Appeal 3337623

The appeal is dismissed insofar as it relates to the single storey front extension, single storey rear extension and partial garage conversion.

The appeal is allowed, and planning permission is granted insofar as it relates to the side dormer, and enlargement and alterations of existing front and rear dormers at [site address] in accordance with the terms of the application, 23/02493, dated 9 October 2023 and the plans submitted with it.

The proposed development has been constructed. It is therefore a retrospective proposal and I have dealt with the appeal on that basis.

The main issues are the effect of the development on the character and appearance of the host property and the surrounding area, and flood risk.

The detached bungalow to the southern side of [address] forms part of a group of similar hipped roofed properties with a dormer window to the front. The positioning of the additional dormer windows to the appeal property echoes those to No.6 adjacent. The Council have raised no objection to this aspect of the proposal and from the information before me and my observations on site I have no reason to disagree.

Extending across the full width of the property, including the existing garage to the side, the rear extension has a significant width. However, the single storey, flat roof structure has a limited height, and set within a generous plot the resultant property does not appear disproportionate or cramped.

The extension does not align with the eaves of the host property and creates a step-in height to the structures along the side of the property. Although, this is not overly discernible in general views along the road, and I do not find that the extension has an incongruous relationship with the host property. It was also evident from my site visit that other properties have extensions or garages set back to the rear of the property. This includes the immediate neighbour (No.6), which has a rear extension, albeit less deep, which has a similar relationship with the eaves line of the bungalow.

Principle 10.1 of the Council’s Borough Wide Design Guide 2020 (BWDG) does not include any specific size limitations for extensions, and the proposal accords with the provisions to be subordinate and for the materials to match. Overall, and particularly in relation to the street scene, the original bungalow prevails, and I do not find that the extension is of a scale or unsympathetic form to be visually prominent or harmful to the appearance of the host dwelling.

I, therefore, conclude that the development would be appropriate for the character and appearance of the area and complies with policy QP 3 of the Royal Borough of Windsor and Maidenhead Borough Local Plan 2013-2033 (BLP) and policy DAT.2 of the Datchet Neighbourhood Plan (NP). Together these support high-quality design that respects the local environment. In that regard, there would also be compliance with the design aspects of the National Planning Policy Framework (the Framework) and the BWDG as a whole.

The site is located within [name] 3. As such a flood risk assessment is required in accordance with policy NR 1 of the Borough Local Plan (2013-2033) and the Framework (footnote 59). No flood risk assessment or any associated information was submitted as part of the planning application or this appeal.

The assessment is normally required before the commencement of development to establish whether the principle is acceptable and to identify mitigation measures. In this case, while the extensions have been built, there are no details before me that indicate appropriate provisions have been incorporated or that they could be accommodated within the development as built to safeguard from flooding over its lifetime. Given the lack of information and the uncertainty of any associated mitigation, this cannot be secured by

The development therefore conflicts with policy NR 1 of the Local Plan and the Framework which seeks to ensure development is not at risk of flooding or would increase flood risk elsewhere.

I have found that the development would not be harmful to the character and appearance of the property, however, due to potential flood risk the extensions cannot be supported. The dormer windows relate to an existing first-floor bedroom and do not alter the footprint of the building or its use. As such, I do not consider that this aspect of the development would affect the flood risk of the existing property. As the dormer windows are already in situ and are independent features, they are severable from the ground floor alterations and under section 79 of the Town and Country Planning Act 1990 I have expressed powers to split a decision.

For the reasons set out above, I conclude that the appeal should be allowed in respect of the dormer windows, but due to the lack of a flood risk assessment, the extensions and other alterations are to be dismissed. As the dormer windows have already been constructed no conditions are necessary.