PPS 7 Addendum Residential Extensions and Alterations·Page 14·A17
Dormer windows visibility and design
Dormer windows open to public view can interfere with the original design and street scene; dormers to the front or side will be resisted where uncharacteristic, especially large box dormers. Dormers should be kept to a minimum, located below the ridge line, and positioned vertically in line with windows below in smaller size to avoid a top-heavy appearance.
Where a dormer is open to public view, it can interfere with both the original design of the existing building and cause a visual intrusion into the street scene or rural setting. Dormer windows to the front or side of a property will be resisted in areas where they are uncharacteristic, particularly large box dormers that are over-dominant often extending the full width of the roof. The size and number of dormers should therefore be kept to a minimum to avoid dominating the appearance of the roof and should be located below the ridge line of the existing roof. Positioning dormer windows vertically in line with the windows below and ensuring that they are smaller in size will usually avoid a top-heavy or unbalanced appearance.
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