Construction & Property UK-wide

If you are commissioning a construction project that meets certain thresholds, you must notify the Health and Safety Executive (HSE) before construction work begins. This notification is known as the F10 after the form used.

The F10 notification is a client duty under the Construction (Design and Management) Regulations 2015 (CDM 2015). As the client, you are legally responsible for ensuring notification happens, even if you ask the Principal Designer or Principal Contractor to submit the form on your behalf.

This guide explains when notification is required, what information you need, and how to submit your F10.

When notification is required

Not all construction projects require F10 notification. You must notify HSE if your project meets either of these thresholds:

How to calculate the thresholds

Threshold 1 - Duration and workforce:

  • 30 working days means days when construction work actually takes place - not calendar days. Weekends and bank holidays only count if work happens on those days.
  • 20 workers simultaneously means the peak number of workers on site at any single point during the project. This could be just one day - if you ever have 20 or more workers on site at the same time, you meet this part of the threshold.
  • Both conditions must be met for this threshold to trigger notification.

Threshold 2 - Person-days:

  • Calculate the total number of worker-days across the entire project.
  • Example: 10 workers for 50 days = 500 person-days (notifiable).
  • Example: 50 workers for 10 days = 500 person-days (notifiable).
  • Example: 4 workers for 100 days = 400 person-days (not notifiable on this threshold alone).

When in doubt, notify. There is no penalty for notifying a project that turns out not to meet the thresholds. HSE prefers over-notification to under-notification. Failing to notify when required is a criminal offence.

Who must notify

The client has the legal duty to notify HSE. If you are having construction work done for you, you are the client.

You may ask the Principal Designer or Principal Contractor to submit the F10 on your behalf - this is common practice. However, you remain legally responsible for ensuring notification happens before construction begins.

If you delegate the task, confirm in writing who is responsible for submitting the notification and follow up to ensure it has been done. Keep a copy of the submitted notification or HSE's acknowledgement.

Domestic clients

If you are a domestic client (commissioning work on your own home for personal use, not as part of a business), the notification duty transfers to:

  • The contractor (for single-contractor projects)
  • The principal contractor (for multi-contractor projects)

However, you should still check that notification has been submitted if your project is large enough to be notifiable.

When to notify

You must notify HSE as soon as practicable before the construction phase begins.

"As soon as practicable" means as early as you reasonably can once you know the project is notifiable. This is typically during the design or pre-construction phase, when you have enough information to complete the form.

Do not start construction work until notification has been submitted. Beginning construction on a notifiable project without notification is a criminal offence.

If you realise mid-project that you should have notified (for example, the project scope has grown), submit notification immediately. Late notification is better than no notification, though you may still face enforcement action for the period before notification.

Information required in the F10

CDM 2015 Schedule 1 specifies 15 particulars that must be included in the F10 notification. You will need to gather this information before submitting:

Information you need to gather

Before starting the online form, collect:

  • Site address: Full postal address or precise location description if no postal address exists
  • Local authority: The council area where the site is located
  • Project description: Brief summary of what the construction work involves
  • Client details: Your name, address, telephone, and email
  • Principal Designer details: Name, address, telephone, email (if appointed)
  • Principal Contractor details: Name, address, telephone, email (if appointed)
  • Planned start date: When construction work is expected to begin
  • Planned duration: How long the construction phase is expected to last
  • Time allocated for completion: The overall time you have allowed for the project
  • Maximum workers expected: Estimated peak number of workers on site
  • Number of contractors: How many different contractors will work on the project
  • Names of appointed contractors and designers: Those already appointed at time of notification

If some appointments have not yet been made when you submit notification, you can update the F10 later when appointments are finalised.

How to submit F10 notification

The easiest way to notify HSE is online. The online form takes approximately 10-15 minutes to complete if you have gathered the required information in advance.

  1. Go to the HSE F10 notification page

    Visit hse.gov.uk/forms/notification/f10.htm and select 'Start the F10 notification'.

  2. Enter project details

    Complete all required fields about the site location, project description, and planned dates. Be as accurate as possible - you can update details later if they change.

  3. Enter duty holder details

    Provide contact information for the client, Principal Designer (if appointed), and Principal Contractor (if appointed). Include name, address, telephone, and email for each.

  4. Provide workforce estimates

    Enter the estimated maximum number of workers and planned number of contractors. These are estimates - you are not held to exact figures.

  5. Complete the client declaration

    The form includes a declaration that you (the client) are aware of your duties under CDM 2015. Tick to confirm you understand your legal obligations.

  6. Submit and save the acknowledgement

    Once submitted, you will receive an acknowledgement from HSE. Save or print this - you will need it for site display.

Displaying the notification on site

Once you have submitted the F10, you must display the notification (or HSE's acknowledgement) on the construction site where it can be read by any worker engaged in the construction work.

Typical display locations include:

  • The site office
  • The welfare facilities
  • The main site entrance
  • A notice board visible to all workers

The notification must remain displayed throughout the construction phase. If you update the notification, display the updated version.

The Principal Contractor is typically responsible for ensuring the notification is displayed, but as client, you should verify this has been done.

Updating the notification

CDM 2015 requires the F10 to be updated periodically as necessary. You should update the notification when there are significant changes to the information provided.

Examples of changes requiring update:

  • Change of Principal Designer or Principal Contractor
  • Significant change to planned start date or duration
  • Substantial increase in maximum number of workers
  • Change of client (for example, if the property is sold during construction)
  • Major change to the scope of works

Minor changes (such as small adjustments to timescales or minor variations in workforce numbers) do not typically require updates.

To update an existing F10, contact HSE or submit a new notification referencing the original. The updated notification should then be displayed on site.

Where to notify for special projects

Most construction projects are notified to HSE. However, certain specialist projects must be notified to different authorities:

Standard construction projects
Health and Safety Executive (HSE) via online F10 form
Railway transport work
Office of Rail and Road (ORR)
Nuclear sites
Office for Nuclear Regulation (ONR)

If your project involves work on railway infrastructure or nuclear facilities, check the relevant regulator's website for their notification requirements. Do not use the standard HSE F10 form for these projects.

Penalties for not notifying

Failing to notify a notifiable construction project is a criminal offence under CDM 2015. The Health and Safety Executive can prosecute clients who breach their notification duties.

HSE may discover non-notification through:

  • Routine site inspections
  • Investigation following an accident or complaint
  • Cross-referencing planning applications with notifications
  • Information from other duty holders or workers

"I didn't know notification was required" is not a defence. Clients are expected to understand their CDM duties before commissioning construction work.

F10 notification checklist

Before construction begins, confirm you have:

  1. Calculated whether your project is notifiable

    Check against both thresholds: 30+ working days with 20+ simultaneous workers, OR 500+ person-days. If either threshold is met, you must notify.

  2. Gathered all required information

    Site address, local authority, project description, all duty holder contact details, planned dates, workforce estimates.

  3. Submitted F10 notification online

    Complete the HSE online form at hse.gov.uk/forms/notification/f10.htm before construction begins.

  4. Saved the acknowledgement

    Keep a copy of the submitted notification or HSE's acknowledgement for your records.

  5. Arranged site display

    Ensure the notification or acknowledgement will be displayed on site where workers can read it throughout construction.

  6. Set up a process for updates

    Know who will update the F10 if significant details change, and ensure updated notifications are displayed on site.

Related guidance

F10 notification is just one of many client duties under CDM 2015. For comprehensive guidance on all your obligations as a construction client, see: