Height + storey calculation
18m measured from lowest external ground level adjacent to building to top of finished floor of top storey. Storeys = count habitable storeys above ground (basements excluded from storey count but included in height if any part above ground). 7+ storey threshold catches buildings in dense urban form which may be shorter than 18m but still high-risk (Barbican 7-storey blocks just under 18m still HRBs). Roof plant + lift overrun excluded from height calc. Mezzanine excluded from storey count if <50% floor area.
London HRB inventory + Accountable Person
~5,000 London HRBs registered with Building Safety Regulator (BSR). Concentrations: Tower Hamlets (Canary Wharf, Isle of Dogs), Newham (Stratford), City of London (Barbican, Cromwell Tower), Southwark (Elephant Park), LBHF (high-rise estates), Westminster (post-war towers). Each HRB has Accountable Person (typically freeholder or RTM company) responsible for safety case report — assessment of building safety risks + mitigations + ongoing monitoring. Safety case must be reviewed annually + updated after any building work. Penalties for non-compliance: criminal — fines + imprisonment for directors.
What this means for flat renovations in HRBs
If you own a flat in an HRB and want to renovate: (1) freeholder/Accountable Person consent needed (Licence to Alter); (2) Gateway 2 approval from BSR before work starts if work affects relevant external/fire safety elements (façade, fire compartmentation, escape routes) OR is 'major refurbishment'; (3) work by competent contractors with golden thread updated. Cosmetic-only refurbishment (paint, floor finish, kitchen replacement without altering compartmentation) usually outside Gateway 2 — but still requires golden thread update. Builderr does not currently take HRB-scope work; we advise potential HRB clients to use specialist contractors (BSR-registered) and refer where appropriate.
