What is a Principal Designer in Construction?

Lee Marsden
September 26, 2025
Lee Marsden
September 26, 2025

The Principal Designer plays a critical role in health and safety planning during the pre-construction phase of a project. Appointing a competent Principal Designer is a legal requirement under CDM 2015 regulations for projects involving more than one contractor.

At Majestic Site Management, we deliver expert Principal Designer services to ensure compliance, risk reduction and smooth coordination across public and commercial builds.

  • A Principal Designer is a legally required role under CDM 2015 on projects with more than one contractor, responsible for planning, managing, and coordinating health and safety during the pre-construction (design) phase.
  • Their key duties include identifying and reducing design risks, coordinating designers, and sharing safety information with the Principal Contractor, helping ensure projects are safe, compliant, and well-managed from the outset.

What Does a Principal Designer Do?

The Principal Designer is responsible for managing health and safety in the design stage of construction. Their core duties include:

  • Planning, managing and monitoring the pre-construction phase
  • Identifying and eliminating potential design risks
  • Ensuring designers comply with CDM 2015 duties
  • Working with the Principal Contractor to share risk information
  • Producing and coordinating pre-construction information

When is a Principal Designer Required?

CDM 2015 states that a Principal Designer must be appointed on any project with more than one contractor. This includes domestic, commercial and public sector works involving multiple trades.

Without a Principal Designer, the client becomes legally responsible for health and safety coordination — a risk many public sector bodies and developers can’t afford to take.

Principal Designer vs Principal Contractor

The Principal Designer works during the pre-construction phase to manage design risks, while the Principal Contractor manages safety and site logistics during the construction phase.

Both roles must collaborate closely and share health and safety information throughout the build.

What Makes a Good Principal Designer?

Principal Designers must have proven experience in construction design, plus relevant health and safety knowledge. Look for professionals with:

  • Understanding of risk mitigation through design
  • Familiarity with HSE guidance and CDM 2015 duties
  • Strong communication skills to coordinate with designers, contractors and clients

We offer Principal Designer services across all project sizes and sectors.

Need a Qualified Principal Designer?

Appointing a competent Principal Designer ensures you meet legal duties under CDM 2015 and avoid future safety risks, delays and compliance penalties.

Majestic Site Management provides expert support across the full project lifecycle, from design through to delivery. We’re trusted on council frameworks and major private developments alike.

Get in touch to appoint a Principal Designer for your next project.