Construction (Design and Management) Regulations 2015 apply to almost every office fit-out. Here's what tenant clients need to know about their legal duties.
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What this guide covers
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When CDM 2015 applies
The Construction (Design and Management) Regulations 2015 apply to virtually every commercial fit-out and refurbishment in the UK. Triggers include: any project where construction work will last more than 30 days with more than 20 workers on site at any one time, OR exceeding 500 person-days of construction work, OR involving more than one contractor. In practice, this means almost every office fit-out triggers CDM duties — only the very smallest minor works are exempt.
The client's legal duties under CDM
As the tenant client, you have non-delegable legal duties: appoint a competent principal contractor (in writing); appoint a competent principal designer (in writing) where multiple designers are involved; ensure the project is suitably resourced including time and budget; provide pre-construction information (asbestos surveys, existing building drawings, services plans); ensure principal contractor has prepared a construction phase plan before mobilisation; ensure a health and safety file is delivered at handover. Failing in any of these duties exposes the client to criminal liability under HSE enforcement.
The principal contractor and principal designer roles
The principal contractor manages site-based health and safety throughout the construction phase. The principal designer manages design risk before site mobilisation — a relatively new requirement under CDM 2015. Where we are appointed as both, we hold both roles with documented competence. Where the client retains a separate architect or designer, we coordinate with them as principal contractor and they may take principal designer. The roles must be in writing — a verbal appointment is non-compliant.
What you should expect from your contractor
On every CDM-applicable project, your contractor should provide: a written CDM appointment letter taking principal contractor (and PD where applicable); a construction phase plan before site mobilisation; F10 notification to HSE for projects over 30 days/500 person-days; weekly site H&S reports to client; CDM-compliant H&S file at handover. The H&S file is your record of how the building was modified, including hazardous materials managed, and is required for any future works on the same space.
Frequently Asked Questions
Can the client appoint themselves as principal contractor?
Only with documented competence in construction H&S management. Most clients appoint a contractor as principal contractor and retain that role through the contract.
What's the F10 notification?
A formal HSE notification required for projects over 30 days with more than 20 workers, or over 500 person-days. Submitted by principal contractor before mobilisation.
What happens if we skip CDM compliance?
HSE enforcement can include improvement notices, prohibition notices (stopping work), and prosecution. Penalties include unlimited fines for clients and contractors.
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