I think in this case you are looking at employing a principal contractor rather than a principal designer.

The principal designer comes into play where there is a pre-construction phase where the project will need planning/design input from Engineers, architects, etc.

Assuming you are just replacing a roof like-for-like then the roofing company would simply become the principal contractor.

They would then need to oversee the project and Health & Safety including producing the Construction phase plan and for a small project like that CITB have an app they could use which would take them about 5 minutes:

http://www.citb.co.uk/he...ulations/cdm-wizard-app/

So it's not a single contractor project.

You need a PC and PD (or have the client take on all the duties)

The 'single contractor' condition in the regs is about if there is more than one contractor working on the project, not about the number of direct appointments made by the client.

I suppose you might try and generate a loophole if you bought the scaffold (rather than rented it) and appointed a scaffolder to erect it, then terminated that appointment before the roofer started on site, and then terminated the roofer's appointment before the scaffolder is appointed to come and clear the scaffold. I wouldn't want to try that as a defence in court, however.

Never really considered this scenario. If a client engaged an electrical company how would you know whether those employed on the project are self-employed or employees? I don't think you would. In which case a client would treat it as a single contractor project.

Thanks for all your comments.

As a result of the above replies, I have approached the client and insist they appoint a PD.

Client reply "Can we request the PC to pick up the Principal Designer role as they have influenced the design by putting together the roof specification"

PC reply "We cannot pick up the PD role as we do not have the correct level of Skills, Knowledge and Experience to be appointed PD"

Client response "Can you as Project Managers pick up the role of PD?"

Our response "Firstly we are not in a position to influence the design and secondly we don't have design insurance"

Client response "So who will be PD?"

Our response "you by default"

Client response "we don't want to be PD"

Our response "We can assist with you as PD as CDM advisor's subject to an additional fee"

Client begrudgingly accepted our additional fee offer.

Bit of a long drawn out conclusion to a relatively small project wouldn't you agree!!!!!

Consder yourself fortunate because if I was representing the client I would have insisted if you accept the project you would be both PC and PD. The role of PD is not onerous for small projects, indeed there is no more work than the PC would have done pre 2015 regs.