CDM is the Construction (Design and Management) Regulations, and it applies to every construction project in Great Britain, including domestic ones. Contractors meet it most often as a request for information before they set foot on site, which is why it is worth understanding as a set of ROLES rather than as paperwork. The regulations name duty holders and say what each owes; almost everything a small contractor is asked for follows from which of those roles it is holding on that job.
The duty holders, and which one you are
The client commissions the work. The principal designer plans and manages the pre-construction phase; the principal contractor does the same for the construction phase where more than one contractor is involved. Designers, contractors and workers hold the rest. On a small job with one contractor, that contractor picks up duties the principal contractor would otherwise hold.
The construction phase plan is the document
Every project needs a construction phase plan before work starts, proportionate to the job: the description, the management arrangements, the site rules and the arrangements for controlling the significant risks. A plan for a bathroom is a page; a plan for a commercial fit-out is not. Writing none at all is the failure a site will actually catch.
Notification, the file and what is handed over
Larger or longer projects are notifiable to the regulator, and the thresholds are stated in the regulations rather than judged. At the end, the health and safety file passes to the client with what the next person working on the building needs to know. Both are the client's duty and both are usually asked of the contractor.
Questions people ask about cdm
Does CDM apply to domestic work?
Yes. The regulations apply to domestic clients, with the client duties normally passing to the contractor or, where there is more than one contractor, to the principal contractor unless the client agrees otherwise in writing with the principal designer.
What is asked for at the gate?
Usually the construction phase plan, your risk assessments and method statements, evidence of competence and training, and your insurance. Having them prepared as a pack rather than assembled per request is most of the work.
Is CDM the same across the UK?
The regulations extend to Great Britain; Northern Ireland has its own equivalent. If you work across that boundary, check which applies rather than assuming the pack you keep is sufficient.