This Health Building Note (HBN) provides evidence-based best practice guidance on the design and layout of generic clinical and clinical support spaces for use in healthcare settings. Room sizes have been standardised wherever possible. For clinical support areas where a standard room size is not appropriate, this document provides a sizing methodology suitable for briefing purposes. Most of the indicative room layouts are informed by one or more ergonomic drawings. In places, the guidance differs from that provided in Approved Document M (2010) and BS 8300:2001 (2009 edition). Where this is the case, the reasons for the variations are discussed