Appeal 6002193

The appeal is dismissed.

The site visit was undertaken by a representative of the Inspector whose recommendation is set out below and to which the Inspector has had regard before deciding the appeal.

The effect of the proposed development on the character and appearance of the host dwelling and wider area, the living conditions of the occupiers of [address], with particular regard to outlook and sunlight, and highway safety.

The appeal property is a semi-detached dwelling within a residential street characterised by a strong and largely uniform building line, simple pitched-roof forms and extensions that, where present, generally remain visually subordinate to the host dwellings. Although alterations and rear extensions exist within [address], the prevailing character is one where the principal roof form remains dominant, and rear additions are typically read as secondary elements when viewed from surrounding properties. The original dwelling at No 114 retains a modest rear projection and a traditional roof profile that reflects the scale and proportions of the host building.

The proposed dormer would span almost the entire width of the rear roof slope and would only have a slight set down from the ridge. The pitch roof of the proposed two storey extension would adjoin the dormer window. The differing roof heights and designs would have a convoluted appearance which would be at odds with the simplicity of the existing rooflines within the street scene. It would also interact poorly with the host dwelling resulting in a top heavy and bulky appearance that would be visually dominant. Whilst public views from [address] would be relatively limited, the resulting form would be highly visible from neighbouring Appeal Planning Officer 6002193 gardens, where it would appear incongruous within the established pattern of development.

The appeal scheme would therefore fail to preserve the character and appearance of both the host dwelling and the surrounding area, conflicting with Policies CP1 and CP12 of the Three Rivers District Council Core Strategy (2011), Policy DM1 and Appendix 2 of the Three Rivers District Council Development Management Policies Local Development (2013), as well as the National Planning Policy Framework.

The appeal site forms part of a semi-detached pair, adjoining No 116 and adjacent to No [address], both of which rely on rear-facing room windows to obtain outlook and daylight across their respective gardens. In their current form, the dwellings sit within a spatial arrangement that allows neighbouring rear windows to retain an acceptable outlook and access to daylight over their respective gardens.

No 116 includes an existing single-storey rear extension which is built up to the shared boundary with the appeal site and is partially screened by an established boundary hedgerow. No 112 is set approximately 1 metre from the shared boundary with the appeal site and has a more modest rear projection in the form of a conservatory.

The appeal proposal would introduce a single-storey rear extension extending approximately 6 metres from the rear elevation of the host dwelling and spanning the full width of the plot, built up to both side boundaries. Whilst the proposed two-storey rear extension would not project the entire depth of the single storey extension, it would extend beyond the rear elevations of both neighbouring dwellings.

In relation to No 116, the single-storey element would broadly reflect the depth of existing rear projections and, in isolation, would not result in a significant loss of light to ground-floor windows. However, the proposed first-floor rear extension would be positioned in close proximity to a rear first-floor window. Due to the scale, depth and height of this element, combined with its close proximity to the window the first floor extension would appear unduly prominent and overbearing when viewed from the window, resulting in harm to outlook.

With regards to No 112, the introduction of the full-width, single-storey extension built against the boundary would introduce a substantial increase in bulk adjacent to a property that is currently set away from that boundary. Combined with the two-storey rear extension the proposal would significantly reduce the outlook currently experienced by No 112. Further, the height and mass of the proposed extension would make the development overly dominant and oppressive for the occupiers of No

It would lead to a gloomy living environment and result in unacceptable loss of outlook from their rear windows and garden area. While the use of a hipped roof would provide some reduction in mass, it would not sufficiently mitigate the cumulative effect of the combined first and second floor extensions.

Taken together, the scale, depth and proximity of the part single-storey, part two-storey rear extension would result in a development that appears overbearing and unneighbourly when experienced from adjoining properties, particularly No 112, leading to a material loss of outlook and daylight. The proposal therefore fails to Appeal Planning Officer 6002193 safeguard residential amenity and is contrary to Policies CP1 and CP12 of the [name] (2011) and Policy DM1 and Appendix 2 of the Development Management Policies (2013).

Concern has been raised by the Council that the proposed development could facilitate the use of the property as a four-bedroom dwelling, which in turn could increase parking demand in an area where on-street parking availability is already limited.

However, based on the evidence before me, the proposal does not explicitly include works that would definitively result in such a change in the number of bedrooms, and no substantive evidence has been provided to demonstrate that the development would, in practice, function as a materially larger dwelling of that nature. As such, any assessment of increased parking demand arising from a potential intensification of use is, at this stage, speculative.

[name] acknowledge that parking stress in the surrounding area appears to be constrained, the absence of clear and convincing evidence linking the proposed development to a measurable increase in vehicle movements or parking demand means that I cannot conclude that the scheme would give rise to harm to highway safety.

. Accordingly, I find that the proposal would have a neutral effect on highway safety and therefore complies with Policy CP10 of the Three Rivers District Council Core Strategy (2011) and Policy DM13 of the Three Rivers District Council Development Management Policies Local Development (2013).

The prior approval granted under reference 25/0708/PDE for a single-storey rear extension has also been considered. It is acknowledged that this consent is capable of implementation and therefore represents a theoretical fallback position. However, the appeal proposal differs materially from the development authorised under that prior approval. In particular, the appeal scheme involves a full‐width rear extension and the introduction of a two‐storey rear extension and roof alterations, none of which formed part of the prior approval and none of which could be assessed through the permitted development process.

Furthermore, the prior approval was not subject to a detailed assessment of impacts on neighbouring residential amenity. When assessed as a whole, the appeal proposal would give rise to materially greater impacts in terms of bulk, massing and proximity to neighbouring dwellings than the development permitted under the prior approval. As such, limited weight is attached to the fallback position in this case, and it does not outweigh the harm identified.

For the reasons given above, and having taken all other matters into account, the proposal would conflict with the development plan when read as a whole. There are no material considerations sufficient to justify a decision other than in accordance with the plan. Appeal Planning Officer 6002193

I have considered all the submitted evidence and my representative’s report and on that basis the appeal is dismissed.