Appeal 3355581

The appeal is allowed and planning permission is granted for the erection of a single-storey side, part single, part double rear extension, and loft conversion with 2 No side dormers at [site address] in accordance with the terms of the application, [name]/17891/006, and the plans submitted with it, subject to the following conditions:

The windows hereby permitted in the flank walls at first and second floor levels shall be retained hereafter glazed in obscure glass and shall be non-opening below a height of 1.7 metres measured from the internal finished floor level, as shown on [name]-01 Rev P2 and PL-02 Rev P2.

Notwithstanding the provisions of the Town and Country Planning (General Permitted Development) (England) Order 2015 (or any order revoking and re-enacting that Order with or without modification), no windows other than those expressly authorised by this permission shall be constructed on the flank elevation of the development hereby permitted.

The roof area of the single-storey rear extension hereby permitted shall not be used as a balcony, roof garden or similar amenity area.

The application was made retrospectively. At the time of my visit I saw that the development was complete.

There is some extensive planning history to the appeal property. Prior approval was given in November 2020 for the erection of a 6m deep single-storey rear extension as permitted development ([name]/17891/001). [name] 2021, a certificate of lawful development was issued for works described as ‘hip to gable loft conversion with 2no side dormers and 1no front velux window’ ([name]/17891/005). [name] 2021, planning permission was granted for development described as ‘Construction of single storey side extension and part single/part double storey rear extension and demolition of existing garage’ ([name]/17891/003).

The works that have been implemented, and which are the subject of the appeal, are an alternative amalgam of these past decisions.

The Council has raised no concern with regard to the size, scale or appearance of the single-storey side extension or the part single, part double rear extension parts of the proposal. Given the planning history I have no reason to disagree. The main issue therefore is the effect of the development upon the character and appearance of the street scene, with particular regard to the accumulation of additions at roof level.

The appeal property is a detached, two-storey dwelling within a row of detached and semi-detached houses of broadly similar age but with some variation to their appearance that are fairly prominent within the street scene. The property falls within a stretch of [address] that is defined as a residential area of exceptional character by Policy H12 ([name] of [name]) of The Local Plan for Slough, adopted in March 2004 (LP). The policy states that development proposals will not be permitted within the defined area which would have a detrimental impact upon the character and amenity of residential units, specifically extensions which would change the scale and nature of the property.

The development has undeniably altered the form and shape of the dwelling’s original roof. Its hipped form has been subsumed by a front facing mono-pitch that masks large, tile clad dormers to each side which sit only marginally up from the eaves and which span the full depth of the original dwelling. These both sit behind a false ridge line, which runs parallel to the road, and merge with each other to form a square flat crown roof that sits marginally taller than the dwelling’s original ridge height. The two-storey extension to the rear projects the original height and form of the dwelling with a conventional hipped roof.

The Council’s Residential Extensions Guidelines Supplementary Planning Document (SPD) was adopted in 2010. Its stated purpose is to principally provide additional guidance on how to interpret and implement Core Policy 8 (Sustainability and the Environment) of the Slough Local Development Framework Core Strategy 2006 – 2026 (CS) when assessing residential extensions. SPD paragraph 1.2.6 states that the ultimate aim of the guidance is to ensure that the residential areas within Slough remain good places to live and are not adversely affected by inappropriate extensions. Specifically, [name] 3 (DP3) advises that extensions should be subordinate and in proportion to the original house without dominating the original building.

The SPD deals with two-storey/first-floor rear extensions at section 7.0 and roof extensions/dormer windows/roof lights at section 8.0. Its detailed design guidance at EX29 states that the roof of a two-storey rear extension must respect the original roof form of the house and that flat roofs will not be acceptable. With regard to roof extensions, detailed design guidance at EX33 and EX34 states that alterations that change the shape and/or pitch to the main roof of the house, or by raising the ridge line will not normally be permitted. Further, that dormer windows will normally only be permitted on the rear of a building and should be in proportion with the size of the original roof. Specifically that they should have a minimum set down of 0.5m below the main ridge, a minimum set in distance of 1m at either end of the main roof slope on which they sit, a minimum 1m set above normal eaves level, and that they must not occupy more than 50% of the width of the existing roof slope on which they sit.

The changes to the form and height of the front roof slope combined with the size and scale of the side dormers and the resulting crown roof, including from part of the building’s rearward extension, significantly breach the SPD’s guidance at EX29, EX33 and EX34. The alterations cannot reasonably be considered to be subordinate, proportionate, or sympathetic to the form of the original dwelling, which has been significantly remodelled as a consequence of the works.

However, when seen directly face on from [address], the dwelling has the appearance of a traditional gabled form with a subordinate retained hipped feature over its original two-storey front bay. This merely reflects hip to gable changes that are evident on other properties nearby, including immediately adjoining at No 240, where I saw the symmetry of an original semi-detached pair had been disrupted by such a change. Despite the marginal increase to the ridge height at No 242, the front roof appears neither disproportionate nor out of keeping within the street scene.

The side dormers are openly seen as large roof additions in angles of vision from [address], but each from only limited viewpoints between the fairly narrow gaps between both neighbouring properties. Moreover, I am mindful of the size, scale, form, and visual impact of the dormers that were confirmed as permitted development in April 2021. If constructed, these would have had a significant impact upon the shape and appearance of the original dwelling. I accept that judgements over appearance were not part of the Council’s consideration when the certificate of lawfulness was issued, but I attribute significant weight to the fallback position that it established. Furthermore, despite the scale and somewhat unorthodox approach that has been adopted for the roof extensions, I share the appellant’s view that the result is an aesthetically more pleasing and balanced change when compared with two exposed side dormers that would have been set equally just up from the eaves and which would have been openly seen to dominate the side slopes of the original roof.

Overall, despite the identified conflicts with the SPD, having regard to the background and specific circumstances at No 242, I am satisfied that the development appears as a reasonably integrated addition that is neither visually intrusive nor harmful to the character or appearance of the appeal property or wider area. As such, I find no conflict with Policy H12, or the similar requirements reflected by [name] H15 ([name]), EN1 (Standard of Design) and EN2 (Extensions) and part 2 of CS Core Policy 8, which between them seek to ensure that all development displays a high quality of design that is respectful of, and compatible with, its surroundings. For the same reasons there is no conflict with the National Planning Policy Framework’s aims and objectives for achieving well-designed places.

I note a neighbour’s comment regarding the introduction of flank windows at first and second floor levels, and associated disturbance from noise and light. However, the fenestration pattern as built resembles closely that which either formed part of the originally approved extensions to the appeal property, or those that could be built as permitted development. Moreover, the plans show all first and second floor flank windows to be obscurely glazed and fixed shut up to a height of 1.7m above finished floor level. I share the Council’s view that this would avoid any impact upon any neighbouring occupiers’ living conditions that would be harmful. I am not persuaded that any light spillage from flank windows would mutually impact any neighbouring living spaces to a degree that would be harmful.

I note a neighbour suggestion that the premises are being used as a care home. There is also reference to this in the officer’s report. However, the application for the extension works was retrospective and was made as a householder application for planning permission for extension to a dwelling. Furthermore, the application form stated that the works were started in May 2021 and completed in November 2023, and I also note the officer’s report, dated October 2024, stated that, at that time, the property was currently used as a detached family house. I have no substantive reason not to consider the appeal based on how the application was submitted and determined by the local planning authority.

Given that the application was made retrospectively, there is no need for me to impose the standard time limit permission or one that would require works to be carried out with matching materials.

To safeguard the living conditions of neighbouring occupiers, I have imposed a condition that would require the glazing of the new first and second floor flank windows to be retained with obscure glazing and fixed shut up to a height of 1.7m, as shown on the submitted plans. For the same reason, I agree with the Council that conditions are also required to prevent any further windows being installed in the flank elevations of the extensions hereby permitted at first and second floor levels, and that any outside use of the flat roof over the single-storey rear extension should be prohibited.

For the reasons given above, the appeal is allowed.