CDM Regulations and Your London Renovation: What Clients Need to Know

The Construction (Design and Management) Regulations 2015 (CDM 2015) are the primary legal framework for health and safety management in construction projects in Great Britain. They apply to virtually every significant building project — including domestic renovation — and they impose specific legal duties on clients, designers, and contractors.

Many residential renovation clients are surprised to learn that they have legal obligations under CDM. The regulations are not restricted to large commercial developments; they apply to domestic projects above certain thresholds, and the client's duties are real and enforceable. Understanding them before a project starts is not merely good practice — it is a legal requirement.

The duty holders under CDM 2015

CDM 2015 identifies four categories of duty holder, each with specific responsibilities:

The client

The client is the person or organisation for whom the construction project is carried out. For a domestic renovation, this is the homeowner. The client's duties under CDM 2015 include:

• —Making suitable arrangements for managing the project, including allocating sufficient time and resources
• —Ensuring that the principal designer and principal contractor are appointed in writing (for notifiable projects)
• —Ensuring that a Construction Phase Plan is prepared before construction begins
• —Ensuring that a Health and Safety File is compiled and handed over at completion

The client duty cannot be delegated away. Even if the client appoints a project manager, the legal duty remains with the client. A client who is unaware of their obligations does not avoid them — they simply risk non-compliance.

The principal designer

The principal designer (PD) is a designer appointed by the client to plan, manage, and coordinate health and safety during the pre-construction phase. For most residential renovation projects, this will be the architect or lead designer.

The PD's role includes:

• —Planning, managing, monitoring, and coordinating pre-construction health and safety
• —Identifying and eliminating or controlling foreseeable risks during the design phase
• —Ensuring the design incorporates adequate provision for construction phase health and safety
• —Preparing and maintaining the pre-construction information pack
• —Liaising with the principal contractor on matters affecting the construction phase

The principal contractor

The principal contractor (PC) is the contractor appointed by the client to manage the construction phase. For a single-contractor residential renovation, the main contractor takes on the PC role.

The PC's duties include:

• —Planning, managing, and monitoring the construction phase
• —Preparing and implementing the Construction Phase Plan
• —Consulting and engaging with workers on health and safety matters
• —Ensuring suitable welfare facilities are provided on site

Designers and contractors

All designers (architects, structural engineers, interior designers, specialist subcontractors who influence design) and all contractors have duties to eliminate or reduce foreseeable health and safety risks in their work, and to cooperate with other duty holders.

When do CDM 2015 duties apply?

CDM 2015 applies to all construction work, including domestic renovation. The specific requirements differ depending on the scale of the project:

All projects (no threshold)

For every construction project, the client must: - Make suitable arrangements for managing the project so that construction can be carried out without risks to health and safety - Ensure welfare facilities are available for workers - Ensure a Construction Phase Plan is prepared before construction work begins (this can be a simple document for small projects)

Notifiable projects

A project is notifiable to the HSE if the construction phase will last longer than 30 working days with more than 20 workers simultaneously, or exceed 500 person-days. This threshold applies to most significant whole-house renovations.

For a notifiable project, additional duties apply: - A principal designer must be appointed in writing before detailed design begins - A principal contractor must be appointed in writing before construction begins - The project must be notified to the HSE using the F10 online notification form - A Health and Safety File must be compiled and handed to the client at completion

For a whole-house renovation in prime London — lasting several months with multiple trades on site — the notifiable threshold is very likely to be exceeded. Many clients and their contractors overlook this, which constitutes a breach of the regulations.

The Construction Phase Plan

The Construction Phase Plan (CPP) is the key document required before construction begins. It sets out the health and safety arrangements for the construction phase, including:

• —A description of the project and the nature of the risks
• —The management arrangements (how the PC will manage health and safety)
• —The arrangements for controlling significant site risks (confined spaces, underground services, asbestos, temporary works)
• —Site rules (working hours, visitor procedures, emergency arrangements)
• —Fire safety arrangements

For a small domestic renovation, the CPP can be a concise document. For a complex whole-house renovation with multiple overlapping trades, deep excavation, and specialist works, it will be more extensive.

The CPP is a live document — it should be updated as the project progresses and as new risks emerge.

The Health and Safety File

The Health and Safety File (HSF) is a document compiled during the project and handed to the client at completion. It contains information needed for future maintenance, repair, or construction work on the building, including:

• —As-built drawings showing the structural configuration, M&E layouts, and positions of services
• —Information on materials used (particularly hazardous materials such as asbestos-containing materials that have been encapsulated rather than removed)
• —Operating and maintenance instructions for installed plant and equipment
• —Residual risks that could affect future work (for example, retained ACMs)

For a client planning to sell the property, the HSF is a valuable document — it provides the information that subsequent owners and their contractors need to work safely on the building.

Common compliance failures in prime London renovation

The most common CDM compliance failures on domestic renovation projects in London are:

1. 1.No written appointment of principal designer — often because the client and architect have an informal relationship and the formal CDM appointments are not made
2. 2.No Construction Phase Plan before work starts — the PC either does not know they must prepare one, or does not do so before mobilisation
3. 3.Failure to notify the HSE on notifiable projects — many clients and contractors do not know the notification threshold
4. 4.No Health and Safety File at completion — the handover documentation does not include the HSF, which is a CDM requirement as well as a practical asset

These failures do not generally result in prosecution unless an incident occurs. But if there is a serious accident on a notifiable project where the client has not made the required appointments and the HSE notification has not been filed, the client's legal exposure is significant.

Practical steps for a prime London renovation client

Before appointing a contractor for a significant renovation, a client should:

1. 1.Confirm whether the project is notifiable — ask the contractor for their estimate of project duration and peak worker numbers
2. 2.Appoint a principal designer — confirm in writing with the architect or lead designer that they are taking on the PD role; add this to their appointment letter
3. 3.Appoint a principal contractor — confirm in writing with the main contractor that they are taking on the PC role; ensure this is in the contract
4. 4.Ensure the HSE is notified — the principal contractor typically handles this; confirm it has been done before works start
5. 5.Require a Construction Phase Plan before mobilisation — ask to see it; it does not need to be elaborate for a domestic project but it must exist
6. 6.Expect a Health and Safety File at handover — include this as a requirement in the contract

ASAAN manages CDM compliance as part of our standard project management process on all projects above the notifiable threshold. We prepare the Construction Phase Plan, manage the HSE notification, and compile the Health and Safety File for handover. If you would like to discuss CDM requirements for a planned renovation, contact us.