Glossary
Principal designer
A principal designer is the dutyholder who plans, manages and monitors the design work’s health-and-safety and, under Building Regulations dutyholder rules in England, helps ensure design compliance. Domestic clients often appoint one when several designers are involved.
On smaller projects the lead designer may take the role if competent and appointed in writing.
CDM and Building Regulations dutyholder labels differ by nation; always check the regime that applies where the site is.
Official source: Dutyholders under the Building Regulations (HSE). Checked 27 October 2026.