Technical Booklet F1 Conservation of Fuel and Power in Dwellings·Page 10·41
Consequential improvements
When building work is carried out on existing buildings over 1000 m² (including extensions or changes to fixed building services), consequential improvements must be made to ensure the building complies with conservation requirements where technically, functionally and economically feasible.
Where it is proposed to execute building work in relation to any existing building with a total useful floor area greater than 1000 m2 and that work consists of or includes—
(a) an extension;
(b) the initial provision of any fixed building service; or
(c) an increase in the capacity of any fixed building service,
consequential improvements to the existing building shall be carried out to ensure that the building complies with the requirements of regulation 39 so far as this is technically, functionally and economically feasible.
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