A project falls under the Health and Safety Executive CDM Regulations 2015 as soon as it involves “construction work”, regardless of project size, cost, or whether it is domestic or commercial.
Construction work under CDM is defined broadly and includes activities such as building, demolition, extension, refurbishment, repair, maintenance, installation of services, and structural alterations. This means even relatively small jobs—such as a kitchen renovation, roof repair, or home extension—can fall under CDM if they involve construction activities.
CDM applies from the point the work is being planned and organised, not just when it physically starts on site. The key factor is whether the work involves construction operations and therefore requires health and safety to be properly managed.
In practice, CDM is triggered whenever construction work is taking place, and the level of documentation and management required depends on the risks involved and whether more than one contractor is working on the project.