architect must check that the aggregate limit at the inception of the policy year is at least the ARB minimum, and that there is no risk of erosion below the minimum by mid-year claim spend. We return to this in Chapter 13.

3.3 The renewal declaration

At annual registration renewal (the "retention of registration" fee), ARB requires architects to confirm that they hold insurance in line with Standard 8 and the published minima, or to explain why they do not (for example, an architect not in private practice). This declaration is binding. False or careless declarations can themselves found PCC proceedings under Standard 9 (truthfulness) as well as Standard 8.

ARB also operates a sampled audit. Architects who are sampled must produce evidence of cover, typically the current schedule and certificate. The audit can request retrospective evidence — for example, certificates for the past five years — where there is a reason to do so.

3.4 Employed architects, retired architects and architects on parental or career break

The Code recognises that not every registered architect is in private practice. Architects who are:

• Employed by an employer (including an architectural practice they do not own) and not undertaking any private architectural work outside the employment relationship — generally relying on the employer's policy is acceptable, provided the policy in fact covers them. The architect should obtain written confirmation each renewal that they are an insured under the employer's policy.
• Employed in non-architectural roles — typically academic, civil service or industry. Cover may not be required if no architectural services are being provided to third parties, but the architect must declare the position accurately at renewal.
• Retired or on a long break — see Chapter 16 on run-off.
• In overseas practice — the architect must still satisfy Standard 8 in respect of any UK work and any work where UK law applies. We treat overseas exposure in Chapter 15.

ARB says

An architect who undertakes "favours" — drawings for a friend's extension, a quick scheme for a family member — outside their employer's policy is providing architectural services for the purposes of Standard 8. ARB has investigated cases where unpaid work, done without PI, led to a complaint when the works failed.

3.5 ARB compliance verification process

If you are audited, ARB will ask for:

1. The current schedule and certificate.
2. Evidence that the policy is with an authorised UK insurer or an EU/EEA equivalent regulated entity.
3. Evidence of any sub-limits, particularly cladding/fire safety, that could reduce cover below the published minimum.
4. Where the entity is not the architect personally, evidence that the architect is a named insured or otherwise covered.
5. For retired or non-practising architects, evidence of run-off where work has been done in the past six years (and longer where statutory limitation extends — see Chapters 6 and 11).

Key takeaways — Chapter 3

• ARB publishes turnover-banded minima; above £500,000 the architect must apply the "adequate and appropriate" test.
• The minima are each-and-every-claim figures; aggregate policies need careful checking against the published floors.
• Renewal declarations are binding; ARB audits a sample of registered architects each year.
• Employed, retired and overseas architects each have specific Standard 8 expectations.

Related guides: ARB Minimum Terms PI Explained — Architects PI Cost Estimator — About Apex.

4. RIBA Chartered Practice criteria and how they interact with ARB

ARB regulates individual architects. RIBA accredits practices that meet its Chartered Practice criteria. The two regimes are different in legal status — ARB is statutory, RIBA is a membership body — but they overlap on insurance.

4.1 The Chartered Practice insurance requirement

To be a RIBA Chartered Practice, a practice must hold PI cover with a UK FCA-authorised insurer (or equivalent) at a level appropriate to its work. RIBA cross-refers to ARB's published minima as the floor, then expects the practice to scale upward in line with project value, the use of design-and-build novation, the involvement of any Higher-Risk Building work, and the level of contractual indemnities accepted.

Chartered Practices also commit to RIBA's Code of Professional Conduct, which (like the ARB Code) treats insurance as a professional obligation rather than a commercial choice, and to the Chartered Practice complaints-handling procedure, under which clients can escalate issues to RIBA.

4.2 Quality management and risk management

The Chartered Practice criteria require an employment policy, an equal opportunities policy, a sustainable architectural design policy, an environmental management policy, a quality management policy and a CPD policy. Insurance is one strand of this — risk management documentation (project risk registers, design responsibility matrices, sign-off processes) is read by underwriters at renewal and increasingly affects the rating decision.

4.3 Where ARB and RIBA disagree on emphasis

ARB focuses on the individual architect's responsibility. RIBA focuses on the practice as an entity. The result for insurance is:

• A sole-trader Chartered Practice must hold cover in the trading name and be sure the named individual is insured personally.
• An LLP or company Chartered Practice must hold cover in the entity name, name all subsidiaries, and ensure the architects within it are insured persons under the policy.
• A multi-disciplinary practice (architects plus engineers plus planners) must have a policy that responds to all professional services offered, not just architecture. ARB only cares about the architectural services; RIBA cares about the whole practice and the public-facing brand.

Key takeaways — Chapter 4

• RIBA Chartered Practice status requires PI from an FCA-authorised insurer at a level above the ARB floor.
• The RIBA regime focuses on the practice; ARB focuses on the individual.
• Multi-disciplinary practices must have a policy that responds to all services they hold out to provide.

Related guides: Architects PI overview — Collateral Warranties — Architects.

5. Selecting a limit — fee-band sliding scale and project-value approach

Beyond the ARB minimum, the practical question is "what limit do we actually need?" There is no single correct answer. There is, however, an industry methodology that we recommend practices document at every renewal.

5.1 The three-axis test

Three axes drive the limit decision:

1. Largest single project value. As a rough industry guide, many brokers and insurers expect the limit of indemnity to equal at least 10–25% of the largest project value the practice is involved in, depending on the architect's role and the nature of the project. For a £20m residential block, that suggests a limit of £2m to £5m on a project-value test alone.
2. Aggregate fee income. Where claims aggregate across many smaller projects (for example, a repeated detail flaw across a portfolio), the limit must reflect the cumulative exposure. A practice billing £2m a year on small-residential work has more cumulative-aggregate exposure than a practice with a single large project.
3. Contractual obligations. Some appointments and warranties require specific minimum limits. Public sector frameworks, developer appointments and funder requirements routinely specify £5m or £10m as the floor.

5.2 Indicative limit by turnover and project profile

The table below sets out a typical industry guidance approach. Treat it as a starting point for discussion, not a recommendation.

Turnover from architectural services	Typical largest project value	Indicative limit (private practice, mixed work, no HRB)	Indicative limit (residential/HRB exposure)
Up to £100k	Up to £1m	£250k to £500k	£1m to £2m
£100k to £250k	Up to £3m	£500k to £1m	£1m to £5m
£250k to £500k	£3m to £10m	£1m to £2m	£2m to £10m
£500k to £1m	£5m to £20m	£2m to £5m	£5m to £10m
£1m to £5m	£20m to £100m	£5m to £10m	£10m+ (often layered)
Above £5m	£50m+	£10m+	£10m to £25m+ (layered)

Worked example

A practice with £350,000 fee income, no HRB work, and a largest project value of £4m residential refurbishment. Under the ARB minima, the floor is £1m each and every claim. On the project-value test (10–25%), the indicative limit is £400,000 to £1m. On the contractual test, if any of the appointments require £2m, then £2m is the floor. The reasoned answer is £1m to £2m, depending on appetite for cost-of-claim exposure, with the practice's renewal note recording why.

5.3 Each-and-every-claim vs aggregate

For most UK architects, an each-and-every-claim basis is preferable to aggregate. Each-and-every means the limit refreshes for each new claim within the policy year. Aggregate means the limit is the maximum the insurer will pay across all claims in the year, no matter how many. ARB minima are stated each-and-every. Where the market only offers an aggregate basis (typical for some HRB-exposed practices in the hardened market), the insured should ensure the aggregate is at least equal to the limit they would otherwise have purchased on an each-and-every basis, with a clear understanding of erosion risk.

5.4 Costs in addition vs costs inclusive

UK PI policies typically come in two cost structures: "costs in addition" (defence costs are paid in addition to the limit) and "costs inclusive" (defence costs erode the limit). ARB does not prescribe one or the other, but a costs-inclusive policy with a £1m limit and £400,000 of defence costs leaves only £600,000 to pay damages. For complex construction disputes, defence costs of 20–40% of the limit are not unusual.

Watch out

Costs inclusive is more common in hardened markets and on HRB-exposed business. If you cannot get costs in addition, increase the limit to compensate, and disclose the structure to clients in appointments where they have asked about your cover.

5.5 Excess levels

Excess levels in architect PI typically range from £2,500 for sole practitioners and small studios to £25,000+ for larger practices. Higher voluntary excesses can reduce premium; they also mean the practice carries the first slice of any claim, including the cost of dealing with an investigation that does not result in a payable claim.

Key takeaways — Chapter 5

• Use a three-axis test: largest project value, aggregate fee income, contractual obligations.
• Document the decision at every renewal — this is the evidence ARB will look for.
• Prefer each-and-every-claim and costs-in-addition where the market allows.

Related guides: Architects PI Cost Estimator — Design-and-Build Architects PI Risk.

6. Building Safety Act 2022 — section 135 and the 30-year retroactive limitation

We now turn to what is by far the most disruptive single change in UK architect PI for a generation: the Building Safety Act 2022 ("BSA 2022"). Three sections matter: section 135 (limitation), section 130 (Building Liability Orders) and section 124 (Remediation Contribution Orders). We treat them in three separate chapters.

6.1 What section 135 actually does

Section 135 of the BSA 2022 amends section 1 of the Defective Premises Act 1972 ("DPA 1972 s.1"), which gives a right of action to a person who acquires a dwelling for failure of the workmanship and materials to be such that the dwelling is "fit for habitation". Before the BSA, the limitation period under DPA 1972 s.1 was six years from completion under section 1(5).

Section 135 of the BSA replaces that with two limitation regimes:

• Retroactive — 30 years. For DPA 1972 s.1 claims relating to dwellings completed before 28 June 2022 (the commencement date), the limitation period is 30 years from completion. This applies to dwellings completed any time on or after 28 June 1992.
• Prospective — 15 years. For DPA 1972 s.1 claims relating to dwellings completed on or after 28 June 2022, the limitation period is 15 years from completion.

There is a "human rights override" mechanism in section 135(5) — the court may disapply the retroactive 30-year period where to apply it would breach the defendant's Convention rights, but this is intended as a narrow safeguard, not a routine escape. Early case law (URS v BDW, Hippersley, etc.) has read the retroactive extension as a substantive legislative choice that the courts must apply.

6.2 What this means in practice for an architect

If you designed a dwelling that completed on or after 28 June 1992, and the design fell short of the DPA 1972 s.1 "fit for habitation" standard, a claim under DPA 1972 s.1 can be brought against you until 30 years after the original completion. That is a step-change in tail risk. For a 1995 scheme that completed in 1997, the limitation window now closes in 2027 rather than 2003.

BSA spotlight

Section 135 does not change the limitation period under contract or under tort. It changes the limitation period for DPA 1972 s.1, which is a statutory cause of action that runs alongside contract and tort. So a claimant who is out of time in contract (six years on a simple contract; twelve years on a deed) and out of time in tort (six years from damage; or three from knowledge with a long-stop under the Latent Damage Act 1986) may still be in time under DPA 1972 s.1.

6.3 Section 2A — the BSA-inserted refurbishment duty

Section 135 also inserts a new section 2A into the DPA 1972. We treat section 2A in detail in Chapter 11 because it has its own scope and its own evidential challenges. In short, section 2A extends the DPA "fit for habitation" duty to refurbishment work on existing dwellings — a category not covered by the original 1972 Act, which was limited to "the provision" of a dwelling. The 2A duty applies prospectively only (15 years from completion of the works), but it captures the very work that has driven the post-Grenfell claims wave: external wall refurbishment, balcony works, fire-stopping retrofit, internal compartmentation reworking.

6.4 PI cover and the 30-year tail

Standard UK architect PI is written on a claims-made basis. That means the policy in force at the time the claim is notified responds, not the policy in force at the time of the work. As long as the architect maintains continuous cover, the 30-year retroactive limitation period under section 135 is matched, in principle, by the current year's policy responding to a notification made today on a 1995 scheme.

The hard practical question is what happens when the architect retires, sells the practice, or lets the policy lapse. We cover this in Chapter 16. But the short answer is: run-off of 30 years is now the only safe assumption for dwellings completed on or after 28 June 1992, and 15 years for dwellings completed on or after 28 June 2022.

Worked example

An architect retired in 2018 having designed a residential block completed in 2003. Under the pre-BSA regime, DPA 1972 limitation expired in 2009. The architect took six years of run-off and lapsed it in 2024. Under section 135, the new limitation date is 2033. A claim notified in 2027 against the architect would, on these facts, find no insurance in place. ARB and the courts both treat that as the architect's problem.

6.5 Section 135 and prior-acts cover

For new placements with a new insurer, "prior acts" cover (the retroactive date the insurer is willing to accept) is the critical wording. Insurers may attempt to set a retroactive date that excludes pre-2022 work. ARB does not prohibit this, but a policy that excludes pre-2022 acts is not "adequate" for an architect who has done pre-2022 dwelling work.

Key takeaways — Chapter 6

• Section 135 extends DPA 1972 s.1 limitation to 30 years retroactively (for completions on or after 28 June 1992) and 15 years prospectively.
• Section 2A inserts a new statutory duty for refurbishment work on dwellings, prospective only.
• Claims-made PI responds at notification, not at the time of work — so continuous cover is critical.
• Run-off planning must now contemplate a 30-year window, not the pre-BSA six.

Related guides: Building Safety Act PI — Defective Premises Act PI — Architects BSA Checklist.

7. Building Safety Act 2022 — section 130 Building Liability Orders

7.1 What a Building Liability Order is

Section 130 of the BSA 2022 gives the High Court the power to make a "Building Liability Order" ("BLO"). A BLO is a court order that extends a liability owed by one body corporate to one or more "associated" bodies corporate, making them jointly and severally liable for the same obligation.

For example: if a special-purpose vehicle ("SPV") developer is found liable to leaseholders for fire safety remediation under DPA 1972 or the Building Safety Act, and that SPV is undercapitalised or has been wound up, a BLO can extend that liability to the parent company, sister companies, or any associated body corporate. The court can then enforce against the wider corporate group.

7.2 Why this matters for architects

Architects are predominantly LLPs or limited companies. Many practices are part of wider corporate structures: a group holding company, a separate trading company, a consultancy arm, a Republic of Ireland subsidiary. Section 130 means that liabilities incurred by one entity can be extended to all "associated" entities.

The "associated" definition in section 131 is broad. It picks up:

• Parent and subsidiary undertakings.
• Bodies under common control.
• Bodies where one controls the other.

The court has discretion to make the order where it is "just and equitable" — the threshold for a BLO is not high in practice, and the early case law (BDW v URS; the Triathlon Homes proceedings) has confirmed a willingness to grant orders where corporate structures have been used to defeat liability.

7.3 The PI implications

Three implications follow:

1. All group entities should be named insureds. If only the trading practice is named on the PI schedule, but a BLO extends a liability to the holding company, the holding company has uninsured exposure.
2. Acquisitions and disposals trigger BLO risk. A practice that acquires another may, through corporate association, become exposed to that practice's historic liabilities. The acquiring entity should ensure its PI policy has been notified of the acquisition and that historic exposures are covered (typically through assumption of the seller's run-off or a fresh prior-acts position).
3. Group restructures must be checked. Moving assets out of an associated entity after liability has crystallised is unlikely to defeat a BLO; insurers will increasingly ask about group structure and any restructure activity at renewal.

BSA spotlight

The original draft of the BSA did not include BLOs. They were added during Parliamentary passage in response to evidence that developers had used SPVs to walk away from defective buildings. The legislative intent is plainly remedial, and the courts have so far given the section a purposive reading.

7.4 What the court considers

When deciding whether to make a BLO, the court will consider:

• The relationship between the bodies corporate (degree and nature of association).
• The conduct of the bodies in relation to the building safety risk.
• The capacity of the original defendant to meet the liability.
• Any prejudice to the associated body if the order is made.

Architects acting as expert witnesses or design experts on BLO applications report that the courts treat undercapitalised defendants and post-event group restructures as material factors.

Watch out

A BLO is not a piercing of the corporate veil in the common law sense. It is a statutory power that does not require fraud or sham. The corporate separateness defences that worked under Salomon v A Salomon & Co Ltd do not work under section 130. This is a fundamental change.

7.5 What to do at renewal

We recommend practices undertake an annual BLO mapping exercise:

1. List all bodies corporate that could be "associated" with the practice.
2. For each, confirm whether they are named insureds under the PI policy.
3. For each, confirm whether they have undertaken any building-safety-relevant activity in the past 30 years.
4. Disclose the mapping to underwriters at renewal.

Key takeaways — Chapter 7

• Section 130 lets the court extend building-safety liability across associated bodies corporate.
• The "associated" test is broad and not limited to formal subsidiaries.
• All group entities should be named insureds; acquisitions and restructures need PI scrutiny.
• Corporate separateness defences are limited; structure-based risk transfer is no longer effective.

Related guides: Building Safety Act PI — Architects PI on Practice Merger or Sale.

8. Building Safety Act 2022 — section 124 Remediation Contribution Orders

8.1 What a Remediation Contribution Order is

Section 124 of the BSA 2022 gives the First-tier Tribunal (Property Chamber) — not the High Court — the power to make a "Remediation Contribution Order" ("RCO"). An RCO requires a "specified body corporate or partnership" to make payments for the purpose of meeting costs incurred or to be incurred in remedying "relevant defects" in a "relevant building".

The key definitions:

• "Relevant building" — a self-contained building (or part) containing at least two dwellings and at least 11 metres high or 5 storeys (the same threshold as the leaseholder protection regime in Schedule 8 of the BSA).
• "Relevant defect" — a defect arising from works done in the past 30 years that causes a building safety risk.
• "Specified body corporate or partnership" — the developer, the landlord at the qualifying time, a person associated with either, or a person who was, at the time of the works, the developer or landlord.

8.2 Why architects need to understand RCOs

On a literal reading, the architect is not within the "specified" categories — the section targets developers and landlords, not consultants. But three points complicate that picture:

1. Associated persons. If the architect is corporately associated with the developer or landlord (for example, a developer that has an in-house architectural arm, or a contractor-developer with a captive design team), the architect entity can be brought within the order.
2. Onward recovery. A developer subject to an RCO will look to recover from the consultants whose negligence caused the defect. That is a conventional DPA 1972 / contract / tort claim, with the BSA-extended limitation periods (see Chapter 6).
3. Leaseholder protection regime. Schedule 8 of the BSA prevents qualifying leaseholders from being required to pay for certain remediation costs (cladding remediation in particular). That cost burden must fall somewhere, and the legislative scheme is designed to push it to the developer first, then up the chain to consultants and contractors where the developer has a claim.

8.3 The leaseholder protection regime in summary

Schedule 8 of the BSA introduces statutory protections for "qualifying leaseholders" in "relevant buildings" against being charged for:

• Cladding remediation (all qualifying leaseholders, regardless of net worth).
• Other relevant defects (subject to a cap based on property value, with full protection for leaseholders below a property value threshold and for the landlord-developer where the landlord is or is associated with the original developer).

The cap, the property value bands and the carve-outs are detailed and have been subject to MHCLG amendments since commencement. The effect is to remove the leaseholder as a paying party in most cladding cases, and to push the cost upstream.

8.4 The 30-year retrospective scope

Section 124 RCOs can be made in respect of works done in the previous 30 years. This is the same effective look-back as section 135 (for completions on or after 28 June 1992). Practices that designed residential blocks any time after June 1992 are in scope of an RCO chain, whether as an associated person or as the target of a developer's onward claim.

8.5 PI cover and RCO exposure

PI covers liability "in respect of the civil liability of the insured for any claim". An RCO is a statutory order, not a conventional civil claim — but the conventional claim against the architect arising from the same defects falls squarely within PI. Insurers have responded by:

• Inserting Building Safety Act / cladding / fire safety sub-limits and exclusions.
• Treating BSA-related notifications with higher reserve and scrutiny.
• In some cases, declining to renew where HRB exposure is high.

Watch out

Some 2024–2026 PI policies include a "Building Liability Order" extension or carve-out. Read it carefully. An extension that pays for the cost of defending a BLO application is useful; an exclusion that strips cover for any BSA-derived liability is materially limiting.

Key takeaways — Chapter 8

• RCOs target developers and landlords primarily, but reach architects through "associated person" and through onward recovery claims.
• Schedule 8 leaseholder protection drives cost up the chain.
• PI cover for the underlying negligence claim usually responds; BSA-specific extensions and exclusions vary widely.

Related guides: Building Safety Act PI — Architects BSA Checklist.

9. The Higher-Risk Building regime and Gateways 1, 2 and 3

9.1 What an HRB is

A "Higher-Risk Building" ("HRB") is defined in the BSA 2022 and the Higher-Risk Buildings (Descriptions and Supplementary Provisions) Regulations 2023 as a building of at least 18 metres in height or at least 7 storeys, containing at least two residential units. Care homes and hospitals of the same scale are HRBs during the design and construction phase but fall outside the in-occupation regime. The threshold is the same for both the design/construction regime and the in-occupation regime under the BSA.

9.2 The Building Safety Regulator

The Health and Safety Executive hosts the Building Safety Regulator ("BSR"), which is the building control authority for HRBs and the regulator of the Principal Designer / Principal Contractor regime under the Building Regulations 2010 Part 2A. The BSR has wide powers: it can refuse approval at the Gateways, prosecute for breach of building regulations, impose compliance notices, and remove a building from the BSR register where the safety case is inadequate.

9.3 The three Gateways

The HRB design-and-construction regime is structured around three Gateways:

• Gateway 1 — planning. Building safety considerations must be addressed at planning stage. A fire statement is required for relevant developments. The local planning authority consults the BSR (or, in some routes, the fire and rescue service) on building safety matters.
• Gateway 2 — building control approval before construction. Before construction of an HRB starts, the BSR must approve the design. A full set of drawings, specifications, the construction control plan, the change control plan, the competence declarations of the Principal Designer and Principal Contractor, and the building regulations compliance statement must be submitted. The BSR has 12 weeks (extendable) to determine the application.
• Gateway 3 — completion certification before occupation. Before an HRB can be occupied, the BSR must issue a completion certificate. The application requires the as-built drawings, the building regulations compliance statement reflecting any changes, the safety case report, and dutyholder competence declarations.

9.4 Why architects should care, even for non-HRB work

Many of the procedural requirements that apply at Gateways for HRBs (competence declarations, change control, design responsibility documentation) reflect the wider Part 2A duties that apply to all building work in scope of the Building Regulations — not just HRBs. The Principal Designer regime under regulation 11A to 11J of the Building Regulations 2010 (as inserted by the 2023 amendment regulations) applies to all building work where there is more than one contractor, irrespective of HRB status. We treat this in Chapter 10.

9.5 Insurance implications of HRB work

Underwriters treat HRB work as a distinct category. Practices doing HRB design — whether as lead architect, sub-consultant, or novated designer — should expect:

• Specific underwriting questions about HRB scope at renewal.
• Possible sub-limits or aggregate caps on HRB-related claims.
• Higher excess on HRB notifications.
• In some markets, an outright HRB exclusion (which then puts the practice on the wrong side of Standard 8 if HRB work is taking place).

Watch out

Be precise about the practice's HRB role in renewal disclosures. A practice that was lead architect on a non-HRB scheme but became Principal Designer on an HRB after a novation should disclose both roles. Misdescription at renewal can vitiate cover under the Insurance Act 2015 fair-presentation duty.

Key takeaways — Chapter 9

• HRB = 18m / 7 storeys / 2+ residential units (or care home/hospital at construction).
• The BSR is the regulator and building control authority for HRBs.
• Three Gateways structure the design-construction-occupation timeline.
• PI underwriters treat HRB exposure as a distinct rating factor.

Related guides: Principal Designer BSA — Building Safety Act PI.

10. The Principal Designer role under Building Regulations Part 2A

10.1 Two Principal Designer regimes

A persistent source of confusion is that there are now two Principal Designer regimes in UK construction:

• CDM Principal Designer — under the Construction (Design and Management) Regulations 2015, regulated for health and safety during construction.
• BR Principal Designer — under Part 2A of the Building Regulations 2010, regulated for compliance of design with the Building Regulations.

They are distinct roles, with distinct dutyholder duties, distinct competence requirements, and distinct PI implications. An architect can hold one, both or neither on any given project. In practice on HRBs, the same individual or practice often holds both, but the duties remain separate.

10.2 The BR Principal Designer duty

The BR Principal Designer (sometimes called "Principal Designer under the Building Regulations" to distinguish it) is appointed by the client where there is more than one contractor. The role's headline duty is to plan, manage and monitor the design work during the design phase so that the design, when carried out, will be in compliance with all relevant requirements of the Building Regulations.

Specific duties under regulation 11D to 11J include:

• Ensuring designers comply with their individual duties under regulation 11C.
• Co-ordinating matters relating to the design work.
• Providing the dutyholder client with the information necessary to comply with the client's duties.
• For HRBs, signing the dutyholder competence declarations submitted at Gateways.

10.3 Regulation 11D — competence

Regulation 11D requires that the Principal Designer (whether an individual or an organisation) has "the skills, knowledge, experience and behaviours" to fulfil the role. The Department for Levelling Up published competence guidance, and the British Standards Institution issued BSI Flex 8670 (a baseline competence standard for individuals working on the built environment) and PAS 8671 (specifically for Principal Designers under the Building Regulations).

PAS 8671 sets out the competencies required and the assessment routes. An architect taking on the BR Principal Designer role should be able to evidence:

• Knowledge of all parts of the Building Regulations relevant to the project.
• Knowledge of approved documents and equivalent standards.
• Project management skills appropriate to the project scale.
• Behavioural competencies (challenging, communicating, recording).

BSA spotlight

The Building Safety Regulator can challenge competence at Gateway. If the BSR is not satisfied that the Principal Designer is competent, Gateway 2 approval can be refused, blocking construction entirely. There is no current PI market for "BSR refused our PD" — this is a reputational and commercial risk, not an insurable one.

10.4 PI implications of the BR Principal Designer role

Holding the BR PD role increases an architect's exposure in three ways:

1. Scope of duty. The PD's duty extends beyond their own design work to the design work of all other designers on the project. A flaw in the structural engineer's fire-engineering approach can land on the PD if the PD failed to co-ordinate or to challenge.
2. Statutory standing. The PD is named in the Building Regulations and in the Gateway documentation. They are easy to identify as a defendant.
3. Evidence trail. The PD must keep records; those records are disclosable in litigation. Both good and bad records work harder in court than oral recollection.

10.5 Disclosure at PI renewal

Insurers now ask, as a discrete renewal question, whether the practice is acting as BR Principal Designer on any current project. A "no" answer that turns out to be wrong is grounds for the insurer to argue breach of the fair-presentation duty under the Insurance Act 2015.

Worked example

A practice signs a deed of appointment naming the architect as "Principal Designer". The renewal form asks if the practice is acting as Principal Designer. The architect ticks "yes" on the assumption that the question relates to CDM. In fact the appointment is for both CDM PD and BR PD, and the project is an HRB. At a later claim, the insurer argues misrepresentation. The fix is to ask which regime, on which project, and to record both in the renewal disclosure.

Key takeaways — Chapter 10

• CDM PD and BR PD are distinct roles with distinct duties and PI implications.
• The BR PD duty under Part 2A is broader than CDM and extends across the whole design team.
• Competence is regulated under reg 11D, with PAS 8671 setting the baseline.
• PI renewal disclosure must distinguish both PD roles, project by project.

Related guides: Principal Designer BSA — Architects BSA Checklist.

11. Defective Premises Act 1972 — sections 1 and 2A in the BSA era

11.1 The DPA 1972 in its original form

The Defective Premises Act 1972 created a statutory duty owed by anyone "taking on work" for or in connection with "the provision of a dwelling" to see that the work is done in a workmanlike or professional manner, with proper materials, and so that the dwelling will be "fit for habitation" when completed (section 1).

The duty is owed to the person to whose order the dwelling is provided and to every person who acquires an interest in the dwelling. Limitation was originally six years from completion (section 1(5)).

11.2 What section 135 BSA changed

As described in Chapter 6, section 135 BSA changed the limitation period to 30 years retroactively (for completions on or after 28 June 1992) and 15 years prospectively (for completions on or after 28 June 2022).

It also inserted a new section 2A. Section 2A extends the DPA duty to a person who, in the course of a business, takes on work in relation to any part of a building containing one or more dwellings, where the work is not "the provision of a dwelling" (i.e. is refurbishment, refitting, or other work that does not create a new dwelling). The duty is to see that the work is done so that the dwelling, after the work, is fit for habitation.

11.3 Why section 2A matters

The original DPA 1972 has been criticised for decades as having a narrow scope: it applied only to "the provision of a dwelling", which the courts interpreted as the creation of a new dwelling, not refurbishment of an existing one (Jenson v Faux confirmed this on appeal). That meant that the very work most often involved in post-Grenfell defects — recladding, refurbishment, refitting, balcony upgrades, fire-stopping retrofit — was outside the DPA.

Section 2A reverses that. From 28 June 2022, any business that takes on work to a building containing dwellings owes the DPA-style "fit for habitation" duty, and the limitation period is 15 years from completion.

11.4 Practical scope of section 2A

Three points to note:

1. Prospective only. Section 2A does not apply to refurbishment works completed before 28 June 2022. Those works are subject to the pre-BSA limitation regime (contract, tort, and potentially the much narrower original DPA 1972 if "provision" rather than refurbishment).
2. "Business" requirement. Section 2A applies to work done "in the course of a business". An architect operating as a registered practice clearly meets this; an architect doing a one-off favour without invoice probably does not (though they may still owe contract/tort duties).
3. "Fit for habitation" is a high standard. Case law on the original DPA shows that the courts will treat fire safety, structural safety, dampness penetration and habitability problems as engaging the duty. Cosmetic defects, by contrast, will not.

11.5 PI implications

Section 2A is a new statutory cause of action with a 15-year limitation tail. Architects doing refurbishment work on existing residential blocks (the most common type of HRB-adjacent work) now have a 15-year exposure window under a statutory duty that did not exist before mid-2022.

PI policies should respond to section 2A claims on the same basis as section 1 claims, provided the policy is in force at the time of notification and the work falls within the policy's scope and retroactive date.

Watch out

Refurbishment-heavy practices should map their post-June 2022 project list against section 2A. Each project is a 15-year liability. A practice doing 40 refurbishment projects a year is accumulating 40 new 15-year tail exposures annually.

Key takeaways — Chapter 11

• DPA 1972 s.1: 30 years retroactive, 15 years prospective, for "provision of a dwelling".
• DPA 1972 s.2A: 15 years prospective only, for refurbishment of buildings containing dwellings.
• Section 2A is BSA-inserted and captures the post-Grenfell refurbishment claims wave.
• PI must respond on a claims-made basis with appropriate retroactive cover and continuous renewal.

Related guides: Defective Premises Act PI — Building Safety Act PI.

12. RIBA Standard Form Collateral Warranty 2020 and net contribution

12.1 Why collateral warranties exist

A collateral warranty is a contract that runs from a consultant (or contractor) to a third party (typically a funder, tenant, purchaser or — increasingly — leaseholder representative body) creating direct contractual rights in respect of the consultant's services. Without a collateral warranty, the third party has no contract with the consultant and must rely on the much harder route of tort and DPA claims.

Collateral warranties have proliferated post-Grenfell because the leaseholder protection regime in Schedule 8 of the BSA, combined with section 124 RCOs, has incentivised every party in the contractual chain to obtain enforceable rights against the consultants.

12.2 The RIBA Standard Form CW 2020

The RIBA Standard Form Collateral Warranty (2020 edition, with the May 2024 supplement on BSA matters) is the most widely used architect collateral warranty in the UK. Its key features:

• Limitation matched to underlying appointment — the warranty has the same limitation period as the architect's appointment, typically 12 years from completion if executed as a deed.
• No fitness for purpose — the standard form does not impose a fitness for purpose obligation; the architect's duty is to exercise reasonable skill and care.
• Net contribution clause — the architect's liability is limited to the share that it would be just and equitable for the architect to pay, having regard to the responsibility of other parties whose acts or omissions contributed to the loss.
• No greater duties than to original client — the consultant's duties to the beneficiary are no greater than those owed to the original client.
• Restriction on assignment — typically limited to two assignments without consent.

12.3 Deviations from the standard form

In practice, employers, developers and funders routinely propose amendments that increase the architect's exposure:

Standard form position	Common amendment	PI implication
Reasonable skill and care	Fitness for purpose / specific design warranty	Almost certainly excluded by PI policy — uninsured exposure
Net contribution clause	Net contribution deleted	Joint and several liability — architect picks up insolvent co-defendants' shares
No greater duties	Specific additional duties	New uninsured duties if not within "professional services" scope
12-year limitation	12 years plus DPA/BSA carve-out	Acceptable, but architect must understand the 30-year statutory route runs alongside
Two assignments	Unlimited assignments	Increases litigation risk; usually acceptable if otherwise standard
No fitness	Compliance with Building Regulations as an absolute duty	Strict liability — uninsured

Worked example

A developer amends the CW to require the architect to warrant that the design "complies with the Building Regulations and all relevant statutory requirements". This is a strict-liability warranty. Reasonable skill and care does not get the architect home if the regulations are in fact breached. The architect's PI policy excludes strict-liability obligations beyond reasonable skill and care. The architect would need to either resist the amendment, qualify the warranty ("subject to the architect's duty of reasonable skill and care"), or accept the exposure as uninsured.

12.4 Net contribution — the case law

Net contribution clauses are enforceable in English law where they are clearly drafted (West v Ian Finlay; Royal Brompton Hospital v Hammond). They are particularly important in cladding/fire safety claims where contractors and material suppliers may be insolvent and the architect would otherwise be exposed to joint and several recovery.

12.5 Third-party rights

The Contracts (Rights of Third Parties) Act 1999 allows benefit to be conferred on third parties without a separate warranty. RIBA's standard appointments include third-party rights provisions that can substitute for collateral warranties. For architects, both routes carry similar PI implications — the substantive duty is the same. The administrative burden of third-party rights is usually lower.

12.6 Number of warranties

A typical residential development might require warranties to:

• The freeholder.
• Each long-leaseholder (or a single warranty to the resident management company).
• The funder.
• The purchaser of any commercial element.
• A future buyer of the development.

This can run to 10 or more warranties per project. Each one is a separate contractual duty owed to a separate party. Each one expands the claimant base in any future dispute.

Key takeaways — Chapter 12

• Use the RIBA Standard Form CW 2020 as the starting point and resist material deviations.
• Net contribution clauses materially reduce architect exposure and should be preserved.
• Fitness-for-purpose, strict-compliance and unlimited-assignment provisions all create uninsured risk.
• Map warranties on each project and disclose at PI renewal.

Related guides: Collateral Warranties — Architects — Design-and-Build Architects PI Risk.

13. Aggregation — single-event vs each-claim, cladding, fire and RAAC

13.1 The aggregation concept

"Aggregation" in PI is the mechanism by which an insurer treats multiple claims as a single claim for limit purposes. Whether aggregation applies depends on the policy wording, the nature of the claims, and the underlying facts.

Aggregation works in two directions:

• In the insured's favour when the excess is per-claim — multiple aggregated claims share one excess, which is cheaper for the insured.
• In the insurer's favour when the limit is per-claim — multiple claims aggregated to one limit means the insured gets only one limit, not many.

In high-volume claims scenarios (cladding, fire safety, RAAC), the second direction predominates.

13.2 Common aggregation wordings

UK PI policies typically use one of the following aggregation triggers:

1. "Originating cause" — claims arising from any one originating cause are treated as a single claim. This is broad and insurer-friendly: a single design decision that affects multiple buildings can aggregate them all into one claim.
2. "Related acts or omissions" — claims arising from related acts or omissions of the insured are aggregated. Narrower than originating cause, but still capable of catching repeated defects.
3. "Single event" — claims arising from a single event are aggregated. Narrowest of the three; usually requires a single discrete incident.
4. No aggregation — each claim is treated separately, with its own limit. Rare in modern UK architect PI for HRB-exposed business.

13.3 Worked aggregation examples

The table below illustrates how each wording works in a cladding-style scenario. Assume the architect designed cladding details to the same specification on 8 different residential blocks for the same developer over a 3-year period.

Wording	Likely aggregation outcome	Effective limit available
Originating cause	Single design decision = one originating cause = one claim	1 x policy limit
Related acts or omissions	All 8 blocks share related design omissions = aggregated	1 x policy limit
Single event	Each block is a separate event of installation/completion = 8 claims	8 x policy limit, subject to aggregate
No aggregation	Each of 8 claims separate	8 x policy limit, subject to aggregate

Worked example — RAAC

A practice designed roof structures using RAAC in 12 school buildings between 1996 and 2003, in line with the then-prevailing engineering advice. In 2024 the schools are surveyed and RAAC removal is ordered. If the practice's current PI policy aggregates by "originating cause" (the design decision to use RAAC), all 12 schools share one limit. On a £5m limit that is £5m total. If the wording is "single event", each school's notification may have its own limit; on a £5m limit that could be up to £60m of cover, subject to the aggregate.

13.4 Cladding aggregation in practice

Insurers commonly include cladding-specific aggregation language in 2024–2026 wordings. Typical drafting aggregates "all claims arising from or attributable to or in connection with the design, specification, installation or remediation of external wall systems" into a single claim. This is aggressively insurer-friendly and converts a portfolio of cladding exposures into a single limit.

Watch out

Read the aggregation clause alongside any cladding sub-limit. A £2m cladding sub-limit with "originating cause" aggregation is a £2m total cap on all cladding work, not a £2m per-claim cap.

13.5 The "claims series" wording

Some markets have introduced "claims series" extensions that treat all related claims as one for excess purposes but as separate claims for limit purposes — the most insured-friendly position. This is rare in standard architect PI and tends to be available only to large practices with strong loss records.

13.6 What to ask at renewal

At every renewal, the practice's broker should be able to answer:

1. What aggregation wording applies to my policy?
2. What aggregation wording applies to any cladding, fire safety or HRB sub-limit?
3. How would each of my top 5 project portfolios aggregate under that wording?
4. What is the worst-case aggregate exposure across my live projects?

If the broker cannot answer these questions, the practice has an insurance information gap that should be closed before renewal.

Key takeaways — Chapter 13

• Aggregation wording determines whether a portfolio of similar projects shares one limit or many.
• "Originating cause" is the broadest and most insurer-friendly trigger.
• Cladding sub-limits combined with originating-cause aggregation create concentrated exposure.
• Document aggregation analysis at every renewal.

Related guides: Ultimate UK PI Guide 2026 — Design-and-Build Architects PI Risk.

14. Design-and-build, novation and contractor-led risk transfer

14.1 The D&B model

In design-and-build ("D&B") procurement, the contractor takes single-point responsibility for both design and construction. The architect typically begins the project under direct appointment by the employer (the "pre-novation" phase) and is then novated to the contractor (the "post-novation" phase). After novation the architect's contract is with the contractor, not the employer.

14.2 The two PI exposures in D&B

D&B creates two distinct PI exposures for the architect:

1. Pre-novation work — the architect's design under the employer's appointment, up to the point of novation. The employer relies on this design when entering the D&B contract.
2. Post-novation work — the architect's continuing design under the contractor's appointment, through to completion.

The novation deed determines how the pre-novation work is treated. The two common forms are:

• "Ab initio" novation — the architect is treated as having been appointed by the contractor from the outset. The contractor is deemed to have the benefit of the pre-novation work.
• "Switch" novation — the original appointment is terminated and a new appointment with the contractor commences from novation. The contractor only has rights for post-novation work.

Most modern D&B novations are ab initio and require the architect to warrant pre-novation work to the contractor.

14.3 The "double duty" problem

Under an ab initio novation, the architect owes duties:

• To the original employer (under collateral warranty, third-party rights, or under the appointment as preserved).
• To the contractor (under the novated appointment).

If the design is later said to be defective, both parties may sue. The architect cannot use one's claim to defeat the other's; both claims must be defended.

14.4 Contractor's risk-transfer demands

Contractors routinely demand:

• Collateral warranties from the architect to the employer, funder, purchaser and tenant.
• Step-in rights in favour of the contractor and the employer.
• Fitness-for-purpose warranties.
• Indemnities for any delay caused by the architect.
• Specific design liability provisions matched to the D&B contract.

Many of these provisions are at the edge of, or outside, standard PI cover. The architect must read each in conjunction with their policy.

14.5 Insurance implications

D&B work attracts a higher PI rating than direct-employer work because:

• The novated architect typically signs contractor-friendly amendments to standard appointments.
• The duties owed multiply (employer + contractor + warranty beneficiaries).
• The risk of being pulled into the contractor's defence of an employer claim is high.
• Disputes about scope of design responsibility are common.

Worked example

A practice is appointed by a developer to RIBA Stages 1–4 on a residential scheme. At Stage 4 the practice is novated to a D&B contractor and continues to Stage 5. The completed building is later found to have cladding defects. The developer sues the contractor. The contractor brings the architect into the claim under the novated appointment, arguing the cladding specification at Stage 4 was negligent. The developer also sues the architect directly under the collateral warranty. The architect now faces two parallel claims arising from the same set of facts. The PI policy responds, but the defence costs are doubled and the aggregation analysis becomes critical.

14.6 What to negotiate

Practice principals doing D&B work should focus on:

1. Limiting fitness-for-purpose obligations to the architect's reasonable skill and care standard.
2. Preserving net contribution clauses in collateral warranties.
3. Capping liability to a stated multiple of fees or a fixed cash figure (subject to public-policy enforceability concerns).
4. Excluding consequential and economic loss to the extent the law allows.
5. Aligning limitation periods in the novation deed with the underlying appointment.

Key takeaways — Chapter 14

• D&B novation creates dual duties to employer and contractor.
• Ab initio novation is the default; switch novation is rare.
• Contractors demand risk-transfer provisions that often exceed standard PI cover.
• D&B practices should pursue contract amendments to keep duties within reasonable skill and care.

Related guides: Design-and-Build Architects PI Risk — Collateral Warranties — Architects.

15. Overseas projects, jurisdiction and US/Canada carve-outs

15.1 Territorial limits

UK PI policies are typically written with one of three territorial limit structures:

• UK only — the policy responds only to claims arising from work done in the UK.
• Worldwide excluding US/Canada — the policy responds anywhere except for claims first brought in the US or Canada.
• Worldwide including US/Canada — full worldwide cover, with a significant premium loading.

For most UK practices, "worldwide excluding US/Canada" is the practical default. Even practices that only work in the UK occasionally find themselves with overseas exposures (a UK client building a Spanish villa; a UK-designed scheme later sold to an overseas buyer who then sues).

15.2 Why US and Canada are excluded

The US legal system carries materially higher litigation cost, broader discovery, jury trial in many states, punitive damages, and contingency-fee claimant funding. Canadian courts share some of these features. The premium loading for full US/Canada cover can be several times the underlying premium.

15.3 Governing law and jurisdiction

A UK appointment can be governed by foreign law if the contract so provides. A UK architect with an appointment governed by Dubai law and subject to DIFC jurisdiction is in a different position from a UK architect with English law and the courts of England and Wales.

Architects working overseas should:

• Identify the governing law of each appointment.
• Identify the jurisdiction (courts or arbitration) of each appointment.
• Check that the PI policy responds in that jurisdiction.
• Check whether the host country has any compulsory local insurance requirement (for example, in some Gulf states a project-specific PI policy with a locally licensed insurer is required).

15.4 Certificate of insurance demands

Overseas clients (and increasingly UK clients on large schemes) often demand a certificate of insurance with specific wording:

• Named project.
• Specific limit.
• Specific retroactive date.
• Confirmation that the policy responds to the named jurisdiction.
• Lloyd's or specific insurer credit rating.

Brokers should be able to produce certificates that meet these demands. Where the policy cannot respond as required, the broker should advise on alternatives — typically a project-specific PI ("project PI") policy that runs alongside the annual practice policy.

15.5 Project-specific PI

Project-specific PI is a dedicated policy for a single project. It has:

• A dedicated limit not shared with the practice's annual policy.
• A bespoke retroactive date, usually matching the project's commencement.
• A run-off period built into the policy (typically 10 to 12 years from completion).
• A premium paid upfront, calculated on the project value.

Project PI is most often used on very large overseas schemes, complex UK residential developments where the contractual demands cannot be met by the practice's annual policy, and joint venture projects with unusual structures.

15.6 The Insurance Act 2015 fair-presentation duty

Overseas work must be disclosed at renewal. The Insurance Act 2015 requires the insured to make a "fair presentation of the risk", which means disclosing every material circumstance the insured knows or ought to know. Overseas project work is invariably material. Non-disclosure can lead to remedies up to and including avoidance of the policy.

Watch out

"Just a small overseas project" is not a safe assumption. A £50,000 fee on a US scheme can trigger US litigation exposure that the standard worldwide-excluding-US/Canada policy will not respond to. Disclose every overseas appointment, every time.

Key takeaways — Chapter 15

• Territorial limit choice is a critical wording issue; worldwide excluding US/Canada is the practical default.
• Foreign-law appointments and foreign-jurisdiction disputes need specific PI scrutiny.
• Project-specific PI is the route where annual PI cannot meet a particular project's needs.
• Insurance Act 2015 fair-presentation duty requires full disclosure of overseas exposure.

Related guides: Ultimate UK PI Guide 2026 — Architects PI overview.

16. Run-off, retirement, mergers and the long tail

16.1 What run-off is

Run-off is PI cover for past work after the practice has ceased trading or the architect has retired. Because PI is claims-made, the policy in force when the claim is notified must respond. After cessation there is no current policy unless run-off is purchased.

16.2 The new run-off horizon under BSA 2022

Before the BSA, run-off of six years was treated as a working default (matching DPA limitation and most contract limitation). After the BSA:

• For dwellings completed on or after 28 June 1992: 30 years from completion under DPA 1972 s.1.
• For dwellings completed on or after 28 June 2022: 15 years from completion under DPA 1972 s.1.
• For refurbishment of dwellings completed on or after 28 June 2022: 15 years from completion under DPA 1972 s.2A.
• For non-dwelling work: 12 years from completion (contract executed as deed) or 6 years (simple contract), plus tort and Latent Damage Act timeframes.

This means a sole practitioner retiring in 2026 who designed dwellings between 1995 and 2025 faces statutory exposure running to as late as 2055.

16.3 Run-off availability

The UK PI market provides annual run-off in most cases. The challenge is:

• Long-term affordability. Run-off premiums typically reduce over the first 3–5 years, then stabilise. Even at the reduced level, run-off on a former HRB-exposed practice can be £10,000–£30,000+ per year.
• Market access. Insurers reserve the right to non-renew run-off. A practice that has had claims in its trading years may struggle to retain a willing insurer after several years of run-off.
• Six-year guaranteed run-off. Some markets offer six-year guaranteed run-off as a paid-up extension on the final trading-year premium. This guarantees cover for six years regardless of subsequent claims, but does not extend to year 7 or beyond.

16.4 Run-off on mergers and acquisitions

When a practice merges with or is acquired by another, the acquirer's PI typically picks up the acquired practice's prior acts — but only if specifically agreed. Common structures:

• Successor practice approach. The acquirer's policy is extended to cover the seller's prior acts. The seller's policy is then lapsed.
• Seller's run-off. The seller buys run-off for, say, 30 years. The acquirer's policy covers only post-acquisition work.
• Hybrid. The acquirer covers acts during the seller's last 6 years; the seller buys run-off for earlier work.

The choice has material implications under BSA section 130 (BLO risk for the acquirer if "associated" with the seller's group) and section 124 (RCO risk if the acquirer is in the chain of "associated persons").

Worked example

A 4-partner practice (Practice A) is acquired by a 20-partner practice (Practice B) in 2026. Practice A has designed several residential blocks since 1995. Practice B's PI policy is extended to cover Practice A's prior acts. Practice A is then dissolved. In 2031, a 1998 Practice A scheme is the subject of a DPA s.1 claim. The claim is notified to Practice B's policy, which responds. Without the prior-acts extension, the claim would have found no insurance in place — Practice A having been dissolved without run-off.

16.5 Retirement of individual partners

Partners or directors retiring from a continuing practice are usually covered by the practice's continuing policy for their past acts. The architect's protection depends on the practice continuing to renew. The retiring partner should:

• Obtain a written confirmation from the continuing practice that they remain an insured person.
• Ask for notification rights if the practice's policy lapses or is materially restricted.
• Consider personal "ex-partner" run-off cover where the practice's continuation cannot be guaranteed.

16.6 Practice insolvency

Where a practice enters insolvency, the Third Parties (Rights against Insurers) Act 2010 gives claimants direct rights against the insurer. PI cover therefore continues to respond to claims arising from the insolvent practice's acts, subject to the policy terms and the run-off / prior-acts position.

Watch out

Insolvency does not erase liability. The architect personally may remain exposed (directly under DPA s.1, or under personal contractual undertakings), and the practice's PI may still respond — but only if it is in force or in run-off. Voluntary strike-off of a company without arranging run-off is a recurring source of uninsured liability.

Key takeaways — Chapter 16

• The BSA has extended the relevant statutory limitation to as much as 30 years; run-off planning must match.
• Run-off is typically arranged annually but with market non-renewal risk; six-year guaranteed extensions are a useful tool.
• On merger or sale, the prior-acts position must be expressly agreed, in writing, in the deal documents.
• Voluntary company strike-off without run-off is a common cause of uninsured exposure.

Related guides: Architects PI on Practice Merger or Sale — Ultimate UK PI Claim Management Guide 2026.

17. Frequently asked questions

Is PI insurance compulsory for UK architects?

Yes. Standard 8 of the ARB Architects Code requires every registered architect to hold "adequate and appropriate" PI cover. ARB publishes turnover-banded minima. PI is a precondition of continued registration on the Register kept under section 3 of the Architects Act 1997.

What is the minimum PI cover for UK architects in 2026?

ARB publishes turnover-banded minima: £250,000 each and every claim for turnover up to £100,000; £500,000 for £100,001 to £200,000; £1,000,000 for £200,001 to £500,000; and "appropriate to the work" above £500,000. The minimum is a floor, not the recommended limit. Always verify the live figure on the ARB website at renewal.

Does BSA 2022 section 135 mean I need 30 years of run-off?

In practice yes, for practices that have designed dwellings completed on or after 28 June 1992. Section 135 extends the DPA 1972 s.1 limitation period to 30 years retroactively for such dwellings. Because PI is claims-made, run-off should match the statutory liability window.

What is the difference between CDM Principal Designer and Building Regulations Principal Designer?

They are distinct roles under separate regimes. The CDM PD (Construction (Design and Management) Regulations 2015) is responsible for managing health and safety during construction. The BR PD (Building Regulations 2010 Part 2A, inserted in 2023) is responsible for compliance of design with the Building Regulations. The same individual may hold both, but the duties are separate.

Can I sign a fitness-for-purpose collateral warranty if my PI policy excludes it?

Strictly, the warranty is enforceable as a contract — but the architect will be exposed to uninsured liability to the extent the policy excludes fitness-for-purpose obligations. The recommended position is to qualify the warranty to reasonable skill and care or refuse the amendment.

What is a Building Liability Order and could it affect my practice?

A BLO under section 130 BSA 2022 is a court order that extends a liability owed by one body corporate to one or more associated bodies corporate. Practices that are part of group structures, that have undertaken acquisitions, or that have related entities, should ensure all "associated" bodies are named insureds and that group-wide PI exposure is mapped.

Does my PI cover Higher-Risk Building work?

It depends on the policy. Many 2024–2026 wordings include HRB-related sub-limits, aggregate caps, or exclusions. HRB exposure must be disclosed at renewal under the Insurance Act 2015. A policy that excludes HRB work would place an architect doing HRB work in breach of Standard 8.

What happens to my PI if I retire?

Run-off cover continues to respond to claims notified after retirement, but only if it is in place. Six years was the historical default. With BSA-extended limitation, run-off of up to 30 years may be needed for dwellings completed since 1992. Run-off is typically arranged annually.

How does aggregation work on cladding claims?

Most modern UK PI policies include broad "originating cause" aggregation that treats multiple cladding claims arising from a common design specification as a single claim subject to one limit. Cladding sub-limits combined with originating-cause aggregation create concentrated exposure that should be modelled at renewal.

Do I need project-specific PI on overseas schemes?

Often yes. Standard worldwide-excluding-US/Canada cover may not respond to a particular jurisdiction's demands, may not meet local compulsory insurance rules, or may not satisfy a client's certificate-of-insurance requirements. Project-specific PI is a dedicated policy with a bespoke retroactive date and built-in run-off.

Am I covered for a Defective Premises Act section 2A claim?

Most claims-made PI policies will respond to a section 2A claim provided the policy is in force at notification, the work falls within the policy's scope, and the retroactive date predates the work. Section 2A applies only to refurbishment work completed on or after 28 June 2022.

What happens if I'm sued under a Building Liability Order?

A BLO is a statutory order extending an existing liability. The underlying liability — for example, negligent design under DPA s.1 — is the conventional civil claim that the PI policy will be asked to cover. The BLO itself is not a separate insurable event; its effect is to expand the universe of paying parties.

Should I take six-year guaranteed run-off or annual run-off?

Six-year guaranteed run-off provides certainty in the early years when claim activity is most likely. Annual run-off is more flexible and lets you adjust the limit and excess as exposure declines, but carries market non-renewal risk. Many practices use a hybrid: guaranteed for the first six years, annual thereafter.

How does ARB audit my PI cover?

ARB operates a sampled audit programme. Selected architects are required to produce evidence of cover — schedule, certificate, and where relevant evidence of run-off. The audit may extend to retrospective years if there is reason to do so.

Where can I get specific advice on my practice's PI?

This guide is a reference. For a specific recommendation on limit, wording, run-off or contract review, contact Apex Insurance Brokers Ltd (FCA FRN 724952). We are an FCA-authorised broker advising UK architectural practices on PI placement, claims handling and contractual review.

18. About Apex Insurance Brokers Ltd

Apex Insurance Brokers Ltd is a Bristol-based UK insurance broker authorised and regulated by the Financial Conduct Authority (FCA FRN 724952) and registered at Companies House (registered number 07014570). We specialise in professional indemnity, commercial combined, management liability and construction-related insurance for UK businesses, including architectural practices of all sizes.

This guide is published as a definitive reference, not as personal recommendation. It does not constitute legal advice. For a specific recommendation on your practice's PI cover, contact us via the Apex contact page or speak to our team.

Author: Apex Insurance Brokers

Last reviewed: May 2026

Disclosures: Apex Insurance Brokers Ltd is authorised and regulated by the Financial Conduct Authority. FCA Firm Reference Number 724952. Registered in England and Wales, Companies House number 07014570. Information given here is general in nature, written for UK architects and architectural practices, and based on the legal and regulatory position as at the May 2026 review date. The Architects Code, ARB published guidance, the Building Safety Act 2022, the Building Regulations and other statutory and regulatory provisions are subject to change; readers should verify the live position before relying on this content. This guide is not personal recommendation under FCA rules. It does not constitute legal advice. Specific transactions, contracts, claims and ARB matters should be referred to qualified legal advisers and to an authorised insurance broker.

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