CDM 2015 and the Building Safety Act for domestic builders: what you actually have to do
Two sets of rules now apply to every domestic building project, and most builders are complying with neither in writing. The Construction (Design and Management) Regulations 2015 have applied to domestic work for ten years. The Building Safety Act added a second set of dutyholder roles under the Building Regulations from October 2023. Neither is complicated for an extension or a loft, but both expect you to have documents you can show.
CDM 2015: the domestic client's duties are yours
A domestic client is a homeowner having work done on their own home. Their CDM duties transfer automatically: to the contractor if there is only one, or to the principal contractor if there is more than one contractor on the project. Almost every extension has an electrician and a plumber as well as the builder, so the builder is usually the principal contractor and carries the client's duties too.
That means you must:
- Plan, manage and monitor the construction phase so that work is carried out without risk to health and safety
- Prepare a construction phase plan before work starts, for every project, however small
- Ensure suitable welfare facilities: a toilet, washing facilities, drinking water and somewhere to eat and dry clothes
- Make sure workers are inducted, competent and supervised
- Secure the site against unauthorised access, particularly children
- Liaise with the principal designer where one exists, and keep the health and safety file information
Do you need a principal designer?
Where there is more than one contractor, a principal designer must be appointed for the pre-construction phase. On domestic work, if the client has an architect, the architect usually takes that role by default. If there is no designer, the duty falls on the builder, who should write down what the design risks are (asbestos, structural stability during the works, working at height) and how they are being managed.
When to notify the HSE
A project must be notified on form F10 if the construction work is expected to last more than 30 working days and have more than 20 workers on site at the same time at any point, or to exceed 500 person-days. A big extension with four people on site for four months is about 350 person-days: not notifiable. A two-house development usually is. The notification is free and online.
The construction phase plan
This is the document inspectors ask for. For a domestic job it is a few pages: the project description and contacts, the programme, the site rules, the key risks on this job and how each is controlled (working at height, excavations, demolition, manual handling, dust, services, asbestos), welfare arrangements, first aid and emergency procedures, and how the plan is communicated to everyone on site. It must be in place before work starts and kept up to date.
Add site-specific RAMS for the higher-risk activities and a COSHH assessment for the materials you use. A toolbox talk record every week shows the plan is live. EstiMate produces the construction phase plan, RAMS, COSHH and toolbox talks from the job details so the pack is done in minutes rather than copied from the last job.
Building regulations dutyholders
Since 1 October 2023, every project that needs building regulations approval has a client, a principal designer and a principal contractor under the Building Regulations, with duties to plan, manage and monitor compliance with the regulations themselves, not just safety. On a domestic job with more than one contractor, the builder is usually the principal contractor and must be competent to manage compliance: Parts A, B, L, P and the rest. The client must appoint in writing; where they do not, the duty falls on whoever controls the work.
Practically: get the building control application in before you start, keep the inspection records, make sure every certificate (electrical, gas, glazing, structural) is collected, and give the client the completion certificate and the handover information at the end. Their solicitor will ask for it when they sell.
Keep the evidence on the job
Inductions, toolbox talks, inspections, the daily record of who was on site and what happened. A site diary with photographs does this with the least effort and is what proves compliance when an inspector or an insurer asks a year later. Put the documents in the same place as the job and the handover pack assembles itself.
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