The CDM Regulations 2015

Chris Bowes


Conservator in hard-hat and harness with masonry battlements behind him
A conservator from Vitruvius Conservation prepares to abseil down King Alfred’s Tower, Somerset (Photo: Helen Martin, St Ann’s Gate Architects)

This article aims to review the changes to The Construction (Design and Management) Regulations 2015 (CDM) and their bearing on conservation projects.

The CDM regulations have been in place since 1994 and were updated in 2007 and again in 2015. Their aim is to improve health and safety by helping those involved in construction projects to plan work sensibly so the risks involved are managed from start to finish. At its core are the people involved and how they co-operate and co-ordinate work with others. The regulations are therefore intended to help them have the right information about the risks and how they are being managed, to help them communicate this information effectively to those who need to know, and to help them consult and engage with workers about the risks and how they are being managed.

The main differences between the 2015 CDM regulations and the previous regulations are:

  • the strengthening of client duties and the introduction of a new category, ‘domestic clients’
  • the omission of a CDM co-ordinator and the introduction of a principal designer for the planning, managing, monitoring and co-ordination of pre-construction phase health and safety (this is not a direct replacement – the range of duties carried out by the principal designer is different to those undertaken by CDM co-ordinators under CDM 2007)
  • the requirement for a principal designer and a principal contractor on all projects with more than one contractor
  • replacement of explicit requirement for duty holder competence with need for appropriate information, instruction, training and supervision
  • a change to the HSE’s notification level – now only required for projects which last more than 30 days and involve more than 20 workers simultaneously or which exceed 500 person days.

Perhaps one of the most significant changes was to remove the exemption for domestic clients. This places a duty upon them to appoint the principal designer and principal contractor, where there is more than one contractor. However, if the domestic client does not make these appointments, CDM 2015 automatically transfers the client duties to the contractor or principal contractor.

Another key change was the removal of the CDM co-ordinator role and the creation of the principal designer role. Here the intention appeared to be an attempt to integrate health and safety measures into the design process rather than having them as an adjunct.


The changes mean that more people hold duties under the CDM regulations than previously, as outlined under the headings below. Organisations or individuals can carry out the role of more than one duty holder, provided they have the skills, knowledge, experience and (if an organisation) the organisational capability to carry out those roles in a way that secures health and safety. For example, an architect can act as a designer and as a principal designer if they meet the relevant criteria.

Clients – these are the organisations or individuals for whom a construction project is carried out. They must make suitable arrangements for managing a project, including ensuring that:

  • other duty holders are appointed
  • sufficient time and resources are allocated to these duties
  • relevant information is prepared and provided to other duty holders
  • the principal designer and principal contractor carry out their duties
  • welfare facilities are provided.

Domestic clients – these are the people who have construction work carried out on their own home, or the home of a family member that is not done as part of a business, whether for profit or not. Although domestic clients are included in the scope of CDM 2015, their duties are normally transferred to the contractor on a single contractor project, or to the principal contractor on a project involving more than one contractor. However, the domestic client can choose to have a written agreement with the principal designer to carry out the client duties.

Designers – these are the people who as part of a business prepare or modify designs for a building, product or system relating to construction work. When preparing or modifying designs, designers must aim to eliminate, reduce or control foreseeable risks that may arise during construction and during the maintenance and use of a building once built. And they must also provide information to other members of the project team to help them fulfil their duties.

Principal designers – these are the designers appointed by the client in projects involving more than one contractor. They can be an organisation or an individual with sufficient knowledge, experience and ability to carry out the role, which is to plan, manage, monitor and co-ordinate health and safety in the preconstruction phase of a project. This includes:

  • identifying, eliminating or controlling foreseeable risks
  • ensuring designers carry out their duties
  • preparing and providing relevant information to other duty holders
  • providing relevant information to the principal contractor to help them plan, manage, monitor and co-ordinate health and safety in the construction phase.

Principal contractors – these are the contractors appointed by the client to coordinate the construction phase of a project which involves more than one contractor. They must plan, manage, monitor and coordinate health and safety in the construction phase of a project., including liaising with the client and principal designer, preparing the construction phase plan, and organising co-operation between contractors and coordinating their work. In addition, principal site inductions are provided, that reasonable steps are taken to prevent unauthorised access, that workers are consulted and engaged in securing their health and safety, and that welfare facilities are provided.

Contractors – these are the individuals or companies who carry out the construction work. They must plan, manage and monitor construction work under their control so that it is carried out without risks to health and safety. For projects involving more than one contractor, they must co-ordinate their activities with others in the project team, and in particular, they must comply with directions given to them by the principal designer or principal contractor. For single-contractor projects, contractors must prepare a construction phase plan.

Workers – these are the people who work for or under the control of contractors on a construction site. They must be consulted about matters which affect their health, safety and welfare, and their duties include: taking care of their own health and safety and that of others who may be affected by their actions; reporting anything they see which is likely to endanger either their own or others’ health and safety; and cooperating with their employer, fellow workers, contractors and other duty holders.


The nature of the work and the types of buildings and sites in the heritage portfolio present unique health and safety challenges. Each of the topics below could be the subject of a separate article but it is worthwhile highlighting each as being of particular relevance to heritage projects.

Access for survey, investigation and preliminary works
Most heritage projects will require high level access for surveys at some point, and falls from height are one of the major causes of fatalities in construction. Not all those who are killed or injured while working on roofs are roofers – many people accessing roofs are carrying out other tasks, such as maintenance and surveying, and they too need appropriate access arrangements.

If scaffold access is not available then a mobile elevated working platform (MEWP) will be the next best option, but these too present significant dangers. Most professionals will rely on the expertise of the MEWP hire company, but it is important to ensure that use of the machine is properly planned and managed. A risk assessment tailored to the site and the operations involved should be carried out first. This should cover, but not be limited to, the following:

  • site conditions such as confined overhead working, ground conditions and the need for outriggers, falling objects and any nearby hazards
  • the operations involved and the need for guardrails or fall-arrest systems, and precautions for handling materials and equipment
  • weather conditions.


Historic buildings contain materials and conditions such as asbestos and lead paint which present latent risks.

Commercially mined from 1870, asbestos was used for a wide range of purposes in buildings. Despite awareness of its toxicity from the early 20th century, the sale of brown and blue asbestos was only banned in the UK in 1985, while white asbestos remained legal until 1999. Consequently, there are a large number of properties with a wide range of asbestos containing materials (ACMs).

Asbestos is still the biggest industrial killer by far. It is estimated that even now an average of approximately 5,000 people die from asbestos-related diseases in the UK each year. It is commonly found in:

  • lagging around boilers or pipework
  • insulating boards, typically in gas meter cupboards or behind panel heaters
  • loose-fill insulation • as a composite in fuse boxes and switchgear
  • floor and roof tiles
  • textured coatings, such as Artex.

As a minimum, owners of buildings should commission an Asbestos Management Survey, by a specialist contractor, preferably registered with the Asbestos Removal Contractors Association (see Further Information); this comprises a visual inspection combined with sampling of suspected materials for laboratory analysis. If work is to be carried out, a refurbishment survey will be necessary, and it is mandatory that all contractors carrying out work on the site (including conservators) have received formal Asbestos Awareness Training, or a refresher course, valid within the last 12 months.

Removal of asbestos is likely to require listed building consent and confirmation should always be sought from the local authority beforehand.

Lead paint
Lead carbonates were used widely in oil-based paints until the 1960s and they are still found widely in historic buildings. It is safest to assume that any building constructed before 1970 contains some lead paint, and it is often possible to identify examples by the distinctive rectangular cracking which develops as they age.

Lead paint is usually to be found in earlier layers of paint beneath later redecorations. Any disturbance of this paint needs great caution to protect the worker and occupants, and if it must be removed, strict safety controls such as wet working and respiratory equipment should be employed. However, if the paintwork is not damaged or in poor condition, attempting to remove it might result in greater exposure to lead dust than if it were left undisturbed. Advice is available from the British Coatings Federation and the Lead Paint Safety Association (see Further Information).

Historic plaster
Lime-based plaster was reinforced with animal hair, usually from horses, cows, goats or oxen. There is a very minor risk that animal hair incorporated into plaster mixes before about 1900 (when greater controls were introduced) could be contaminated with anthrax. This is a disease of animals that can be transmitted to humans through skin lesions, inhalation or ingestion and causes skin or pulmonary infections. Generally, it is a very rare disease in the UK and the risk is very low that anthrax will be contracted from working with historic plaster.

Structural conditions
Structural conditions and risks may be subject to change so they should be reviewed regularly throughout construction. Loughborough University have produced a report, ‘Avoiding Structural Collapses in Refurbishment: A Decision Support System’, which deals with this issue (see Further Information).


The methods and materials used for conservation projects can also present risks and these need to be addressed.

Inhalable dust can cause irritation of the eyes, nose and throat, but it is the fine respirable dust which is of prime concern as a cause of serious long-term health problems, such as pneumoconiosis and silicosis.

Most serious health effects are due to regular and prolonged exposure to stone dust over past decades. It is often assumed that modern working conditions are better, but for stonemasons this may not be so. It is possible that dust exposures have gone up in the last couple of decades with the introduction of electrically powered disc cutters and polishers. It may be that silicosis and other adverse health effects among stonemasons will also rise. Proper personal protective equipment (PPE) and environmental controls need to be adopted.

Lime is a highly caustic product. Splashes of lime can burn and the dust can be highly irritating to eyes and skin. Suitable PPE should be worn at all times when working with lime. In addition to gloves, breathing apparatus/masks and goggles should be used when powdered lime dust may become air-borne and eye wash should always be available on site. This is particularly important when slaking quicklime as temperatures can reach 300ºC, and it is recommended that the slaking of quicklime and the mixing of dry powdered lime should be carried out in a well-ventilated area.

Risk assessments should be carried out prior to starting work on site and measures taken to eliminate and/or reduce the exposure to any risks identified. COSHH (Control of Substances Hazardous to Health) guidelines should be followed when using potentially harmful substances such as lime.

  A shower of sparks is created by an angle-grinder
  A craftsperson wearing safety glasses, overalls and ear protectors while preparing metalwork (Photo:

Hot works
Hot works associated with lead working present significant live and latent risks and the works need to be managed. Where there is to be any welding/hot working, only experienced personnel are to be used and site fire precautions are to be maintained in place throughout. A hot works permit regime should be established and enforced.

Work at height
Work should comply with The Work at Height Regulations 2005. The regulations apply to all work at height where there is a risk of a fall liable to cause personal injury. The regulations bring together all the existing work at height regulations and state the minimum health and safety requirements for the use of equipment. The principal contractor has a duty to ensure that work at height is properly planned, appropriately supervised and carried out in a manner that is safe. Duty holders must also ensure that those involved in working at height are competent and that the equipment they use is appropriate, well maintained and regularly inspected.

Apart from falls at roof edges there are significant risks from falls through fragile surfaces that may have been assumed to be safe, which the duty holder must also consider. Falls through fragile roofs and fragile roof lights account for almost a fifth of all the fatal accidents which result from a fall from height in the construction industry. Deaths caused by falls through fragile surfaces occur mainly to those working in the building maintenance sector when carrying out small, short-term maintenance and cleaning jobs.

On average seven people are killed each year after falling through a fragile roof or fragile roof light. Many others suffer permanent disabling injury. Surfaces that present a particular risk include old roof lights, old liner panels on built-up sheeted roofs, non-reinforced fibre cement sheets, corroded metal sheets, glass (including wired glass), rotted chipboard, slates and tiles.

Fragile roof incidents are not inevitable. They can be prevented by careful planning, using trained and experienced workers with suitable equipment and employing a high level of supervision. The HSE’s Fragile Roofs leaflet (see Further Information) includes guidance for building owners and occupiers as well as for construction businesses and their employees.


Further Information

Asbestos Removal Contractors Association

British Coatings Federation

Health & Safety Executive (HSE) asbestos information

HSE, Fragile Roofs: Safe Working Practices,

HSE/Loughborough University, ‘Avoiding Structural Collapses in Refurbishment: A Decision Support System’, 2006

Lead Paint Safety Association


The Building Conservation Directory, 2017


CHRIS BOWES founded McGregor Bowes in 2010. He is a chartered architect with over 30 years’ experience working in architectural practice. He has also been a planning supervisor, CDM co-ordinator and principal designer since 2002. He has particular expertise and interest in the care, restoration and sensitive adaptation of historic buildings.

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