Principal designer
What does more than one contractor mean under CDM 2015?
Short answer
A contractor under CDM 2015 is anyone who manages or carries out construction work in the course of a business. More than one contractor means more than one such organisation or person working on the project at any time, and they do not have to be on site at the same time. A builder who brings in an electrician for a week has a project with more than one contractor, and the client must appoint a principal designer and a principal contractor in writing before work starts.
Where the definition comes from
The definition is in regulation 2 of CDM 2015: a contractor is a person who, in the course or furtherance of a business, carries out, manages or controls construction work. Three things follow from that wording.
It is about business, not about trade. A sole trader plasterer working for money is a contractor. A relative helping at the weekend for nothing is not.
It includes managing, not just doing. A builder who subcontracts every trade and never picks up a tool is still a contractor, because they manage and control the work.
It says nothing about size. A one person electrical business is a contractor in exactly the same way a national contractor is.
They do not have to overlap
This is the point most often got wrong, and the one that changes the answer on most domestic projects. The regulation says more than one contractor working on a project at any time, not at the same time. Sequential trades count.
Worked example. A loft conversion. The main builder does the structure and the finishes. A steel fabricator delivers and installs the beams in week two. A roofer forms the dormer in week four. An electrician wires it in week eight, and a plasterer finishes in week ten. At no point are two firms on site together. That is five contractors, and the project needed a principal designer from the day it was reasonably foreseeable that it would go that way.
Reasonably foreseeable
The trigger in regulation 5(1) is not only where there is more than one contractor, but also where it is reasonably foreseeable that there will be. You do not get to wait and see.
If a design includes a new consumer unit, a gas connection, structural steel or a roof covering that the main builder does not do themselves, a second contractor is reasonably foreseeable at design stage, which is exactly when the appointment is supposed to be made.
Where the line really falls
| Situation | More than one contractor? |
|---|---|
| Builder does everything, employs their own staff | No. One contractor with employees is still one contractor |
| Builder plus a subcontracted electrician | Yes |
| Builder, then a separate kitchen fitter you engage directly | Yes |
| Builder plus a scaffolding company | Yes. Scaffolding is construction work |
| Builder plus a skip hire company | Delivering a skip is not construction work. Erecting, altering or dismantling structures, and site clearance, are |
| You doing part of the work yourself, on your own home, unpaid | Not a contractor. HSE guidance treats work not carried out by someone on the client's behalf as DIY, outside CDM 2015 altogether |
What this means for you
For most domestic extensions, lofts and refurbishments the honest answer is that the project has more than one contractor and the appointment is required. The useful question is not whether you can find a reading that avoids it, but who is going to hold the role and be resourced for it.
Sources
- The Construction (Design and Management) Regulations 2015 legislation.gov.uk
- CDM 2015, regulation 5: appointment of the principal designer and the principal contractor legislation.gov.uk
- HSE: contractors, roles and responsibilities hse.gov.uk
- Managing health and safety in construction, L153 HSE guidance on the Regulations
Find out where your project stands
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