http://www.legislation.gov.uk/asc/2026/5/section/6Building Safety (Wales) Act 2026enStatute Law Database2026-06-22Expert Participation2026-04-28 PART 1CHAPTER 2 6 1 Regulated buildings are divided into 3 categories for the purposes of this Act. 2 A regulated building is a category 1 building if it— a is at least 18 metres in height, or b has at least 7 storeys. 3 A regulated building is a category 2 building if it— a is less than 18 metres in height and has fewer than 7 storeys, and b is at least 11 metres in height or has at least 5 storeys. 4 A regulated building is a category 3 building if it— a is less than 11 metres in height, and b has fewer than 5 storeys. 5 For the purposes of this section— a a mezzanine floor is to be regarded as a storey if its internal floor area is at least half of the internal floor area of the largest storey in the building that is not below ground level; b a storey is below ground level if the whole of the finished surface of the ceiling of the storey is below ground level; c “ground level” means— i where the level of the surface of the ground on which the building is situated is uniform, the level of the surface of the ground immediately adjacent to the building; ii where the level of the surface of the ground on which the building is situated is not uniform, the level of the lowest part of the surface of the ground immediately adjacent to the building. 6 The Welsh Ministers may by regulations make further provision for the purposes of this section. 7 The regulations may in particular— a make provision about how the height or number of storeys of a regulated building is to be determined, which may include requiring that account be taken of parts of a structure or set of structures of which the building forms part; b provide that a regulated building of a description specified in the regulations that would otherwise fall into a category set out in this section falls into a different category. S. 6 in force at 28.4.2026, see s. 138(1)(a)