Conservation of fuel and power: Approved Document L, Volume 2 — Buildings other than dwellings

O N L I N E V E R S I O N b. The commercial space and the living accommodation are within the same thermal envelope. c. The living accommodation comprises a substantial proportion of the total area of the unit. What constitutes a ‘substantial proportion’ should be assessed on a case-by-case basis by the building control body. NOTE: A large non-domestic building that contains a small flat for a manager is not treated as a dwelling. A dwelling that contains a room used as an office or utility space is still treated as a dwelling. Mixed-use developments 0.22 When constructing a building that contains dwellings and other types of accommodation, sometimes called a mixed-use development, refer to the two volumes of Approved Document L as follows. a. For guidance on each individual dwelling, use Approved Document L, Volume 1: Dwellings. b. For guidance on the non-dwelling parts of the building, such as heated common areas and any commercial or retail space, use this approved document. Selected key interactions with other parts of the Building Regulations 0.23 The approved documents set out what, in ordinary circumstances, may be accepted as one way to comply with the Building Regulations. Those designing or undertaking building work remain responsible for assessing, on a case-by-case basis, whether specific circumstances require additional or alternative measures to achieve compliance with the regulatory requirements. There are interactions between many of the requirements of the Building Regulations. Guidance on some key interactions is given below. Interaction with Part C 0.24 This approved document, Approved Document L, Volume 2, provides guidance and examples on upgrading thermal elements. For interstitial and surface condensation, a lesser standard may be acceptable. Guidance in Approved Document C should be followed. Interaction with Part E 0.25 This approved document, Approved Document L, Volume 2, provides guidance on insulation that is reasonably continuous and limits thermal bridging. Construction junctions should limit noise transfer where Part E of the Building Regulations sets a requirement. Approved Document E should be followed. Interaction with Part F 0.26 This approved document, Approved Document L, Volume 2, provides guidance on reducing unwanted heat loss, by achieving optimum airtightness. When specifying the minimum amount of purpose- provided ventilation, consider the air infiltration of a building; follow Approved Document F. Interaction with Part J 0.27 This approved document, Approved Document L, Volume 2, provides guidance on airtightness. For guidance on permanent ventilation openings for open flued appliances in very airtight buildings, follow Approved Document J. Interaction with Part K and Part M 0.28 This approved document, Approved Document L, Volume 2, provides guidance on controls for fixed building services and on-site electricity generation. Manual controls, where provided, should be within reasonable reach of the occupants. Follow the guidance in Approved Documents K and M. 5 Building Regulations 2010 Approved Document L Volume 2, 2021 edition O N L I N E V E R S I O N