CDM 2015 Core · Mandatory · Pre-Construction
F10 Notification to HSE
The F10 notification formally notifies the Health and Safety Executive that a construction project is about to commence. It is required for projects lasting longer than 30 working days with more than 20 workers, or exceeding 500 person-days. The notification must be submitted before the construction phase begins and displayed on site.
Last reviewed: 29 March 2026 — This guide reflects UK law as of this date. CDM 2015 Reg 6 remains current with no amendments enacted as of 29 March 2026. Next scheduled review: 29 March 2027.
| Legal basis | CDM 2015 Regulation 6 and Schedule 1 — Notification |
| When required | ONLY on notifiable projects — see thresholds below. NOT required on all construction projects. |
| Who submits | The client. Can be delegated to PD, PC, or agent — but client remains legally responsible for accuracy. |
| When to submit | As soon as practicable BEFORE the construction phase begins |
| How to submit | Online only — hse.gov.uk/forms/notification/f10.htm. No paper forms or email accepted. |
| Must be displayed | An up-to-date copy must be displayed on site in comprehensible form in the site office |
| Must be updated | If key project details change — particularly PC, PD, start date, or significant scope changes |
| Enforcing authority | HSE (standard projects) / ORR (railway) / ONR (nuclear) |
1. What Is an F10 Notification?
An F10 is a formal written notification submitted to the Health and Safety Executive (HSE) before certain construction projects begin. It tells the HSE that a project meeting specific size thresholds is about to start — who is involved, where it is, how long it will take, and how many people will be working on it.
The HSE uses F10 notifications to target its inspection and enforcement resources towards the larger, higher-risk projects where its intervention is most likely to prevent harm. Notified projects are more likely to receive a site visit.
CDM 2015 Regulation 6(2) states the legal requirement:
“Where a project is notifiable, the client must give notice in writing to the Executive as soon as is practicable before the construction phase begins.”— CDM 2015 Regulation 6(2)
Critical distinction — notification is NOT the same as CDM compliance
Submitting an F10 is not the same as complying with CDM 2015. The notification simply informs the HSE that the project is happening. All other CDM duties — PCIP, CPP, PD and PC appointments, H&S File — continue regardless of whether an F10 has been submitted. The F10 is one small administrative step within a larger compliance framework.
2. Which Projects Are Notifiable?
Only projects that meet one or both of the thresholds in CDM 2015 Regulation 6(1) are notifiable. Most construction projects — particularly smaller commercial projects and most domestic work — will not meet either threshold.
| Threshold A | Threshold B |
|---|---|
| More than 30 working days AND more than 20 workers simultaneously. Both conditions must be met. | More than 500 person-days (total across all workers). Either threshold alone triggers notification. |
Breaking down the thresholds precisely:
- Threshold A: The project must last more than 30 working days AND have more than 20 workers on site at the same time at any point. Both conditions must be true simultaneously. A project lasting 60 working days but never exceeding 15 workers does not meet Threshold A.
- Threshold B: The total number of person-days exceeds 500. A person-day is one worker working for one day. This threshold is met by multiplying the average number of workers by the number of working days. Either Threshold A or Threshold B alone is sufficient to make the project notifiable.
- Working day definition: A working day means any day on which construction work takes place. Weekends count if work is being carried out. Bank holidays count if work is being carried out. Only days where no construction activity at all occurs are excluded.
Person-day calculation examples:
- 10 workers for 60 days = 600 person-days — notifiable under Threshold B
- 5 workers for 80 days = 400 person-days — not notifiable under Threshold B (but check Threshold A)
- 25 workers for 35 days = 875 person-days — notifiable under both thresholds
The threshold interaction — a common source of confusion
Contractors frequently state the notification threshold incorrectly as ‘30 days and 20 workers’ without appreciating that this is only one of two independent thresholds, and that Threshold B operates entirely separately. A project with 8 workers for 70 days (560 person-days) is notifiable under Threshold B alone — even though it never has more than 20 workers on site at any point. Conversely, a short-duration project with a large workforce can meet Threshold A without reaching 500 person-days.
Projects can become notifiable mid-works. If scope changes, programme extensions, or additional workforce mean the project now meets either threshold, the client must submit an F10 notification at that point. The duty arises as soon as it becomes apparent the thresholds will be met — not only at the start of the project.
3. Who Is Responsible for Submitting It?
The legal duty to notify rests with the client under CDM 2015 Regulation 6. In practice, this means the person or organisation for whom the construction project is being carried out. The client may delegate the practical task of submitting the form — but the legal responsibility for ensuring it is submitted, and that the information it contains is accurate, remains with the client at all times.
| Scenario | Description |
|---|---|
| Commercial clients | The client holds the legal duty to submit the F10. This is typically a developer, property company, local authority, or corporate entity. The duty cannot be transferred — only the practical task of completing the online form can be delegated. |
| Domestic clients | CDM 2015 Regulation 7 transfers the domestic client's duties to the contractor (single contractor) or principal contractor (multiple contractors). This means the contractor or PC inherits the notification duty on domestic projects where the thresholds are met. |
| Delegating submission | The client can ask the Principal Designer, Principal Contractor, or any agent to complete and submit the online form on their behalf. This is common in practice. However, the client remains legally responsible for accuracy and timeliness. If the PD submits incorrect information, the client is still liable. |
| All duty holders' shared responsibility | While only the client has the legal duty to notify, all duty holders have a general duty to cooperate under CDM 2015 Regulation 8. If a contractor knows a project is notifiable and the client has not submitted an F10, the contractor should raise this. Ignoring it does not absolve other parties. |
4. When Must It Be Submitted?
The F10 must be submitted ‘as soon as practicable before the construction phase begins.’
- Before construction starts: The notification must be submitted before any construction work begins on site. This includes enabling works, demolition, site clearance, and any physical work that falls within the CDM definition of construction.
- As soon as practicable: This means as soon as the client reasonably knows the project will be notifiable. Waiting until the day before works start, when the information was available weeks earlier, would not satisfy the ‘as soon as practicable’ requirement.
- Not all information needs to be final: The HSE accepts that some details — particularly the PC appointment or exact start date — may not be confirmed when the initial notification is submitted. The F10 can and should be updated as information is confirmed.
- No specific number of days in advance: CDM 2015 does not prescribe a fixed number of days before start. The previous regulations (CDM 2007) did, but this requirement was removed. The test is ‘as soon as practicable’ — not a fixed notice period.
Late notification is still better than no notification
If construction has already started and no F10 has been submitted, the client should submit it immediately. The HSE would rather receive a late notification than no notification at all. A late F10 is a regulatory breach — but failing to notify altogether is a more serious breach and removes the project entirely from the HSE's awareness.
5. What Information Is Required?
Schedule 1 of CDM 2015 sets out exactly what the F10 notification must contain.
| # | Required Information | Notes |
|---|---|---|
| 1 | Date of forwarding | Date the notification is submitted to the HSE |
| 2 | Address of the construction site | Full postal address or description of location if no postal address exists |
| 3 | Local authority area | The local authority in whose area the site is located |
| 4 | Brief description of the project | Nature and purpose of the works — sufficient for the HSE to understand the type of project |
| 5 | Name and address of the client | The person or organisation for whom the project is being carried out |
| 6 | Name and address of the Principal Designer | If not yet appointed, state this — but appointment must be made before the construction phase begins |
| 7 | Name and address of the Principal Contractor | If not yet appointed, state this — but appointment must be made before the construction phase begins |
| 8 | Date planned for start of the construction phase | Best estimate if not confirmed — must be updated if it changes significantly |
| 9 | Planned duration of the construction phase | In weeks — best estimate at the time of notification |
| 10 | Estimated maximum number of workers on site at any one time | Peak workforce — relevant to Threshold A |
| 11 | Planned number of contractors on site | Total number of contractor organisations, not individual workers |
| 12 | Name and address of contractors already appointed | Any contractors already engaged at the time of notification |
| 13 | Name and address of contractors already chosen but not yet appointed | Contractors selected but not formally appointed |
| 14 | Whether the project involves demolition | Yes/No — demolition triggers additional regulatory requirements |
Partial information at initial submission
It is common — and acceptable — to submit the F10 before all information is confirmed. The PD and PC may not yet be appointed. The exact start date may not be fixed. The number of contractors may not be finalised. The HSE expects the initial notification to be submitted with whatever information is available, and for the notification to be updated as details are confirmed. The key obligation is to notify early — not to wait until every detail is finalised.
6. How to Submit the F10
The HSE only accepts F10 notifications submitted online.
| Detail | Information |
|---|---|
| Portal URL | hse.gov.uk/forms/notification/f10.htm |
| Submission method | Online form only. No paper forms, no email submissions, no postal submissions. |
| Confirmation | The portal generates a confirmation. Save this as your record of notification. |
| Displaying on site | An up-to-date copy of the F10 must be displayed in the site office or other prominent location where it can be read by anyone working on the project. |
| Updating | If key details change — PC, PD, start date, scope — resubmit the F10 via the same online portal. There is no separate update form. |
| Single-contractor projects | If a project meets the notification thresholds but has only one contractor, it is still notifiable. The PC and PD fields on the form are not applicable in this scenario — there is no PC or PD on a single-contractor project. |
| Northern Ireland | CDM 2015 does not apply in Northern Ireland. Northern Ireland has separate construction health and safety regulations administered by HSENI. |
Notifying authorities by project type
| Project Type | Notifying Authority | Notes |
|---|---|---|
| Standard construction | HSE | The vast majority of projects. Submit via the HSE online portal. |
| Railway | ORR (Office of Rail and Road) | Construction work on or adjacent to the railway is regulated by the ORR, not the HSE. |
| Nuclear | ONR (Office for Nuclear Regulation) | Construction on licensed nuclear sites is regulated by the ONR. |
| Defence | HSE | MOD construction projects are notified to the HSE in the normal way, unless on a nuclear-licensed site. |
7. What Notification Does — and Does Not — Mean
This is the most important nuance of the F10. Notification tells the HSE the project exists. It does not, by itself, create or remove any CDM duty. This is a significant change from the previous regulations.
Under CDM 2007 — notifiability triggered additional duties
Under the previous CDM 2007 regulations, whether a project was notifiable directly determined which duties applied. Notifiable projects required a CDM Coordinator, a written Construction Phase Plan, and a Health and Safety File. Non-notifiable projects had significantly reduced requirements. The F10 notification was the gateway that triggered these additional obligations.
Under CDM 2015 — they are completely decoupled
CDM 2015 fundamentally changed this. The duties that apply to a project are now determined by the number of contractors, not by whether the project is notifiable. A non-notifiable project with multiple contractors has exactly the same CDM duties — PD appointment, PC appointment, CPP, H&S File — as a notifiable project with multiple contractors. The only difference is whether an F10 is submitted.
| Scenario | CDM Duties |
|---|---|
| Notifiable + multiple contractors | PD appointment, PC appointment, written CPP, H&S File, PCIP, F10 notification. All CDM duties apply in full. |
| Notifiable + single contractor | Contractor takes on PD and PC roles by default. Written CPP required. H&S File required. F10 notification required. No separate PD/PC appointments needed. |
| Non-notifiable + multiple contractors | PD appointment, PC appointment, written CPP, H&S File, PCIP. All duties identical to a notifiable project — except no F10 notification. |
| Non-notifiable + single contractor | Contractor takes on PD and PC roles by default. Written CPP still required. H&S File still required. No F10. Lightest compliance burden, but duties still exist. |
The practical implication
Do not assume that because a project is not notifiable, CDM duties are reduced or do not apply. The number of contractors determines the duties. A £50,000 shop fit-out with three subcontractors is non-notifiable but requires PD and PC appointments, a written CPP, and a H&S File — exactly the same duties as a £10 million new-build. The only thing the non-notifiable project does not need is the F10.
8. Six Common Misconceptions
The F10 generates more misunderstandings than almost any other CDM document.
Only notifiable projects need CDM compliance
WRONG. CDM 2015 applies to ALL construction projects in Great Britain. Notification thresholds determine whether an F10 is submitted — they do not determine whether CDM duties apply. A non-notifiable project with multiple contractors requires PD and PC appointments, a written CPP, and a H&S File, exactly like a notifiable project.
Once you notify, your CDM duties are done
WRONG. The F10 is a notification — not a compliance certificate. Submitting it simply tells the HSE the project exists. All other CDM duties — PCIP, CPP, PD/PC appointments, H&S File, welfare facilities, site inductions, competence checks — must still be discharged independently. The F10 does not tick any other compliance box.
The F10 triggers Principal Designer and Principal Contractor appointments
OUTDATED. Under CDM 2007, this was true — notifiability triggered the requirement for a CDM Coordinator. Under CDM 2015, PD and PC appointments are triggered by having more than one contractor, not by notification. A non-notifiable project with multiple contractors still requires both appointments.
You only notify if more than 30 working days AND more than 20 workers
INCOMPLETE. This describes only Threshold A. Threshold B — more than 500 person-days — is entirely independent. A project with 8 workers for 70 days (560 person-days) is notifiable under Threshold B alone, even though it never has more than 20 workers on site.
You submit one F10 and never need to update it
WRONG. The F10 must be updated whenever key details change — particularly the PC or PD appointment, the planned start date, or significant changes to the project scope, duration, or workforce. The updated notification is resubmitted via the same online portal. An outdated F10 displayed on site is a compliance failure.
The F10 can be submitted by post or email
WRONG. The HSE only accepts F10 notifications via the online portal. There is no paper form, no email address for submissions, and no postal address. This has been the case since the online portal was introduced. Any notification submitted by other means will not be recorded.
10. A Real-World Example
A property developer is building 12 houses on a greenfield site. The project is expected to last 14 months with a peak workforce of 35 workers across six subcontractors. The total estimated person-days exceed 3,000. The project comfortably exceeds both Threshold A (more than 30 working days and more than 20 simultaneous workers) and Threshold B (more than 500 person-days). It is notifiable.
The developer appoints a Principal Designer and Principal Contractor before the construction phase begins. The PD assists in compiling the Pre-Construction Information Pack. The developer — as client — submits the F10 via the HSE online portal three weeks before the planned start date, including the PD and PC details, the site address, the estimated workforce, and the planned duration. A copy of the F10 confirmation is printed and displayed in the site office. Two months into the project, the PC is replaced after going into administration. The developer resubmits the F10 with the new PC's details and updates the site office copy.
The F10 was one small step — submitted in under 15 minutes. The CDM compliance framework that sat behind it — PCIP, CPP, PD and PC appointments, welfare facilities, H&S File — took considerably longer. The notification tells the HSE the project exists. Everything else is what actually keeps people safe.
11. Frequently Asked Questions
Is an F10 required on every construction project?▾
No. An F10 is only required on notifiable projects — those exceeding the thresholds in CDM 2015 Regulation 6(1). Most construction projects, particularly smaller commercial works and most domestic projects, will not meet either threshold and do not require an F10. However, all CDM duties still apply regardless of notification status.
Does the F10 trigger the requirement to appoint a PD and PC?▾
No. Under CDM 2015, PD and PC appointments are triggered by having more than one contractor on the project — not by notification. This is a change from CDM 2007, where notifiability did trigger additional appointment duties. A non-notifiable project with multiple contractors still requires PD and PC appointments.
Who submits the F10?▾
The client holds the legal duty to notify under CDM 2015 Regulation 6. The client can delegate the practical task of completing the online form to the PD, PC, or any agent — but the legal responsibility for ensuring it is submitted, and that the information is accurate, remains with the client.
When exactly must the F10 be submitted?▾
As soon as practicable before the construction phase begins. CDM 2015 does not prescribe a specific number of days in advance. The previous requirement under CDM 2007 for a fixed notice period was removed. The test is whether the client submitted it as soon as they reasonably could — not whether a specific number of days' notice was given.
Can the F10 be submitted by post or email?▾
No. The HSE only accepts F10 notifications via the online portal at hse.gov.uk/forms/notification/f10.htm. There is no paper form, no email address for submissions, and no postal option. Any notification submitted by other means will not be recorded by the HSE.
What if my project becomes notifiable after it has started?▾
Submit the F10 immediately. Projects can become notifiable mid-works if scope changes, programme extensions, or additional workforce mean the thresholds are now met. The duty to notify arises as soon as it becomes apparent the thresholds will be met. Late notification is a breach, but it is far better than no notification.
Does the F10 need to be displayed on site?▾
Yes. An up-to-date copy of the F10 notification must be displayed in the site office or another prominent location where it can be read by anyone working on the project. If the F10 is updated — for example because the PC changes — the displayed copy must be updated too.
Do railway projects notify the HSE?▾
No. Construction work on or adjacent to the railway is regulated by the Office of Rail and Road (ORR), not the HSE. Railway projects notify the ORR. Similarly, construction on licensed nuclear sites is regulated by the Office for Nuclear Regulation (ONR). Standard construction projects notify the HSE.
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