Sometimes, understanding regulations is tricky. Here at Osprey Solent we try to make it as easy as possible.

If you are undertaking construction work or are a client for some construction work you will want peace of mind on whether you need to notify the Health and Safety Executive (HSE) about your project.

We have created an easy to use calculator to help guide you if you are unsure if your construction project should be notified.

All construction projects must comply with the notification requirements under the Construction (Design and Management) Regulations 2015 (CDM 2015) regardless of whether the project is classified as domestic or commercial, you must notify the HSE if it surpasses the notification level.

NOTE: Even if the project is not notifiable, it is important to remember that all CDM obligations still apply, including the requirement to appoint the Principal Designer and Principal Contractor duties.

Work out whether your project needs to be notified to the HSE under the Construction (Design and Management) Regulations 2015



If your construction project will ever have more than 20 workers, at any one time, and the project exceeds 30 working days (including part days) – it is notifiable to the HSE.

It is also important to check on the number of person days your project is forecasted to have, because a project can still become notifiable even if the duration is under 30 days with less than 20 people.

For example, a project lasting 29 days with 19 workers would still require notification because it exceeds the 500 person day rule.

The notification thresholds required under CDM 2015 are where the project will:

  1. Last longer than 30 working days and have more than 20 workers working simultaneously at any point in the project; or
  2. Exceed 500 person days