Where this document applies
1. This approved document gives guidance on what, in ordinary circumstances, may be considered reasonable provision to comply with the requirements of regulations 26 and 40 of, and Part L of Schedule 1 to, the Building Regulations in relation to works comprising: a. The construction of new buildings other than dwellings. b. Fit-out work where the work is either part of the construction of a new building, or is the first fit-out of a shell and core development where the shell is sold or let before the fit-out work is carried out. (Approved Document L2B applies to fit-out work in other circumstances.) c. The construction of extensions to existing buildings that are not dwellings where the total useful floor area of the extension is greater than 100 m² and greater than 25 per cent of the total useful floor area of the existing building. In addition, this approved document gives guidance on how to comply with regulations 25A, 27, 43 and 44 of the Building Regulations, and regulation 20 of the Building (Approved Inspectors etc.) Regulations 2010 where an approved inspector is the BCB. 2. When a building that contains dwellings is being constructed, account should also be taken of the guidance in Approved Document L1A. In most instances, use Approved Document L1A for guidance relating to the work on the individual dwellings, and this Approved Document L2A for guidance relating to the parts of the building that are not a dwelling, such as heated common areas and, in the case of mixed-use developments, the commercial or retail space. NOTE: Dwelling includes a dwelling-house and a flat and means self-contained units designed to accommodate a single household. For new boarding houses, hostels and student accommodation blocks that contain rooms for residential purposes this approved document applies. 3. If a building contains both living accommodation and space to be used for commercial purposes (e.g. as a workshop or office), the whole building should be treated as a dwelling as long as the commercial part can revert to domestic use. This can be the case if, for example: a. there is direct access between the industrial or commercial space and the living accommodation; and b. both are contained within the same thermal envelope; and c. the living accommodation occupies a substantial proportion of the total area of the building. NOTE: Sub-paragraph c means that, for example, the presence of a small flat for a manager in a large non-domestic building does not result in the whole building being treated as a dwelling. Similarly, if a room is used as an office or utility space within a dwelling that does not mean that the building should not be treated as a dwelling.