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

R23(2), LO1N(aL I)N E V E R S I O N Section 10: New elements in existing buildings, including extensions General 10.1 This section provides guidance for new elements in existing buildings, including all the following types of work. a. Providing a new thermal element in an existing building – follow paragraph 10.2. b. Providing a replacement thermal element in an existing building – follow paragraph 10.2. c. Replacing windows, doors or rooflights (controlled fittings) in an existing building – follow paragraphs 10.3 to 10.5. d. Extending an existing building – follow paragraphs 10.6 to 10.11. e. Adding a conservatory or porch to an existing building – follow paragraphs 10.12 and 10.13. NOTE: Guidance for renovating or retaining elements in existing buildings is given in Section 11. New and replacement thermal elements 10.2 The minimum standards in paragraphs 4.5 and 4.6 and Table 4.1 should be met for both of the following. a. New thermal elements installed in an existing building. b. Thermal elements constructed to replace existing thermal elements. New and replacement windows, roof windows, rooflights and doors (controlled fittings) 10.3 If the entire unit of windows, roof windows, rooflights or doors is replaced, all the following apply. a. Units should be draught-proofed. b. Units should meet the minimum standards in Table 4.1. c. Insulated cavity closers should be installed where appropriate. 10.4 For windows used in buildings similar to dwellings, building control bodies may accept, as evidence of compliance with the standards given in Table 4.1, a Window Energy Rating from a certification scheme that provides a quality assured process and supporting audit trail from calculating the performance of the window through to the window being installed. 70 Approved Document L Volume 2, 2021 edition Building Regulations 2010 O N L I N E V E R S I O N