CDM regulations and what they mean for your building project

If you are having building work done on your property, whether that is an extension, a conversion, a new build or even a significant internal alteration, there is a set of regulations called CDM that applies to your project. Most homeowners have never heard of them, most builders know they exist but are hazy on the detail, and the result is that the legal duties CDM places on you as the person paying for the work often go completely unmentioned until something goes wrong.

CDM stands for the Construction (Design and Management) Regulations 2015, and they have been in force since April 2015. They replaced the earlier CDM 2007 regulations and made some important changes, the biggest of which is that CDM 2015 applies to all construction projects regardless of size. The old regulations had exemptions for smaller domestic projects. Those exemptions are gone. If you are having a builder on your property doing construction work, CDM applies to you.

That sounds more alarming than it is in practice, and the point of this article is to explain what it actually means rather than leaving you to assume the worst.

CDM 2015 defines several duty holders, and which ones apply to your project depends on how many contractors are involved and how long the work takes. The duty holders are the client, the designer, the principal designer, the contractor, the principal contractor and workers.

As the person commissioning and paying for the work, you are the client. That is true whether you are a commercial developer building fifty houses or a homeowner having a single-storey extension put on the back of your house in Derbyshire. The regulations do not distinguish between the two.

The designer is whoever prepares or modifies a design for a building, a product or a system relating to construction work. If you have appointed an architectural designer to produce your planning and building regulation drawings, they are a designer under CDM. If the structural engineer produces calculations and details, they are a designer too.

The contractor is the person or company doing the physical building work. If there is more than one contractor working on the project at any time, which is common on anything beyond a very small project because you might have a builder, an electrician, a plumber and a roofer all working at different stages, then CDM requires a principal designer and a principal contractor to be appointed. The principal designer coordinates the design work and makes sure health and safety is considered from the start. The principal contractor manages the construction phase and coordinates between the different contractors on site.

For projects with only one contractor, the duties of the principal designer and principal contractor are not formally required, but the client's duties and the designer's duties still apply in full.

This is the part that surprises most homeowners. Under CDM 2015 you have legal duties even though you are not doing any of the building work yourself. The regulations assume that you, as the person paying, have influence over how the project is run, and they place responsibilities on you accordingly.

Your main duties are to make suitable arrangements for managing the project, which in practice means appointing the right people with the right skills and experience. You need to make sure that enough time and resources are allocated to each phase of the project, and you need to make sure that relevant information about the site is provided to the designers and contractors. If there is asbestos in the building, or if there are underground services running through the site, or if there is contaminated ground, that information needs to be shared with the people doing the work.

You also need to make sure that a construction phase plan is in place before work starts. For a project with a principal contractor, they prepare the plan. For a single-contractor project, the contractor prepares it. But the duty to make sure it exists sits with you as the client. In practice what this means is that you ask the question. Has the construction phase plan been prepared? If the builder looks at you blankly, that is a problem, and it is better to find that out before work starts than after an accident on site.

For domestic clients, and this is a specific category under the regulations meaning a person who lives or will live in the premises where the work is being done, the regulations recognise that you probably do not know how to manage a construction project and are not expected to. Where a domestic client has not appointed a principal designer, the designer or the principal contractor takes on the client's duties automatically. So in practice, if you appoint an architectural designer and a builder, the system works without you having to become a project manager overnight. But it is still worth knowing what the duties are, because they are your duties in law even if someone else is discharging them on your behalf, and if nobody is discharging them at all then you are the one left holding them.

The 2007 regulations had a role called the CDM Coordinator, which was an external appointment required on notifiable projects. CDM 2015 abolished that role and replaced it with the principal designer, who is already on the project team rather than being an additional appointment from outside. This was a significant change because the CDM Coordinator was often seen as an administrative role bolted onto the project rather than being integrated into the design process, and the principal designer model works better in practice because the person coordinating health and safety is also the person making the design decisions that affect it.

The other major change was removing the notification threshold. Under CDM 2007, projects only needed to be notified to the Health and Safety Executive if they lasted more than 30 days or involved more than 500 person-days of work. Under CDM 2015, notification is required for any project lasting longer than 30 working days with more than 20 workers on site at any one time, or exceeding 500 person-days of construction work. Most domestic projects fall below this threshold, but extensions on larger properties and certainly new builds often do not, and notification is the client's duty.

The removal of the domestic exemption was the change that affected homeowners most directly. Before April 2015, if you were having work done on your own home the CDM regulations essentially did not apply to you. After April 2015, they do. The intent was not to burden homeowners with paperwork but to make sure that safety standards applied consistently regardless of who was paying for the work, because a bricklayer falling off scaffolding is just as injured whether the building is a warehouse or a kitchen extension.

If you are extending your house or converting a garage or a loft, and you have appointed an architectural designer to handle the planning and building regulation approvals and a builder to do the work, then in practice CDM means the following.

Your architectural designer considers health and safety at the design stage. That means thinking about things like how the building will be maintained once it is finished, whether window cleaning requires working at height, whether the design creates risks during construction that could be avoided with a different approach. This is not separate from the design process, it is part of it, and a competent designer does it as a matter of course without you needing to ask.

Your builder prepares a construction phase plan before work starts. For a straightforward domestic project this does not need to be a lengthy document. It needs to cover how the work will be managed, the arrangements for health and safety on site, and how risks will be controlled. If your builder cannot produce one, that tells you something worth knowing about whether they are the right builder for your project.

And you, as the client, satisfy your duties by appointing competent people, making sure they have the information they need about the property, and checking that the construction phase plan is in place before work starts. That is it. You do not need to inspect the scaffolding or write risk assessments. You need to have asked the right questions and appointed the right people.

One practical thing that trips people up is the pre-construction information that CDM requires the client to provide. This is information about the site and the existing building that might affect health and safety during the work. If there is asbestos, if the building has unusual structural features, if there are overhead power lines or underground drainage running through the area where the builder needs to dig, that information needs to be passed on.

You are not expected to commission surveys you did not already have. But if you know about something, or if it came up in a survey report when you bought the property, it needs to be shared. Holding back information that a contractor needed to work safely is exactly the kind of thing that turns an accident into a legal problem for the client.

If you are planning a project and you want to make sure the CDM duties are handled properly from the start, get in touch with us on 07773 899 597 or email abds@abds.biz. We handle the design coordination as part of the service and can make sure everything is in place before your builder starts on site.