Belfast·SPG004 Residential Extensions and Alterations·Page 27·4.1.25
Permitted development requirements for dormer windows
Dormer windows permitted under development rights must use exterior materials similar to the existing house, be appropriately sited and dimensioned, and no part of the dormer should exceed the height of the existing roof.
What is allowed without planning permission applies largely to location, siting and the dimensions of the proposed roof extension. The materials used in any exterior work should be of similar appearance to those used on the existing house. No part of the dormer should be higher than the highest part of the existing roof.
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