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

L1(a) O N L I N E V E R S I O N In the Secretary of State’s view, requirement L1(a) is met for the work being done to an existing building by achieving both of the following, where relevant to the work being done. a. Unwanted heat losses from the building are limited by meeting the standards for all of the following. i. Any building fabric to which building work is being done, including walls, floors, roof, windows and openings – paragraphs 4.1 to 4.14. Further guidance is given in the following sections. • For new elements, replacement elements and extensions – Section 10. • For renovated elements, retained elements, a change to energy status and a material change of use – Section 11. ii. Any work that may result in making airtightness worse – paragraph 4.15. iii. Any pipework and services to which building work is being done – paragraphs 4.19 to 4.25. b. Unwanted heat gains to the building, throughout the year, through any of the routes listed in point (a) are limited as set out in Section 4. NOTE: If work includes an extension to an existing building, initial provision of fixed building services, or an increase in the installed capacity of fixed building services, consequential improvements may be required – Section 12. 22 Approved Document L Volume 2, 2021 edition Building Regulations 2010 O N L I N E V E R S I O N