Roof Extensions and dormers, chimney stacks and pots
The existing roofs are very important to the character of the area. These include a variety of types such as exposed pitched roofs, mansards, gables and front parapets with hidden roofs.

Many  retain their original natural slate coverings and decorative features. The Council considers that the ad-hoc construction of roof extensions, dormers and rooflights can be very damaging to the appearance of the area and consent will not normally be given for alterations to roofs which are visible from the street, side streets or other public areas.

New or enlarged dormers or rooflights on front or side slopes of exposed pitched roofs will not be permitted. Plant or tank rooms, air conditioning units or other services will not be allowed at roof level where it is visible from the street, including long views. The Council wishes to see existing chimney stacks and pots retained.

Side Extensions
The existing gaps between detached, semi-detached and groups of villas afford pleasant views to trees and rear gardens and give Canonbury a spacious and distinctive character. The construction of large and high side extensions erodes this character and blocks the views of green and open spaces.

Permission will only be given for new or replacement side extensions where they do not exceed three metres in height above ground level and are set back by at least three metres from the front corner of the house. Two storey extensions may be acceptable but only where they do not exceed two metres in width and leave a gap of at least three metres between the extension and the property boundary.  All extensions should have a flat or low pitch roof hidden behind a horizontal front and side parapet.