PPS 7 (Addendum): Residential Extensions and Alterations
Annex A: Extensions and Alterations to provide for Ancillary Uses
A49 An extension or alteration to a residential property to provide an ancillary use, such as additional living accommodation for elderly or dependent relatives, should be designed to demonstrate dependency on the existing residential property. Proposals of this nature should be designed in such a manner as to easily enable the extension to be later used as an integral part of the main residential property. Ancillary uses should provide limited accommodation and shared facilities, for example kitchens and be physically linked internally to the host property. Ancillary uses that could practically and viably operate on their own will not be acceptable.