Construction sub-consultants · PII
PI insurance for UK construction sub-consultants and specialist designers
Reviewed by Matthew Bartlett, Director, Apex Insurance Brokers Limited · Published 14 July 2026
Construction sub-consultants — specialist designers, technical consultants, and single-discipline engineers — operate within complex supply chains with distinctive PI considerations. Novation, warranty, D&B relationships and BSA 2022 tail exposure all shape the market.
Who this applies to
- Specialist designers (façade, acoustic, lighting, sustainability) sub-consulting to lead architects or engineers.
- Sub-consulting engineers in specific disciplines.
- Novated designers transferred from client to contractor in D&B arrangements.
- Technical consultants providing specific expertise to construction projects.
- Cost consultants and quantity surveyors operating as sub-consultants.
The supply-chain PII landscape
- Lead consultant carries the client-facing relationship.
- Sub-consultants have contractual relationship with the lead.
- Collateral warranties typically flow to funders, tenants, buyers.
- Novation transfers appointment from client to contractor in D&B.
- BSA 2022 s.135 extends limitation for higher-risk-building work regardless of sub-consultant status.
Common claim triggers
- Design error in the sub-consultant's discipline. Façade failure, acoustic issue, cost mis-estimate.
- Integration failure. Sub-consultant's design doesn't integrate with lead consultant's work.
- Missed brief. Sub-consultant's scope misunderstood.
- Warranty-recipient claims. Funder or tenant claims under collateral warranty.
- Post-novation contractor claims. D&B contractor pursues novated designer.
- BSA higher-risk-building tail. Historic sub-consultant work on higher-risk buildings.
Cover considerations
- Cover-limit should reflect the sub-consultant's specific liability, not just proportional-share of the project.
- Aggregation across multiple projects with the same lead consultant.
- Collateral warranty exposure to third parties.
- Novation clauses in appointment — PI must respond to novated context.
- BSA 2022 exposure for higher-risk-building work.
- Territorial scope for cross-border projects.
Cover-sizing
- Small specialist consultancy — typically £2m-£5m per claim.
- Mid-market sub-consultancy firm — £5m-£10m.
- Specialist BSA-touching sub-consultant — higher cover reflecting extended tail.
- Firms serving major infrastructure projects — layered programmes.
- Cost consultants and QS — sized to project values and appointment complexity.
Frequently asked
Do construction sub-consultants need their own PI insurance?
Yes typically. Sub-consultant appointment agreements typically require PI cover appropriate to the scope. Lead consultant's PI covers the lead's activity; sub-consultants need their own for their specific work.
How does novation affect my PI as a sub-consultant?
Under D&B novation, your appointment transfers from client to contractor. PI must respond to the novated context — some wordings restrict cover for novated appointments. Confirm at inception.
What is a collateral warranty and how does it affect my PI?
A collateral warranty extends the consultant's contractual liability to a third party (funder, tenant, buyer). PI wording must respond to warranty-recipient claims. Discuss with specialist broker.
Do I need higher PI cover if I do BSA-touching sub-consulting?
Yes. BSA 2022 s.135 extends limitation for higher-risk-building work. Historic sub-consulting on higher-risk buildings sits inside the extended tail. Cover limits should reflect this.
Am I liable if the lead consultant makes an integration error using my design?
Depends on the specific facts. Where the sub-consultant's design was correct within its scope, and the integration error was the lead's, the sub-consultant typically isn't liable. Documentation supports the defence.
What if my contract has a net contribution clause?
Net contribution clauses limit each party's liability to a fair share. Standard in construction contracts. Enforceability subject to reasonableness. Discuss with legal advisor.
How does my PI cover interact with the lead consultant's PI?
Both policies may respond to a claim depending on the specific facts. Coordination between the two insurers at claim time. Wording specifics matter.
Do sub-consultants need long run-off cover?
Yes for BSA-touching work. Historic sub-consulting on higher-risk buildings sits inside the 15-30 year BSA tail. Run-off cover should last accordingly.