Appeal 6004220

The appeal is dismissed.

The main issues are the effect of the proposed development on: • the character of the host dwelling and street scene; • living conditions of the occupiers of [address] of outlook; and • the risk of flooding.

The appeal site lies in a residential suburb extending from the historic village core of Wraysbury towards the [name]. [address] principally features large, detached dwellings set in long rectangular plots. There is a relatively wide variety of dwelling forms with bungalows, chalet bungalows and two storey dwellings using predominantly brick and render finishes. Siting is consistently to the front parts of the plots with similar building lines. Frontage areas typically provide off road parking and some garden space, creating a spacious and well-maintained setting. Dwellings tend to utilise the width of their plots, building up to the boundary in some cases although the majority retain sufficient spacing to allow access to the rear. Mature trees, hedgerows and shrubbery contribute to a pleasant street scene.

The appeal site itself is typical of this locality, comprising a chalet style two storey dwelling including front gable, with a linked garage up to the side boundary and gravelled parking area to the frontage space. The proposed two storey side extension would continue both the primary roof ridge height and front elevation building line, bringing the built form significantly forward from the recessed siting of the current garage and ‘filling-in’ the space between the dwelling and the side boundary to the full height of the dwelling.

The neighbouring property, no [address], also comprises a two-storey chalet bungalow of differing form, positioned further forward and close to the shared boundary so that the spacing between the two dwellings would be significantly reduced. Whilst the appeal property would remain physically detached, with retained spaciousness to the front of the dwelling and within the length of the rear garden, the reduced space to the side would intensify the built form to the detriment of the appearance of the site.

I am directed to the example of no [address] which demonstrates a two-storey side extension up to the site boundary. The council advises that this development predates the current development plan and supplementary planning document and would fail to meet policy requirements in the current context. I do not have sufficient details before me to establish the degree of comparability and as such, this example bears limited weight in my decision.

The rear extension would also continue the primary ridge height and create a roofscape formed of three gables connected by high level flat roofed sections and differing eaves heights at each end. The single storey rear extension would introduce a flat roofed structure for the full width of the extended dwelling.

The side extension would necessitate the loss of an existing chimney and be fully visible to the public realm without any reference to subservience to the host dwelling, thereby undermining its original character and appearance and the quality that it contributes to the site and street scene in this locality. The rear development would result in scale, form and detail that would completely alter the original dwelling to the detriment of its character and appearance. Given the positioning of the existing houses, visibility of the rear of the site would predominantly fall to surrounding dwellings, however, this is not justification for the harm generated to the rear elevation and the site as a whole.

Whilst the locality demonstrates a variety of building forms and details, the policy requirement and use of design principles is not to homogenise the street scene or to enable any design solution but to reinforce the positive design features of each individual dwelling in its particular context. This approach is consistent across the development plan and accompanying supplementary planning and national planning guidance. The National Planning Policy Framework (2024) (NPPF) paragraph 139 confirms that significant weight should be given to development which “reflects local design policies and government guidance on design, taking into account any local design guidance and supplementary planning documents...” and that development that is not well designed should be refused.

The application of design principles and guidance provides direction towards the important components of high-quality design, and whilst each point might not be determinative in a context, the effect upon a site and surrounding area is informed by the accumulation of design decisions and overall approach. In this instance, the enlargement of the property is proposed in a manner that does not sufficiently respect the character and appearance of the host dwelling by way of scale, form, siting and design details.

For these reasons, the proposed development would be materially harmful to the character and appearance of the host dwelling and street scene, contrary to Policy QP3 of the Royal Borough of Windsor & Maidenhead Borough Local Plan 2013 – 2033 (the Local Plan) which expects new development to achieve sustainable, high quality design, respecting and enhancing local character, including in relation to scale, bulk, massing and proportions.

It would also be contrary to Section 10 of the Royal Borough of Windsor & Maidenhead Borough Wide Design Guide Supplementary Planning Document (2020) (SPD) which requires extensions to be subordinate and sympathetic to the host dwelling and Chapter 12 of the NPPF which seeks to ensure that development is visually attractive and sympathetic to local character.

No. [address], adjacent to the appeal site, would see the existing garage positioned along the shared boundary replaced by a part two-storey flank elevation and projecting single storey elevation. No. 37 itself features a single storey rear wing extension to the other side of the property so that the garden close to the rear of the dwelling is already surrounded by built form to a degree. The two-storey extent of the proposed development, projecting beyond the primary rear building line of no. 37, in conjunction with the extended single storey elevation beyond that of the existing garage would exacerbate this sense of enclosure, reducing the openness of the rear garden and resulting in a detrimental impact on the outlook of the occupiers of no. [address].

As such, the proposed development would result in unacceptable harm to the living conditions of the occupiers of no. [address] contrary to Policy QP3 of the Local Plan in so far as it seeks high quality design and high quality amenity space.

In addition, the proposed development would be contrary to the SPD which specifically requires no unacceptable effect on the amenities enjoyed by the occupants of adjoining properties and Chapter 12 of the NPPF which requires a high standard of amenity.

The appeal site is located within Environment Agency (EA) fluvial flood zone 3 associated with the nearby [name]. The residential use of the site qualifies the proposed development as ‘more vulnerable’ to flood risk. The NPPF states that all development should be safe for its lifetime and shouldn’t increase flood risk on the site or elsewhere.

Paragraphs 176 and 181 of the NPPF, in conjunction with footnotes 62 and 63 make clear that whilst householder development is not subject to either the sequential test (for location of development) nor the exception test (to justify exceptional circumstances), all development in flood zones 2 and 3 is required to be supported by a site-specific Flood Risk Assessment (FRA). The EA provides standing advice on flood risk for development comprising minor extensions in order to comply with NPPF requirements and Planning Policy Guidance (PPG) states that FRA needs to be appropriate to the scale, nature and location of the development.

The appellant’s FRA has been authored by a specialist company citing appropriate technical accreditations. It acknowledges that the site is within flood zone 3 with a high probability of flooding, notes all potential sources of flooding and provides recommendations for how the development can take such risk into account. It identifies the existing ground level of the proposed development footprint as ranging from 16.10mAOD-16.40mAOD and with a proposed uniform [name] of approximately 16.65mAOD. The FRA has been based upon the highest 1 in 100-year plus 35% [name] floodplain level at the site (17.64mAOD) which indicates that the development area may experience depths of between 1.24m and 1.54m during a 1 in 100-year (+35%) climate change event. Risk from groundwater flooding is identified as being >= 75% within the locality and risk from reservoir failure is also noted. The surface water drainage provision is identified as potentially needing to be updated due to infrastructure being located under the proposed footprint of the scheme. Flood resistance and resilience measures are recommended to protect the development, and these could be secured by planning condition.

Based upon the evidence before me therefore, the FRA provides the information required by the EA and subject to the imposition of conditions, the proposed development could be completed in a way that would comply with Policy NR1 of the Local Plan which amongst other things, seeks to ensure that development should not itself, or cumulatively with other developments materially cause new or exacerbate existing flooding problems, either on the appeal site or elsewhere. Similarly, based upon the submitted evidence, the proposal complies with Chapter 14 and specifically paragraph 181 of the NPPF which provides for an FRA to ensure that development can be made safe in terms of flood risk.

The proposed development would incorporate photovoltaic panels to the roof in line with development plan and NPPF ambitions towards a low-carbon future. This represents a benefit in support of the scheme however is not sufficient to outweigh the harm I have identified above.

For the reasons given above the appeal should be dismissed.