Every commercial tenant commissioning a CAT B fit-out is a 'client' under CDM 2015. Most don't realise the statutory duties that attach. This guide explains what a tenant is actually responsible for, how to discharge those duties, and what happens when you don't.
The Construction (Design and Management) Regulations 2015 apply to every construction project — including commercial office fit-out, refurbishment, dilapidations works and renovation. There's no size threshold for whether CDM applies; only for whether the project is notifiable to the HSE (30+ working days and more than 20 workers simultaneously, or over 500 person-days).
The person commissioning the works is the client. For commercial fit-out, that's almost always the tenant — even if the landlord is contributing.
Under CDM 2015 Regulation 4, the client must:
The principal designer (PD) is responsible for planning, managing and monitoring the pre-construction phase. The principal contractor (PC) does the same for the construction phase. Both are mandatory appointments when more than one contractor is on site — which is every CAT B fit-out.
Tenants have three options:
Standard practice. The main fit-out contractor takes PC duty. Most commercial contractors (including us) are competent to hold PC and carry the required insurance.
Standard practice on larger projects. Where no architect is engaged, the contractor can often hold both PD and PC roles through in-house design capability.
Sister practice Hampstead Chartered Surveyors offers standalone PD service. Typical fee 0.5–1.5% of works value.
If a project is projected to exceed 30 working days with more than 20 workers simultaneously, or 500+ person-days, the project is notifiable. The client must submit Form F10 to the HSE before work begins.
Rough thresholds for commercial fit-out:
Notifying incorrectly (or failing to notify when required) carries HSE enforcement risk. The F10 submission is trivial — it takes 10 minutes online — but missing it is a strict liability offence.
Before any work starts, a construction phase plan (CPP) must exist. This is the principal contractor's document describing how H&S will be managed. The client doesn't write it — but the client must ensure it exists and is suitable before mobilisation.
The client provides this to the design team at project outset. For commercial fit-out, the pack typically includes:
At project completion, the principal designer compiles the H&S file — the record of built works for future maintenance, alteration and eventual demolition. The client must preserve this for the life of the building and pass it to subsequent owners or tenants.
Common client failure: treating the H&S file as "the contractor's problem" and discarding it at handover. This breaches CDM 2015 Regulation 4(7).
HSE can prosecute under CDM 2015. Typical penalties at Magistrates' Court: up to £20,000 per offence plus unlimited Crown Court fines. Directors can face personal prosecution under the HSWA 1974. Insurance doesn't cover criminal penalties.
Reality check: HSE prosecution of tenants is rare unless an incident occurs. The real risk is being on the wrong side of an incident with an undischarged client duty.
For our fit-out clients, we handle:
See our full Office Fit-Out service, Office Refurbishment, and area pages for City of London, Canary Wharf and Westminster & Victoria.
For tenant CAT B fit-out, the tenant is the client. For landlord CAT A works, the landlord is the client. Where the landlord contributes to a tenant fit-out, the tenant still holds client duties.
Only where more than one contractor is involved — which includes virtually every CAT B fit-out. For a pure single-trade job (e.g. a decorator-only refresh), PD is not required.
Strict liability offence. HSE can prosecute regardless of whether an incident occurred. The F10 is online and free — just submit it.
Yes — if the company is competent for both roles and the client is satisfied. Many design-and-build contractors do this on smaller projects.
Measured survey and fixed-price quote within 10 working days.