PPS 7 Addendum Residential Extensions and Alterations·Page 11·2.10
Outbuilding conversion and extension requirements
Where extending the main house is impractical, converting and extending an existing outbuilding is acceptable only if it provides modest accommodation to remain ancillary to the main dwelling. Self-contained separate buildings within the curtilage will not be permitted unless they would qualify as independent dwellings.
Where an extension to the existing house is not practicable and it is proposed to convert and extend an existing outbuilding, planning permission will normally depend on the development providing a modest scale of accommodation. The purpose of this is to ensure the use of the building as part of the main dwelling. The construction of a separate building, as self contained accommodation, within the curtilage of an existing dwelling house will not be acceptable, unless a separate dwelling would be granted permission in its own right. Other proposals for ancillary residential use which are clearly incidental to the enjoyment of the property, such as a garden room or a gazebo, will be treated on their merits within the terms of the policy.
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