The Construction (Design and Management) Regulations 2015 set out duties for all parties in a construction project: clients, designers, principal designers, principal contractors, and contractors. They apply to ALL construction work in Great Britain, regardless of size.

What are the F10 notification thresholds?

A project is notifiable if it will last more than 30 working days AND have more than 20 workers on site simultaneously at any point, OR will involve more than 500 person-days of construction work in total. Both thresholds must be checked.

How do I submit an F10?

The F10 notification is submitted online via the HSE website before construction work begins. It must include: project description, client and contractor details, dates, and names of principal designer and principal contractor. It is the client's duty to ensure notification.

Who is the principal contractor under CDM?

The principal contractor (PC) is appointed by the client for projects with more than one contractor. The PC plans, manages, and coordinates the construction phase, produces the construction phase plan, and ensures all contractors cooperate on health and safety.

Does CDM apply to domestic projects?

Yes, CDM 2015 applies to all construction work including domestic projects. However, for domestic clients (homeowners), the contractor or principal contractor automatically takes on the client duties unless the homeowner makes written appointment of a client advisor.

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CDM Notification Calculator

Determine if your project requires F10 notification to HSE

Project Duration

Max Workers at Any Time

Total Person-Days

How We Calculate This

Enter the project duration in working days, maximum number of workers on site at any time, and total person-days of construction work. The calculator checks against both CDM 2015 notification thresholds. It also identifies whether appointments of principal designer and principal contractor are required, and lists the key CDM duties that apply to your project.

Frequently Asked Questions

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Last updated: March 2026

All calculations are estimates. Verify with your supplier.