Compliance · September 2026 · 5 min read

What is an F10 notification?

If a construction project reaches a certain size, the law says you have to tell the Health and Safety Executive about it before work starts. That notification is the F10. Here is what it is, when you need one, and whose job it is.

The short version

An F10 is the form you use to notify the HSE of a notifiable construction project under the Construction (Design and Management) Regulations 2015, better known as CDM 2015. It is submitted online through the HSE website, and a copy has to be displayed where workers can see it on site.

When is a project notifiable?

A construction project must be notified to the HSE if it is expected to either:

• last longer than 30 working days and have more than 20 workers working at the same time at any point in the project; or
• exceed 500 person-days of construction work.

A person-day is simply one person working for one day. So a job with 10 workers running for 55 days is 550 person-days, and would be notifiable even if you never have 20 people on at once.

Whose job is it?

The duty to notify sits with the client - the person or organisation the work is being carried out for. In practice the principal contractor often prepares and submits it, but the legal duty stays with the client. If you are the client and you assume someone else has done it, check: an unsubmitted F10 is your problem, not theirs.

What has to happen, and when

• Notify the HSE before the construction phase begins.
• Display a copy of the notification on site, somewhere workers can read it, and keep it up to date.
• Update the HSE if the key details change significantly.

What happens if you do not

Failing to notify a notifiable project is a breach of CDM 2015. On its own it is unlikely to be the end of the world, but it is exactly the kind of basic administrative miss that colours how an inspector views the rest of your site. If something goes wrong and the paperwork was not in order, it makes a bad day worse.

How to stay on top of it

The honest problem with F10 is not the form - it takes minutes - it is remembering to do it, and spotting the moment a growing project tips over the threshold. The reliable way to handle it is to track two numbers as the job runs: how long it is taking, and how many people are on it. Once those cross the line, the notification needs to go in.

This is one of the things Avelio Pro does automatically - it tracks project duration and worker numbers, and flags when a project becomes notifiable so the F10 is not left to memory.