PPS 7 (Addendum): Residential Extensions and Alterations
Annex A: Residential Amenity
A27 The Department considers it important that the amenity of all residents is protected from ‘unneighbourly’ extensions as these can cause problems through overshadowing/loss of light, dominance and loss of privacy. The extent to which potential problems may arise is usually dependent upon the separation distance, height, depth, mass and location of an extension and window positions. Single-storey extensions to the rear of a semi-detached or terraced dwelling will generally be acceptable where the depth does not exceed 3.5 metres from the back wall of the original building, at the boundary with an adjoining dwelling. Larger extensions will be assessed in light of the following guidance, although it is acknowledged that flexibility may be needed in respect of older properties with small plot areas or where the proposal seeks to meet the specific needs of a person with a disability.