Technically, you have legal duties the moment you commission building work on your own home. In practice, the law is designed so those duties land on your contractor automatically — as long as you understand how the transfer actually works.
Why homeowners have duties under CDM 2015 at all
The Construction (Design and Management) Regulations 2015 apply to all construction work in the UK, including projects for "domestic clients" — private homeowners renovating their own home, not acting in the course of a business. CDM 2015 exists to reduce accidents and protect workers, homeowners, and the public by ensuring construction work is properly planned, managed, and carried out safely, even on small residential jobs.
The correction worth getting right: the transfer is automatic
Here's the detail that's easy to get backwards: a domestic client's CDM duties transfer automatically — by default, with no written agreement needed — to the contractor (on a single-contractor project) or the principal contractor (where more than one contractor is involved). You don't need to draft anything for this transfer to take legal effect; it happens by operation of the regulations themselves.
A written agreement only becomes relevant if you want something different from the default — specifically, if you want a designer (such as an architect) to take on those duties as principal designer instead of the contractor. Without that specific written agreement, the duties default to the principal contractor regardless of who else is involved in the project.
What you still need to do, even with duties transferred
- Make reasonable checks on the competence of anyone you hire, including asking about their track record managing health and safety
- Allow sufficient time and money in the contract for work to be carried out safely — a contract that pressures unrealistic speed undermines this
- On multi-contractor projects, be aware that a principal designer and principal contractor should be appointed — even though you personally won't be the one appointing or notifying under CDM, since that responsibility has transferred
When the project needs formal HSE notification
If the work is expected to last longer than 30 working days with more than 20 workers on site at any one time (or meets an equivalent alternative threshold), it must be formally notified to the Health and Safety Executive (HSE). On a domestic project, this notification duty falls to the principal contractor or principal designer, not to you as the homeowner — but it's worth confirming with your contractor that they understand and will handle this if your project is large enough to trigger it.
The practical risk if nobody takes responsibility
The main real-world risk isn't that you'll personally be prosecuted for a paperwork failure — it's that if a multi-contractor project has no principal contractor formally in place, responsibility falls into a genuine grey area that nobody wants to be in if an accident happens. Confirming clearly, in writing, who is acting as principal contractor is a simple step that closes this gap.
What this means practically
- Your CDM 2015 duties as a homeowner transfer automatically to your contractor — you do not need a written agreement to achieve this transfer.
- A written agreement is only needed if you want a designer, rather than the contractor, to take on these duties instead.
- You still play a real role: check competence, and budget realistic time and money for the work to be done safely.
- On larger, multi-contractor projects, confirm explicitly who is acting as principal contractor — an unclear chain of responsibility is the actual risk, not a compliance technicality.
Sources
- HSE — Domestic clients: roles and responsibilities: hse.gov.uk
- HASpod — CDM 2015 Domestic Clients and Work on Residential Projects: haspod.com
Related Kibbo Tools
- Contractor Verification Checklist — check a contractor's safety track record before they take on CDM responsibilities for your project.