Appeal 3370357

The appeal is dismissed.

The main issues are the effect of the development on i) the character and appearance of the host property and the surrounding area, and ii) the living environment for the occupiers.

This proposal follows an earlier scheme for a larger rear dormer which was dismissed on appeal in February 2025 – [name]/D3640/D/25/3358888. That scheme was found to be harmful to both the character and appearance of the host property and the living conditions of the occupiers of the adjoining properties to the rear.

No.9 is a modern detached house which has been extended to the side. The first floor extends into the roof and is served by dormer windows with hipped roofs. To the rear is a central two-storey projection with the dormer windows to either side. The proposed box-style dormer addition would sit above and wrap around the existing projection. With dropped eaves, the appeal property, along with its neighbours, which are of a similar design, have relatively expansive and prominent roof slopes. The flat-roofed, elongated form would create an incongruous feature that disturbs the roofscape and contrasts with the existing form.

Principle 10.1 of the Council’s Residential Design Guide Supplementary Planning Document (SPD) 2017 advises that extensions are expected to be subordinate and consistent with the form, scale and architectural style and materials of the original building. I accept that this does not preclude the incorporation of contemporary additions and that the proposed dormer has been reduced in width and depth from the previous scheme. Nonetheless, it would still only be slightly offset from the ridgeline and, due to its positioning, would effectively result in a stacking of features, leading to a cluttered and contrived appearance. As such, I find that the dormer additions would be an unsympathetic and dominant addition.

As the proposed development is to the rear elevation, it would not be visible in the street scene. Nevertheless, as expressed in the previous appeal decision, this does not negate the need for good design. [name] acknowledge the amendments which have been made, the proposed dormer addition would fail to harmonise with and would be out of keeping with the character and appearance of the host property.

The proposed development would therefore fail to accord with policy DM9 of the [name] and Development Management Policies 2011-2028 (CSDM), February 2012 and the [name] 2017, which require high-quality design which, amongst other things, respects and enhances local character.

The windows in the dormer are proposed to be obscurely glazed, which would result in no outlook from the room being created in the roof space. Notwithstanding the appellant’s proposed use as a games room, as the previous appeal decision notes, the room could also be used as a bedroom, and the use of rooms within a property, and its occupiers may change.

While recognising that the obscure glazing is to address concerns regarding overlooking, and that such provisions for a specific window are a common way of managing potential privacy issues, the proposal with the entire structure only including obscurely glazed windows contributes to the poor design and contrived nature of the addition.

I therefore find that this adds to the conflict with CSDM policy DM9, with criterion (iii) requiring development to respect the amenities of occupiers and those of the neighbours. There would also be associated conflict with the provisions of the SPD and the Framework, which seek to ensure a high standard of amenity for existing and future users.

The appellant has proposed the addition of roof lights to the front elevation. While this might enhance the internal environment, it does not resolve the other design concerns, and therefore, it cannot be addressed through a condition.

For the reasons set out and having regard to all other matters raised, the appeal is dismissed.