Conservation of fuel and power: Approved Document L, Volume 1 — Dwellings

O N L I N E V E R S I O N L1(a) In the Secretary of State’s view, requirement L1(a) is met for work on an existing dwelling by achieving both of the following, where relevant to the work being done. a. Unwanted heat losses from the dwelling 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 4.5 and paragraphs 4.7 to 4.14, 4.16 and 4.19. 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 4.23. b. Unwanted heat gains from any pipework and services to which building work is being done are limited by following the guidance in paragraphs 4.24 to 4.32. NOTE: If work includes an extension to an existing dwelling, initial provision of fixed building services or an increase to the installed capacity of fixed building services, consequential improvements may be required – Section 12. 22 Approved Document L Volume 1, 2021 edition Building Regulations 2010 O N L I N E V E R S I O N