The documents
When is a construction project notifiable to HSE?
Short answer
A project is notifiable if the construction work is scheduled either to last longer than 30 working days and have more than 20 workers working simultaneously at any point, or to exceed 500 person days. Those are the only two tests. Value, complexity, whether the work is domestic and whether a principal designer is required have nothing to do with it.
Test one: duration and simultaneous workers
Longer than 30 working days and more than 20 workers at the same time. Both halves.
| Project | Days | Peak workers | Test one |
|---|---|---|---|
| Domestic rear extension | 60 | 5 | Not met, worker count |
| Office fit out, fast track | 25 | 30 | Not met, duration |
| Small housing scheme | 180 | 25 | Met |
Test two: person days
More than 500 person days across the whole project. Multiply the number of people by the days they work, and add it up.
| Project | Arithmetic | Person days | Test two |
|---|---|---|---|
| Domestic rear extension | 4 people, 60 days | 240 | Not met |
| Whole house refurbishment | 6 people, 100 days | 600 | Met |
| Office fit out | 30 people, 25 days | 750 | Met |
Note the last two rows. A project can fail test one and still be notifiable on test two, which is why both have to be checked.
Do this with your own figures.
Scheduled, not actual
The regulation talks about work that is scheduled to last or to exceed those figures, so the judgement is made from the programme before work starts, not from what happens afterwards. If the programme changes materially and the project crosses a threshold, the notification should be made then.
Why most domestic work is not notifiable
Because the numbers are simply not close. A large domestic extension might run five months with an average of three or four people and a peak of eight on a busy week. That is around 300 person days and never more than 20 people at once. It needs a principal designer, a construction phase plan and a health and safety file, and it does not need an F10.
Anyone telling a homeowner their extension must be notified to HSE is worth asking to show the arithmetic.
Sources
- CDM 2015, regulation 6: notification legislation.gov.uk
- CDM 2015, regulation 7: application to domestic clients legislation.gov.uk
- HSE: how to notify a project (F10) hse.gov.uk
Check the threshold
The free checker does both tests, shows the arithmetic, and tells you plainly whether the project is likely to be notifiable.
Open the F10 checker →Not sure yet? get a fixed fee for the appointment.