Construction compliance guide

What Is a Health and Safety File in Construction? Complete UK Guide

Everything you need to know about the CDM 2015 health and safety file — what goes in it, who creates it, when to hand it over, and why it matters long after the project is finished.

Nicola Dobbie·Founder, The Site Book

TL;DR

• The health and safety file is a CDM 2015 requirement for projects with more than one contractor.
• It is a permanent record of information needed for future maintenance, alteration, or demolition of the building.
• The principal designer creates it; the client keeps it for the life of the building.
• It is not the same as a construction phase plan — the CPP is for during the build, the H&S file is for afterwards.
• Contents include as-built drawings, residual hazards, structural details, and maintenance information.

What is a health and safety file?

A health and safety file is a permanent collection of information about a building or structure that anyone carrying out future construction work will need. It records how the building was built, what materials were used, where the hidden hazards are, and what maintenance is needed to keep it safe.

Think of it as the building’s medical record. Just as a doctor needs your history before treating you, a builder working on a building in the future needs to know what is behind the walls, under the floors, and above the ceilings before they start disturbing anything. The health and safety file provides that information.

The concept was first introduced under the original CDM Regulations in 1994. The current requirement comes from Regulation 12(5) of the Construction (Design and Management) Regulations 2015 (CDM 2015). The HSE provides specific guidance in their CDM 2015 health and safety file guidance.

What does the law say?

CDM 2015 Regulation 12(5) states that the principal designer must prepare a health and safety file for the project. The file must contain information relating to the project that is likely to be needed during any subsequent project to ensure the health and safety of any person. For a full overview of CDM 2015, see our What is CDM? guide.

The key legal duties are:

The principal designer must prepare, review, update, and revise the file during the project.
The principal designer must pass the file to the client at the end of the project (or to the principal contractor if the principal designer’s appointment ends first).
The client must keep the file available for inspection by anyone who needs it for future construction work.
If the property is sold or transferred, the file must go with it.
The file must be updated whenever further construction work is carried out on the building.

There is no prescribed format. The regulations do not say it must be a ring binder, a PDF, or a cloud-based system. What matters is that it exists, it contains the right information, and it is accessible when needed.

What goes in a health and safety file?

CDM 2015 does not provide an exhaustive list, but the HSE guidance and Regulation 12(5) make clear that the file should contain information about the current project that is likely to be needed to ensure health and safety during any subsequent work. In practice, this means:

As-built drawings and plans

Accurate drawings showing the building as it was actually constructed, not just the original design drawings. These should show the location of structural elements, foundations, drainage, services (gas, water, electricity, data), fire protection systems, and any features that differ from the original design.

Residual hazards and risks

Information about any hazards that remain in the building after construction is complete. This includes asbestos-containing materials, contaminated land beneath the foundations, fragile roof materials, areas where work at height is required for maintenance, and any other hazard that a future worker needs to know about.

Structural details

Information about the structural design, including load-bearing walls, steelwork connections, pre-stressed or post-tensioned concrete elements, and any structural limitations. Anyone working on the building in the future needs to know which walls they cannot remove and what loads the structure can bear.

Services and utilities

Location and routing of all services — gas, water, electricity, telecoms, drainage, and any specialist systems. This is critical safety information. Builders have been killed by accidentally cutting into live services that were not shown on any available drawings.

Maintenance information

Details of any equipment or features that require ongoing maintenance, how that maintenance should be carried out safely, and what access provisions have been made. For example: how to safely access the roof for gutter cleaning, what PPE is needed for maintaining mechanical plant, or how to isolate electrical systems for inspection.

Materials and products used

Information about key materials used in the construction, particularly those that might present hazards during future work — treated timber, specialist coatings, insulation types, waterproofing membranes, and any products with specific handling or disposal requirements.

The file should only contain information that is useful for future health and safety purposes. It is not a general project archive — do not fill it with every email, every order confirmation, or every site photograph. Keep it focused and relevant.

Who creates and maintains the health and safety file?

The principal designer is the dutyholder responsible for creating the health and safety file. On most commercial projects, the principal designer is the architect or lead design consultancy. On smaller projects, it might be a structural engineer or even the client’s agent.

However, the principal designer cannot create the file alone. They need information from other parties, particularly the principal contractor and other designers and contractors. This means:

Contractors must provide as-built information, product data sheets, and details of any changes made during construction that differ from the original design.
Specialist subcontractors (steelwork fabricators, M&E installers, piling contractors) must provide relevant technical information about their installations.
The principal contractor must cooperate with the principal designer in gathering this information and must take over the file if the principal designer’s appointment ends before the project is complete.
Designers must provide information about residual design risks that will affect future work on the building.

If you are a builder working as a subcontractor on a project, you will likely be asked to provide information for the health and safety file. This is a legal expectation — cooperate promptly and provide accurate, useful information.

When do you hand it over?

The health and safety file must be handed to the client at the end of the project. In practice, “the end of the project” usually means practical completion — when the building is ready for occupation or use.

The principal designer should not wait until the last day to start compiling the file. The file should be built up throughout the project as information becomes available. Waiting until handover to gather everything typically results in missing information, because subcontractors have left site and moved on.

If the principal designer’s appointment ends before the project is finished (which sometimes happens on phased projects or when there is a change of designer), they must pass the file to the principal contractor. The principal contractor then takes on the duty to maintain and update the file until it can be handed to the client at the end of the project.

On some projects, particularly larger ones, the file may be handed over in stages — for example, when individual buildings or phases are completed. The important thing is that the client receives the relevant information before they take responsibility for the completed structure.

How does it differ from a construction phase plan?

This is one of the most common areas of confusion in CDM 2015. The construction phase plan (CPP) and the health and safety file serve entirely different purposes:

Construction phase plan (CPP)

A live document used during the construction phase to manage health and safety on site. It covers the arrangements for managing the project, the specific risks of the work, and the control measures being used. The principal contractor creates and maintains the CPP. It is a working document that changes as the project progresses.

Health and safety file

A permanent record for the future. It contains information about the completed building that will be needed by anyone carrying out subsequent construction work, maintenance, cleaning, alteration, or demolition. The principal designer creates it. It stays with the building for its entire life.

A simple way to remember: the CPP asks “how do we build it safely?” and the H&S file asks “how do we work on it safely in the future?” Both are important, but they are different documents with different purposes, different authors, and different audiences.

What happens to the file after the project?

Once the client receives the health and safety file, it becomes their responsibility. CDM 2015 places clear duties on the client:

Keep the file available for inspection by anyone carrying out future construction work on the building.
Ensure the file is updated whenever further construction work is done — each new project should add its relevant information to the existing file.
Pass the file on if the building is sold, leased, or otherwise transferred to a new owner.
Make the file available to the principal designer and principal contractor of any future project, so they can use it to plan and manage the work safely.

In reality, many health and safety files are handed over in a ring binder, put on a shelf, and never looked at again until the next major refurbishment. This is a wasted opportunity. A good H&S file saves time and money on future projects because designers and contractors do not have to investigate what is behind every wall or under every floor from scratch.

Do domestic projects need a health and safety file?

If a domestic project involves more than one contractor, CDM 2015 applies in full, which means a health and safety file is required. However, on domestic projects, the client’s duties (including keeping the H&S file) normally transfer to the contractor or principal contractor unless the domestic client chooses to take them on. For more detail on how CDM applies to homeowners, see our domestic client CDM guide.

For a typical domestic extension or loft conversion with multiple trades involved, you should produce a simple health and safety file and hand it to the homeowner at the end of the project. Explain what it is and why they should keep it. Include the key items — as-built drawings, structural engineer’s details, information about materials used, and any residual hazards (such as the location of buried drainage or the presence of a steel beam above a new opening).

Even on single-contractor domestic jobs where it is not strictly required, providing a basic H&S file is good practice. It demonstrates professionalism, protects future tradespeople, and adds value for the homeowner. It does not need to be elaborate — a folder with the structural calculations, service locations, and a note about any hazards is usually sufficient.

Health and safety file contents checklist

Use this checklist as a starting point. Not every item will apply to every project, and some projects will require additional information not listed here. The key question to ask for each piece of information is: “Would someone carrying out future work on this building need this to do the job safely?”

A brief description of the work carried out, including the design principles and materials used.
As-built drawings and site plans showing the structure, foundations, drainage, and services as actually constructed.
Structural engineer’s calculations and details, including load-bearing elements and any design limitations.
Details of all services and utilities: routing, connection points, isolation procedures, and any hazardous energy sources.
Information about residual hazards: asbestos, contaminated ground, fragile materials, confined spaces, live services, or any other hazard that is not immediately obvious.
Maintenance procedures for any installed equipment (lifts, HVAC systems, fire suppression, lightning protection, etc.) including safe access requirements.
Details of materials used that may be hazardous during future work: treated timber, specialist insulation, lead-based coatings, or composite materials.
Fire safety information: fire compartmentation details, fire-stopping locations, smoke ventilation systems.
Waterproofing and tanking details where applicable.
Any specialist information from subcontractors (piling records, steelwork fabrication details, cladding system specifications).
Manufacturer’s operation and maintenance manuals for installed equipment.
Certificates and test results: structural, electrical, gas, fire alarm, lightning protection.

Common problems and how to avoid them

Health and safety files are one of the most neglected aspects of CDM 2015. Here are the problems that come up most often:

Left until the last minute

If you wait until handover to start compiling the file, you will struggle to get information from subcontractors who have already left site. Start building the file from day one. Request as-built information and product data as each phase of work is completed, not after the scaffolding comes down.

Too much irrelevant information

A health and safety file crammed with every site diary entry, every email, and every delivery note is useless. Future users need to find the relevant information quickly. Keep it focused on information that is genuinely needed for future health and safety purposes.

Missing as-built drawings

The original design drawings are not the same as as-built drawings. Services get rerouted, structural details change, and design amendments happen during construction. The file must show the building as it was actually built. Insist on marked-up or redrawn as-built drawings before accepting the file as complete.

Not explaining residual hazards clearly

Simply listing "asbestos" is not helpful. Where exactly is it? What type? What condition is it in? What should someone do before disturbing it? The file should be written so that a competent builder who has never seen the building before can understand the risks.

Lost after handover

Paper files get lost, misfiled, or thrown away during office moves. Digital files stored on a single computer are vulnerable to hardware failure. Use a cloud-based system or at minimum provide copies in multiple formats and locations. Advise the client on their duty to keep the file and pass it on.

Digital vs. paper: which format is better?

CDM 2015 does not prescribe a format, but digital files are almost always the better choice. A digital health and safety file is searchable, shareable, and far less likely to be lost than a ring binder in a filing cabinet. Cloud storage means it is accessible from anywhere and can be shared with future designers, contractors, and building owners instantly.

If you do provide a paper file, consider also providing a digital copy on a USB drive or via a shared cloud folder. Make sure all drawings are legible at the printed size — an A0 drawing reduced to A4 is often unreadable. For digital files, use widely accessible formats like PDF for documents and DWG or PDF for drawings.

Using a project management tool like The Site Book means all your project documents — RAMS, drawings, safety data sheets, certificates — are already stored in one place. When it comes to compiling the health and safety file, you have everything to hand rather than chasing subcontractors for information they should have provided months ago.

Practical tips for builders

Whether you are creating a health and safety file or contributing to one, these practical tips will help you get it right:

Take photographs of services, structural elements, and hidden features before they are covered up. A photo of drainage before backfilling is worth a thousand words.
Record any deviations from the design drawings as they happen. Do not rely on memory six months later when the principal designer asks for as-built information.
Use clear, plain English in all descriptions. The person reading the file in 20 years’ time will not know the project or the people involved. Avoid jargon, abbreviations, and references to conversations or decisions that are not recorded in writing.
Include contact details for specialist installers where ongoing maintenance is required (e.g. the company that installed the fire suppression system or the structural engineer who designed the steelwork).
If you are working on an existing building and there is already a health and safety file, add your project’s information to it rather than creating a separate document. The file should grow with the building.
Make sure any drawings or documents you provide are clearly labelled with the project name, date, author, and revision number.

Frequently asked questions

Common questions about health and safety files in construction.

Is a health and safety file required for every construction project?

Under CDM 2015, a health and safety file is required for every project that involves more than one contractor. For projects with only one contractor, the regulations do not specifically require a health and safety file, although it is still considered good practice to compile one — especially for projects that alter the structure of a building or introduce residual hazards that future workers or occupants need to know about. If a principal designer has been appointed, they must prepare or update the health and safety file. The file must contain information likely to be needed during any subsequent construction work, including cleaning, maintenance, alteration, or demolition.

Who is responsible for creating the health and safety file?

The principal designer is responsible for preparing, reviewing, updating, and revising the health and safety file during the construction phase. If no principal designer has been appointed (which can happen on projects with only one contractor), the responsibility falls on the designer in a position to coordinate health and safety matters. Once the project is complete, the principal designer must pass the file to the client. If the principal designer’s appointment finishes before the project is complete, they must pass the file to the principal contractor, who then takes on responsibility for maintaining it until handover to the client.

What is the difference between a health and safety file and a construction phase plan?

They serve completely different purposes. A construction phase plan (CPP) is a live working document used during the construction phase to manage health and safety risks on site. It covers how the project will be managed, the specific risks, and the arrangements for controlling them. The health and safety file, by contrast, is a permanent record intended for future use — it contains information that anyone carrying out subsequent work on the building will need. Think of the CPP as the instruction manual for building it safely now, and the H&S file as the maintenance manual for working on it safely in the future. The CPP is discarded or archived after the project; the H&S file stays with the building for its entire life.

What happens to the health and safety file after handover?

Once the client receives the health and safety file, they must keep it available for inspection by anyone who needs it for future construction work, maintenance, or demolition. If the building is sold, the file must be passed to the new owner. If the client is a landlord or property management company, they must ensure the file is accessible. There is no expiry date — the file must be kept for the life of the building. The client is also responsible for ensuring the file is updated whenever further construction work is carried out on the building. In practice, many H&S files are lost or forgotten after handover, which creates problems for future projects.

Can a health and safety file be digital?

Yes, absolutely. CDM 2015 does not specify a format. A digital health and safety file is often preferable because it is easier to search, share, update, and store securely. It also eliminates the problem of paper files being lost, damaged, or locked away in a filing cabinet where nobody can find them. Cloud-based storage ensures the file is accessible to anyone who needs it, including future contractors, designers, and building owners. The key requirement is that the file is kept available for inspection — a digital format meets this requirement as long as it is accessible and can be produced when needed.

What if the previous health and safety file has been lost?

This is unfortunately common, especially with older buildings. If you are working on a building and the existing H&S file cannot be found, you should make every effort to gather the information it should contain — check with the building owner, previous designers, local authority building control records, and any available as-built documentation. For the current project, the principal designer must create a new health and safety file that captures all relevant information about the work being carried out. Going forward, the client should be advised of their duty to keep the file safe and pass it on with any future sale of the property.

How The Site Book helps

• All project documents stored in one place — RAMS, drawings, certificates, and safety data sheets.
• Easy handover — share the complete project file with the client in one click.
• Compliance dashboard shows the status of every document, so nothing gets missed.
• Cloud-based storage means the file is always accessible and never lost.

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