Which role is which
CDM principal designer vs Building Regulations principal designer: what is the difference?
Short answer
There are two entirely separate principal designer roles in current English construction regulation. The CDM principal designer is appointed under regulation 5 of CDM 2015 and deals with health and safety through the pre-construction phase. The Building Regulations principal designer is appointed under Part 2A of the Building Regulations 2010, in force since 1 October 2023, and deals with designing the work to meet the Building Regulations. A project can need both. Being appointed to one does not appoint you to the other.
The comparison
| CDM principal designer | Building Regulations principal designer | |
|---|---|---|
| Legislation | Construction (Design and Management) Regulations 2015 | Building Regulations 2010, Part 2A, inserted by the Building Regulations etc. (Amendment) (England) Regulations 2023 |
| In force | 6 April 2015 | 1 October 2023, England |
| Concerned with | Health and safety in design and through the pre-construction phase | Designing the building work to comply with the Building Regulations |
| Appointed by | The client, in writing, regulation 5(1) | The client, in writing, regulation 11D(1) |
| Trigger | More than one contractor, or reasonably foreseeable | More than one contractor, or reasonably foreseeable |
| Who it must be | A designer with control over the pre-construction phase | A designer with control over the design work |
| If nobody is appointed, domestic client | Regulation 7(2): the designer in control of the pre-construction phase is the principal designer | Regulation 11C(2): the designer in control of the design phase is the principal designer |
| If nobody is appointed, other clients | Regulation 5(3): the client carries the duties | Regulation 11D(5): the client carries the duties until an appointment is made |
| Key outputs | Pre-construction information, design risk coordination, health and safety file | Coordination of design for Building Regulations compliance, and a report to the client within 28 days of the appointment ending |
| Does not apply to | Nothing by size; the trigger is the contractor test | Minor work, meaning work described in Schedule 4 of the Building Regulations, under regulation 11P |
| ClearCDM | Yes, this is the role we take | No. Not provided, and stated on every quote |
The certification route, and why it matters
There is one connection between the two regimes, and it is the thing most likely to cause an accidental problem.
Regulation 11D(2) of the Building Regulations 2010 allows a client, instead of appointing a person for the purposes of those Regulations, to certify in writing that the person who is the CDM principal designer is treated as appointed as the principal designer under the Building Regulations. The same route exists for the principal contractor.
That is a convenience for projects where one organisation genuinely holds both roles. It is a trap where it does not. If a client certifies that their CDM principal designer is also the Building Regulations principal designer, and that organisation does not provide the Building Regulations role, the project now has a nominal appointment and nobody actually coordinating design for Building Regulations compliance.
If ClearCDM is your CDM principal designer, do not use the 11D(2) certification route for us. We do not provide the Building Regulations principal designer role. The Building Regulations appointment should be made separately, normally to whoever leads the design.
A worked scenario
A £200,000 refurbishment of a London house. An architectural practice leads the design. A structural engineer designs the steelwork. A main contractor is appointed and subcontracts electrics, roofing and plastering. The client lives in the house and is a domestic client. The work is well beyond anything in Schedule 4, so it is not minor work.
| Question | Answer |
|---|---|
| More than one contractor? | Yes, several |
| CDM principal designer required? | Yes. The client must appoint one in writing before the construction phase begins |
| Building Regulations principal designer required? | Yes. Regulation 11D applies on the same more than one contractor trigger |
| If the client appoints neither? | Regulation 7(2) of CDM 2015 makes the designer in control of the pre-construction phase the CDM principal designer. Regulation 11C(2) makes the designer in control of the design phase the Building Regulations principal designer. On this project both are the architectural practice |
| Is the project notifiable to HSE? | Almost certainly not. It will not have more than 20 workers on site simultaneously, and is unlikely to exceed 500 person days |
Two separate appointments, one project, and on a normal domestic job both defaults land on the same practice if the client does nothing.
Why the names are so confusing
Because the second one borrowed the first one's name. The Building Safety Act 2022 and the regime that followed it introduced dutyholder duties into the Building Regulations that are deliberately shaped like the CDM ones: a client, a principal designer, a principal contractor, appointments in writing, and a default where a domestic client appoints nobody. The structure is parallel and the vocabulary is identical, but the subject matter is not.
One is about people getting hurt building and maintaining the thing. The other is about the thing meeting the Building Regulations.
What this means for you
Clients: you may have two appointments to make, not one. Ask each supplier which role they are providing, in writing, and do not assume one covers the other.
Design practices: the Building Regulations principal designer role is a natural fit for whoever leads the design. The CDM role does not have to be, and can go to a specialist instead. How to place it.
Everybody: the certification route in 11D(2) is only sensible where the same organisation genuinely does both jobs.
Parallel Architecture, which shares an owner with ClearCDM, sets out the same comparison from the Building Regulations side: the Building Regulations principal designer and the CDM principal designer.
Sources
- CDM 2015, regulation 5: appointment of the principal designer and the principal contractor legislation.gov.uk
- CDM 2015, regulation 7: application to domestic clients legislation.gov.uk
- CDM 2015, regulation 11: duties of a principal designer legislation.gov.uk
- The Building Regulations 2010, Part 2A: dutyholders and competence legislation.gov.uk
- Building Regulations 2010, regulation 11C: domestic clients legislation.gov.uk
- Building Regulations 2010, regulation 11D: principal designer and principal contractor legislation.gov.uk
See which roles your project needs
The free checker asks about contractors, designers and appointments, then shows the position on the CDM role and flags where the Building Regulations role needs a separate appointment.
Open the dutyholder checker →Not sure yet? get a fixed fee for the CDM role.