Principal Designer - architect PI exposure under the BSA

Spoke 3 of the Apex Insurance Brokers Building Safety Act 2022 hub. If you are an architect, a multi-disciplinary lead designer, or a fire-engineering principal, this article is the most operationally important of the eight.

Plain English summary

Since 1 October 2023, every project subject to the Building Regulations in England has needed a Principal Designer as a statutory duty-holder. This is distinct from — and additional to — the Principal Designer role under the CDM Regulations 2015.

The Principal Designer under the Building Regulations 2010 (as amended) is the lead designer for compliance with the Building Regulations during the design phase. Their statutory duties include planning, managing and monitoring the design work, coordinating compliance matters across the design team, and providing information to the Client and the Principal Contractor. On HRB projects, the Principal Designer is also one of the signatories of the Gateway 2 application and must hold the competence to discharge the role.

The duties bring civil liability for breach (under section 38 of the Building Act 1984, as well as section 1 of the Defective Premises Act 1972 in respect of dwellings). They also bring criminal liability under section 35 of the Building Act 1984 as amended by the BSA 2022 — and the maximum penalties were materially increased by the BSA 2022.

For an architect or multi-disciplinary practice, the role is now front-and-centre of underwriter scrutiny. Insurers want to know which of your projects you hold Principal Designer status on, what your competence framework looks like, how you discharge the duty, and what your run-off horizon looks like for projects already in train.

The legal position

The two Principal Designer roles

It is critical to keep two regimes apart in your head:

CDM Principal Designer — under the Construction (Design and Management) Regulations 2015. Concerned with health-and-safety risk through design choices. In force since 2015. Not changed by the BSA 2022.
Building Regulations Principal Designer — under Part 2A of the Building Regulations 2010, inserted by the Building Regulations etc. (Amendment) (England) Regulations 2023 (SI 2023/911). Concerned with compliance with the Building Regulations. In force from 1 October 2023.

The same person can be both, but the duties are distinct, and the appointment letters should distinguish them.

The statutory duties

The Principal Designer's duties under the inserted Part 2A of the Building Regulations 2010 (introduced by SI 2023/911) are set out across several connected regulations. In summary:

Plan, manage and monitor the design work during the design phase.
Coordinate matters relating to the design work to ensure that the design, if built, would comply with all relevant requirements of the Building Regulations.
Cooperate with the Client, the Principal Contractor, and any other person on the project on matters relating to the design.
Provide design information to the Principal Contractor and the Client.
Liaise with the Principal Contractor in respect of any design done by the contractor during the construction phase.

Part 2A also imposes parallel duties on designers generally — every designer must ensure that the design they prepare would comply with the Building Regulations. So even if you are not the Principal Designer, you have a discrete personal duty.

On HRB projects there are additional duties: contributing to the Gateway 2 design and construction control plan, managing change control through the project, contributing to the golden thread, and signing the competence declaration.

The competence requirement

Part 2A of the Building Regulations 2010 (as amended) requires every dutyholder, including the Principal Designer, to have the "skills, knowledge, experience and behaviour" ("SKEB") necessary to fulfil the role on the project in question. PAS 8671:2022 (Built environment — Framework for competence of individual Principal Designers — Specification) is the published competence framework against which competence should be measured. The framework expects a documented competence assessment, evidence-based, project-specific, and updated as required.

Failure to discharge the duty can found criminal proceedings under section 35 of the Building Act 1984 (as amended by section 39 BSA 2022), with the maximum penalty for the most serious offences increased to unlimited fines and, in HRB cases, up to two years' imprisonment.

Civil liability — three routes

The Principal Designer is exposed to three principal civil liability routes:

Section 1 Defective Premises Act 1972 — for dwellings. The duty to see that work is done "in a workmanlike or, as the case may be, professional manner, with proper materials, and so as to be fit for habitation when completed" applies to designers. Limitation now runs for 30 years retrospectively / 15 years prospectively (see Spoke 1).
Section 38 Building Act 1984 — civil action for damage caused by breach of the Building Regulations. Limitation extended to 15 years prospectively by section 135 BSA 2022. Not subject to the retrospective extension.
Tort of negligence — the common law route. Limitation under the Limitation Act 1980 sections 2 and 14A. The DPA route has largely displaced it for residential cases because it avoids the Murphy v Brentwood economic-loss bar.

Criminal liability — section 35 Building Act 1984

Section 39 BSA 2022 amended section 35 of the Building Act 1984. The headline change: maximum penalties for offences committed by dutyholders under the Building Regulations are increased. The full schedule of offences is set out in the Building Act 1984 as amended; HRB offences carry the harshest penalties, with imprisonment available for the most serious breaches. A PI policy cannot indemnify against criminal fines, and many policies expressly exclude legal defence costs for criminal investigations.

The "competent person" defence

Section 35A of the Building Act 1984 (as amended) provides a defence to a person charged with an offence under section 35 if they prove they "took all reasonable steps and exercised all due diligence" to avoid commission of the offence. Documented competence frameworks, internal QA processes and trained staff are the foundation of this defence in practice.

The transitional cut-over

For projects that submitted a building control application (initial notice or full plans) before 1 October 2023, transitional provisions allowed continuation under the previous regime. The transitional cut-over caused real-world disputes during 2024 — including disputes about whether a particular project had been validly "transitioned" and therefore whether the new Principal Designer regime applied. The BSR has issued guidance, but boundary cases continue to arise.

The PI implications

Insurers now ask the question

Modern construction PI proposal forms ask explicitly whether the proposer has held Principal Designer status under Part 2A of the Building Regulations on any project, and if so, how many, of what scale, including how many HRBs. Some insurers have specific schedules and sub-limits keyed to the answer. Disclosure is critical — see Spoke 7.

The competence point is an underwriting point

An underwriter assessing the risk of writing PI cover for a practice that holds Principal Designer roles will want to see evidence of the practice's competence framework — recruitment standards, supervisory structures, CPD records, project-by-project competence declarations. This is no longer a paper exercise. Practices that cannot evidence a robust SKEB framework face higher pricing or restrictions.

Sub-limits and aggregation

Many insurers now apply an HRB-specific sub-limit to PI cover where the proposer holds Principal Designer roles on HRB projects. Sub-limit forms vary: aggregate sub-limit (commonly £1m–£5m in the aggregate, costs inclusive); "any one claim" sub-limit; sub-limit specific to Gateway 2 design errors; or full cover with a higher excess on HRB matters. The aggregation question — whether multiple errors on the same fire strategy aggregate to one claim — sits squarely within the wider aggregation analysis at the aggregation hub.

Criminal investigations and PI

PI does not indemnify criminal fines, and most policies do not respond to defence costs in a criminal investigation by default. Some PI wordings include a "regulatory" defence costs extension (often sub-limited) covering legal representation in front of a regulator. Read this extension carefully — it may not extend to an HSE / BSR prosecution and may not extend to anything beyond the formal hearings.

Personal exposure of named individuals

The Principal Designer is normally a corporate appointment (the practice), but the SKEB framework and the criminal-offence provisions attach to natural persons. Named individual partners and directors can face personal regulatory action, even where the corporate is also prosecuted. A Directors' and Officers' policy alongside the practice's PI is now essential for any partner or director of a practice operating in the HRB space.

Run-off implications

The Principal Designer's design choices found long-tail liability under the DPA 1972 and section 38 Building Act 1984. The combination of statutory duties and 30-year retrospective limitation makes the run-off question particularly acute for the architect or engineer planning to retire. See Spoke 8.

Worked scenario

Facts: A medium-sized architectural practice (12 directors, 80 staff, turnover £8m, PI limit £10m on each-and-every basis) is appointed as Principal Designer (Building Regulations) and lead architect on three HRB projects in 2024–2025. One is a 20-storey residential tower; two are 8-storey blocks on the same masterplan.

In late 2026, a Gateway 2 resubmission on the tower is rejected by the BSR for inadequate fire strategy. The strategy was prepared by a sub-consultant fire engineer; the architect signed the Gateway 2 application as Principal Designer. The developer suffers significant delay losses and intimates a claim against the architect. The BSR opens a separate regulatory enquiry into competence.

Issues for the architect's PI:

The architect's PI is a £10m limit, but the schedule includes an HRB sub-limit at £3m in the aggregate, costs inclusive.
The developer's loss is £4.5m, of which £2.8m is rectification, £1.2m is delay holding costs, and £0.5m is consultant fees.
The architect's appointment limits liability to £10m per project, includes a net contribution clause, and includes a fitness-for-purpose disclaimer.
The fire engineer sub-consultant carries £5m PI; their wording includes a fire safety carve-out.
The BSR enquiry triggers a request to the architect for production of the SKEB framework, project-specific competence declaration, and design management plan.

Likely outcome (illustrative):

The PI insurer accepts notification on the developer claim, subject to the HRB sub-limit and the costs-inclusive position.
Defence costs through to settlement are estimated at £400k, eroding the sub-limit.
A net contribution argument apportions liability between architect and fire engineer; the fire engineer's insurer disputes coverage under the fire safety carve-out.
The architect's "regulatory defence costs" PI extension responds to the BSR enquiry up to a £100k sub-limit; the remainder of legal fees is funded by D&O cover.
The eventual settlement is within the HRB sub-limit; the practice carries a meaningful excess and faces a renewal at a markedly higher premium.

The point: every layer of the architect's risk programme is exercised. The PI sub-limit, the costs-inclusive position, the regulatory defence extension, the D&O cover, the appointment limitation of liability, the net contribution clause, the subcontractor's PI cover, and the subcontractor's exclusion — all of these matter, simultaneously.

Sector-specific practical takeaways

Architectural practices: invest in the SKEB framework. Document the competence assessment for every Principal Designer appointment. Keep the design management plan version-controlled. Train every project lead.

Multi-disciplinary consultancies: when appointed across multiple disciplines on a single HRB, be explicit in the appointment about which entity holds which role. Conflict and ambiguity over who is the Principal Designer is a frequent cause of dispute.

Single-discipline architects subcontracting to a lead consultant: know your scope. If you are not the Principal Designer, ensure the appointment is clear; if you are nominally the Principal Designer but your scope is narrow, push back on the appointment wording.

Fire engineers: the Gateway 2 fire strategy is the highest-stakes single document on most HRB projects. Your scope of services should be explicit about what the architect can rely on. Subcontract terms should align with the head appointment.

Single-practitioner / very small practices: an HRB Principal Designer appointment is almost certainly beyond the SKEB resources of a one or two-person practice unless the practice has deep prior HRB experience. The PI market is increasingly unwilling to write the cover for very small practices on HRB work; consider whether you should be taking on these appointments at all.

Frequently asked questions

1. Is the Principal Designer role the same on HRB projects and non-HRB projects? The core duties under Part 2A apply to all projects subject to the Building Regulations. HRB projects add the Gateway 1/2/3 obligations, the golden thread, and additional competence and change-control duties.

2. Can the Client be the Principal Designer? Only if the Client has the relevant competence. In practice the Principal Designer is almost always the lead design consultant.

3. Does the Principal Designer take on liability for the work of other designers? The Principal Designer has a duty to coordinate the design and to monitor compliance. They do not "assume" other designers' liability — but a failure of coordination or monitoring is their own breach, for which they are liable.

4. What is the relationship between Part 2A and CDM 2015? Parallel regimes. CDM 2015 deals with construction health and safety; Part 2A deals with Building Regulations compliance. Most lead designers will be both the CDM Principal Designer and the Part 2A Principal Designer; the appointment should be explicit.

5. Is a fitness-for-purpose obligation imposed by the regime? The dwelling-level DPA 1972 duty has been described as a fitness-for-habitation duty, which is close to (but not identical to) fitness for purpose. The Part 2A regime requires compliance with the Building Regulations. Most PI policies exclude fitness-for-purpose obligations greater than the reasonable skill and care standard — read your wording.

6. What does a "competence declaration" look like? A written statement, signed by the appointed dutyholder, that the dutyholder has the SKEB necessary for the role on the project in question. Best practice is for the declaration to be supported by an internal SKEB assessment record on file.

7. Can I delegate the Principal Designer role to a sub-consultant? The role is conferred by appointment from the Client. The Principal Designer cannot unilaterally delegate the statutory role, although they can subcontract design tasks. The dutyholder remains the duty-holder.

8. Does the role attach to a project or to a practice? The role attaches to the appointed person (a corporate or an individual) for the project. A practice that takes on the role is the dutyholder; the individuals doing the work do so under that umbrella, but personal liability under criminal provisions can attach to identifiable individuals.

9. What does my PI policy mean by "Principal Designer"? Look at the definitions clause. Some PI wordings still use "Principal Designer" in the CDM 2015 sense; others have been updated for Part 2A; some define it independently. Misalignment between the regulatory scope and the policy definition is a real underwriting issue.

10. We declined to act as Principal Designer but were still listed in the Gateway 2 submission. Are we exposed? You may be. If your name is on a regulatory document as the Principal Designer, the BSR will treat you as one until told otherwise. Correct the documentation immediately and in writing; obtain the developer's confirmation that a substitute Principal Designer has been appointed.

Sources

Statute — Building Safety Act 2022 c.30, s.39; Building Act 1984 c.55, ss.35, 35A, 38; Defective Premises Act 1972 c.35, s.1.

Secondary legislation — Building Regulations etc. (Amendment) (England) Regulations 2023 SI 2023/911 (inserting Part 2A into the Building Regulations 2010); Construction (Design and Management) Regulations 2015 SI 2015/51.

Standards — PAS 8671:2022 (Built environment — Framework for competence of individual Principal Designers).

Guidance — Building Safety Regulator: dutyholder guidance for Principal Designers and clients; HSE published guidance on competence frameworks.

Where this fits

Disclaimer

This is legal and insurance commentary, not advice. The Building Safety Act 2022 regime is technical and fact-sensitive — consult specialist counsel and your broker on your specific position. Apex Insurance Brokers Limited is authorised and regulated by the Financial Conduct Authority, FRN 724952.