F10 Notification: When a Project Is Notifiable, Who Notifies, and the Mistakes to Avoid

The Two Thresholds

Under CDM 2015, a project is notifiable to the HSE if the construction work is expected to last longer than 30 working days and have more than 20 workers working simultaneously at any point, or exceed 500 person-days of construction work. Both routes matter and they trip people up in different directions. The first is a compound test — a 6-month job that never has more than a dozen people on site at once does not qualify under it. The second is a pure volume test with no duration or headcount condition: 25 people for a month sails past 500 person-days regardless of the fact it never felt like a "big" project.

Person-days count anyone carrying out construction work, and the estimate is made in advance — the duty is triggered by what the project is expected to involve. Working days are days on which construction work takes place; a Saturday shift is a working day. When the arithmetic is close, do the sum honestly and keep it: a project team that can show a reasoned 460 person-day estimate is in a very different position from one that never did the calculation.

Whose Duty It Is

Notification is the client's duty. The client must give notice in writing to the HSE as soon as is practicable before the construction phase begins — in practice via the online F10 form. Commercial clients routinely ask the principal contractor or principal designer to submit on their behalf, which is fine as an arrangement, but the legal duty does not move: if nobody notifies, it is the client the regulation points at. On domestic projects the client's duties transfer under CDM, so the contractor (or principal contractor) effectively picks this up.

The particulars are set out in Schedule 1: the project's address and description, planned start date and duration, the client, principal designer and principal contractor with contact details, the maximum number of people at work at any one time, and the number of contractors expected. Nothing exotic — the difficulty is never the form, it is remembering the duty exists and keeping the submission current.

Display It, Update It

Two follow-through duties get missed more often than the notification itself. The notice must be displayed on site where workers can read it — the F10 print-out in the induction room or on the site notice board, updated when it changes, is the standard answer, and it is one of the first things an HSE inspector looks for on arrival. And the notification must be kept up to date: a new principal contractor, a materially extended duration, a change of client — these are updates, not trivia. An F10 naming a principal contractor who left the job a year ago tells an inspector something about how the project manages everything else.

The Project That Grows

The classic failure is the job that was genuinely below threshold at the start and grew — the two variations that added a month, the second gang that doubled the headcount. The moment the honest expectation crosses a threshold, notify then. Late notification because the project changed is an administrative catch-up; carrying on for months past the line with no F10 because "it wasn't notifiable when we priced it" is a breach that is visible from space. Build the check into change control: any variation that adds duration or resource gets the thresholds re-run as part of its assessment. It takes thirty seconds.

What Notification Does and Does Not Change

It is worth being clear about what the F10 is not. Notifiability no longer determines whether CDM duties apply — since 2015 the appointment of a principal designer and principal contractor hangs on whether more than one contractor is involved, and a construction phase plan is required on every project. The F10 does not approve anything, license anything or certify anything; it tells the regulator the project exists so inspection can be targeted. Which is also the practical reality to plan for: a notified project is a visible project. The F10 landing at the HSE is a perfectly good prompt to make sure the construction phase plan, the welfare and the management arrangements it advertises are actually in place before the first boots arrive — because the follow-up knock on the cabin door has a habit of coming early.