Interestingly, the government did not agree with the decision of the First Tier Tribunal on whether to measure a rooftop garden as a storey in a Higher Risk Building. The Higher-Risk Buildings (Descriptions and Supplementary Provisions) Regulations 2023 explains that when you measure the height of a building from ground level to the top of the floor surface of the top story you can ignore any storey consisting entirely of plant or machinery and you can ignore a storey below ground level. You can also ignore a storey which has a gallery with an internal floor area that is less than 50% of the internal floor area of the largest storey vertically above or below it which is not below ground level.
Government Guidance was issued in 2023 in order to clarify that a storey must be fully enclosed to be considered a storey and that the roof of a building should not be counted as a storey including open rooftops such as rooftop gardens. However, the First Tier Tribunal published a decision in Smoke House & Curing House, 18 Remus Road where it noted that the Government Guidance appears to contradict the Building Safety Act and Regulations and the tribunal rejected the guidance as not constituting a reliable method of interpretation of law. This prompted a statement issued by MHCLG noting that the Tribunal had acknowledged that it did not have jurisdiction to make this finding and until stated otherwise, the sector and regulatory bodies should continue to refer to the existing government guidance. Watch this space – it is likely the method of naming a building a higher-risk building solely due to its height will change since it is recognised as a blunt instrument for measuring risk.