B5.1.4 Materials and detailing

All extensions and dormers should use materials that match or complement the existing building and respect the prevailing character of the wider streetscene, to ensure a cohesive and sympathetic appearance. Proposals for contrasting materials, such as render or cladding, should ensure that they will not harm the visual character of the original building or surrounding area.

Exception: This design guidance is strongly encouraged but does not apply to dormers constructed under Permitted Development rights where planning permission is not required.

Materials that are prone to staining, weathering unevenly, or rapid visual deterioration must be avoided, as they can detract from the long-term quality and appearance of the development. Applicants must demonstrate the durability and weathering performance of proposed materials through manufacturer specifications, precedent examples, or material samples, particularly for exposed or prominent elevations.

The design of windows and doors should be in keeping with the architectural rhythm of the existing building, ensuring consistency in proportion, alignment, and style. Any alterations to front-facing elevations should respect the established building line and contribute positively to the character and appearance of the surrounding streetscape.