Professional Indemnity Insurance for CDM Principal Designers

Reviewed by Matthew Bartlett, Director, Apex Insurance Brokers Limited · Last reviewed 2026-08-05

Who the CDM Principal Designer is

The Construction (Design and Management) Regulations 2015 (CDM 2015), enforced by the Health and Safety Executive (HSE), create the role of Principal Designer. The client must appoint one on any project where more than one contractor is, or is reasonably expected to be, involved. The Principal Designer is a designer — an individual or organisation — with control over the pre-construction phase.

The duties are practical and specific. You plan, manage and monitor the pre-construction phase; co-ordinate health-and-safety matters so that, so far as is reasonably practicable, the project is designed to be built, maintained and eventually demolished safely; help the client compile pre-construction information; and prepare the health-and-safety file. Where you fall short, and someone relies on that work to their cost, a professional negligence claim can follow.

Note: the CDM 2015 Principal Designer is a different legal role from the "principal designer" dutyholder introduced under the Building Safety Act 2022 and the Building Regulations 2010 (dutyholder amendments in force from October 2023). Many firms hold both roles. Tell your broker exactly which appointments you take — the risk profiles are not identical.

What PI insurance actually covers here

PI insurance responds to your legal liability to third parties for a breach of professional duty — negligence, error or omission in the services you provide. For a CDM Principal Designer, the exposures are distinct from a general design PI risk because the role is largely one of co-ordination and management rather than producing the design itself.

• Design co-ordination liability: a claim that you failed to identify or manage a foreseeable buildability, maintenance or safety risk across designers' contributions.
• Pre-construction information failures: incomplete or inaccurate information passed to the Principal Contractor, leading to loss, delay or an unsafe method of work.
• Health-and-safety file defects: an inadequate file that causes cost or harm during later maintenance, refurbishment or demolition.
• Advice and monitoring: allegations that you did not adequately plan, manage or monitor the pre-construction phase as CDM 2015 requires.
• Defence costs: legal costs of investigating and defending a claim, which frequently exceed the sum eventually paid.

Most UK PI wordings for construction professionals are written on a civil liability basis, meaning they respond to any civil claim arising from your professional services, not just proven negligence. That breadth matters for a co-ordinating role where the boundary of your duty can be argued after the event.

Is PI insurance a legal requirement?

CDM 2015 does not oblige a Principal Designer to hold PI insurance. There is no HSE-mandated minimum. In practice, though, cover is effectively unavoidable for three reasons:

• Client appointments. Almost every professional appointment or consultancy agreement requires PI cover at a stated limit — often £1m, £2m or £5m — maintained for a set number of years after completion.
• Professional bodies. If your firm is on the ARB register or is an RIBA Chartered Practice, PI cover is a condition of registration. Architects, engineers and surveyors taking the PD role bring those existing obligations with them.
• Commercial reality. Without cover, a single defence-cost bill can threaten the practice, and most clients simply will not engage an uninsured dutyholder.

So while the answer to "must I have it?" is technically no under CDM, the working answer is yes: your contracts and your regulator will require it.

Choosing a limit of indemnity

The right limit depends on the value and complexity of the projects you co-ordinate, and on what your appointments demand. There is no fixed formula, but these generic bands help frame the conversation:

Watch how the limit applies. PI can be written each and every claim or in the aggregate (a total for the policy year). Some appointments require an each-and-every basis, so check what your contracts demand before you buy. Also confirm whether defence costs sit inside the limit or in addition to it.

The features that matter most for this role

• Claims-made basis. PI responds to claims made during the policy period, whenever the underlying work was done. Let cover lapse and a later claim about past work may be uninsured.
• Retroactive date. This sets how far back your cover reaches. For a Principal Designer, unlimited retroactivity (or a date covering all prior appointments) protects work already completed.
• CDM duties explicitly recognised. The policy should cover your activities as a CDM 2015 dutyholder, not just conventional design. Because the PD role is co-ordinating and advisory, wording that only contemplates design output can leave gaps.
• Run-off cover. If the practice closes, merges or you retire, run-off keeps the claims-made cover alive for past PD appointments — often required by contract for several years after completion.
• Fitness-for-purpose exclusions. Standard wordings usually exclude liabilities you take on beyond reasonable skill and care. If an appointment imposes a stricter standard, flag it — it may be uninsurable.

How Apex places Principal Designer PI

We are a UK insurance broker, authorised and regulated by the Financial Conduct Authority, and we arrange PI for construction professionals who hold CDM dutyholder roles. Our approach:

• We map your appointments. Which projects, what values, whether you also act as designer, Principal Contractor or Building Safety Act principal designer — each changes the risk and the wording you need.
• We match limits to your contracts. We check the indemnity limit, aggregation basis and run-off periods your appointments require, so your cover satisfies them rather than leaving you personally exposed.
• We place with insurers who understand the role. We approach UK PI markets experienced in construction and dutyholder liability, and read the wording for exclusions that would bite on co-ordination work.
• We support you at claim and renewal. If a claim or circumstance arises, notify early — on a claims-made policy, prompt notification protects your position.

Ready to start? Tell us about your Principal Designer appointments and we will tailor terms to what your contracts actually require.

Common questions

Does the CDM Principal Designer role need separate PI, or is my design PI enough?

Often one policy can cover both, but only if the wording recognises your CDM dutyholder activities. Because the PD role is about co-ordination and advice rather than producing the design, a policy written purely around design output can leave gaps. Ask your broker to confirm the role is captured.

How long should I keep cover running after a project finishes?

PI is claims-made, so it must be in force when a claim is brought — possibly years after completion. Your appointment will usually state a period for which cover must be maintained. Continue the policy, or arrange run-off if you stop trading, for at least that period.

Is PI insurance a legal requirement for a Principal Designer?

Not under CDM 2015 itself, and the HSE sets no minimum. In practice your client appointments, and professional bodies such as ARB or RIBA where they apply, will require it — and few clients will engage an uninsured dutyholder.

Apex Insurance Brokers Limited is authorised and regulated by the Financial Conduct Authority (FRN 724952). This guide is general information, not advice on a specific policy or a substitute for your policy wording.