6.1 Regulation 28 of the Building Regulations may require additional work to be undertaken to make an existing building more energy efficient when certain types of building work are proposed.
6.2 This requirement arises in existing buildings with a total useful floor area of over 1,000 m² where the proposed work consists of:
a. an extension;
b. the initial provision of any fixed building service (other than a renewable energy generator);
c. an increase to the installed capacity of any fixed building service (other than a renewable energy generator);
6.3 Consequential improvements should only be carried out to the extent that they are technically, functionally and economically feasible.
6.4 Only a relatively small number of existing dwellings will exceed 1,000 m² in size. Where there is doubt the BCB can be consulted for advice.
6.5 Technical guidance on achieving compliance with regulation 28 is not given in this Approved Document but where the regulation applies it is available in Approved Document L2B.