The short answer
CDM is the Construction (Design and Management) Regulations 2015, and on a commercial roof job the business is the client, with duties of its own. If only one contractor is working on the project, that contractor draws up a construction phase plan. Once more than one contractor is engaged, a principal designer and a principal contractor must be appointed. General information, not legal advice.
The client under CDM
CDM 2015 sets out how construction work is organised so that it is carried out safely. HSE's definition of a domestic client is a person having construction work done on their own home outside any business. A company, landlord or farm business paying for roof work on its own premises falls outside that, and is a commercial client.
A commercial client carries duties that a homeowner's contractor would otherwise pick up. In outline, the client appoints competent people, makes sure enough time and resources are allowed, and passes on the information a contractor needs about the building. For a roof that includes asbestos records, the location of services, fragile areas and the way the building is used.
The client also has to see that health and safety arrangements for the project are made and kept up. That is not supervising the work, but it does rule out leaving matters to chance or choosing a contractor on price alone.
Because the duties turn on who commissions the work, say plainly at the start who the client is. Where a managing agent organises the job, who holds the client role needs a written answer.
One contractor, or more than one
The size of the team on site changes what CDM asks. Regulation 5 requires principal designer and principal contractor roles to be filled once more than one contractor is engaged. The extra duties turn on that fact, not on whether the project must be notified to HSE.
A single roofing contractor working alone is the simpler case. The roofer then draws up the construction phase plan, as regulation 15(5) provides when there is only one contractor on the project. The plan describes how the work will be organised and the risks controlled.
The position changes as soon as another trade arrives. A roof replacement might involve the roofer, a scaffolder engaged separately, an electrician moving rooflight wiring and an asbestos contractor taking off old sheets. If these are engaged by the client separately, there is more than one contractor and the appointments are needed.
The client may appoint the principal contractor to manage the site and a principal designer to coordinate the design. Where the roofer takes everything on under one contract, the arrangement may stay simple. Ask early which structure applies, so the paperwork matches the reality. Our guide to roof work on an occupied building covers the people below.
Writing the site plan before work
The construction phase plan is the working document for the job. Its heading list is practical: a description of the work and the programme, who is in charge, how access is arranged, what the hazards are and how they will be controlled. For a roof, the usual hazards are falls from height and through fragile materials, falling objects, asbestos, lifting and noise.
A sound plan is proportionate. A repair to a single bay of a unit roof needs a short, clear plan, whereas a full re-roof over a working factory needs much more, including how traffic, staff and deliveries are kept apart from the work zone.
It is based on the information the client provides, which is why the asbestos register and survey, the building's drawings and any known problems should be passed over before the plan is written. A roofer given nothing has to plan for the worst, and the plan and the price both grow.
The plan is reviewed as the work goes on. If conditions change, say an opened roof reveals rotten timbers, it is updated and those affected are told. Our guide to fragile roof safety shows what that looks like on a sheet roof.
What to ask of a roofer, and what we do
Ask the roofer who they believe the client is, whether they are the only contractor, and what plan will be written. Ask when you will see the construction phase plan and what happens if the site changes. The answers show whether CDM is being treated as a real framework or as a form to be filled in.
On our side, we survey the roof first and record access, edges, fragile areas and anything that affects safety. We write the plan around what we find and share it before work begins. Where the building stays in use, the plan sets out how the work area is separated from the people below.
If the job involves more than one contractor, we flag it and ask the client to confirm who holds the appointments. We do not assume the answer.
Costs follow from the same facts: access equipment, edge protection, phasing and any specialist contractor. They reach you in a single written total once we have surveyed. The commercial roofing page shows the work we take on for business premises, and the page on a roof edge protection sets out the access side.
