Appeal 3317229

The appeal is allowed and planning permission is granted for a single storey rear extension, roof extension with dormer windows together with external garden landscaping works, installation of solar panels and air source heat pumps following demolition of existing conservatory, at [name], [address] Horsley, [site address] [postcode] in accordance with the terms of the application Ref 22/P/01239, dated 14 July 2022, subject to the following conditions:

The development hereby permitted shall begin not later than 3 years from the date of this decision.

The development hereby permitted shall be carried out in accordance with the following approved plans: 1981-(01)001; 1981-(01)002; 1981- (01)101; 1981-(01)102; 1981-(02)000; 1981-(02)001; 1981-(02)002; 1981-(02)100; 1981-(02)101; 1981-(02)102; 1981-(04)001; 1981- (04)002; 1981-(04)003; 1981-(04)004; 1981-(04)101; 1981-(04)102; 1981-(04)103; 1981-(04)104; 1981-(05)001; 1981-(05)002; 1981- (05)101; 1981-(05)102.

The materials to be used in the construction of the external surfaces of the development hereby permitted shall match those used in the existing building.

In the formal decision, I use the more detailed description of development given on the decision notice and appeal form but substituting ‘roof extension’ for ‘loft conversion’ as this more accurately describes the works.

The site lies within the Green Belt. Therefore, the main issues are: • Whether the proposal amounts to inappropriate development in the Green Belt, including the effect on the openness of the Green Belt and the purposes of including land within it; • The effect of the proposal on the character and appearance of the area; • If the development is inappropriate, whether any harm by reason of inappropriateness, and any other harm, is clearly outweighed by other considerations so as to amount to the very special circumstances necessary to justify it.

Paragraph 149 of the National Planning Policy Framework (September 2023) (the Framework) states that the construction of new buildings within the Green Belt is inappropriate development but lists certain forms of development which are not regarded as inappropriate. This includes the extension or alteration of a building provided that it does not result in disproportionate additions over and above the size of the original building. Policy P2 of the Guildford Borough Local Plan: Strategy and Sites (April 2019) (the LPSS) confirms that Green Belt policy will be applied in line with the Framework.

The appeal dwelling is a 1950s bungalow which has been added to through a loft conversion with dormer window, a single storey utility room and a conservatory. The conservatory would be replaced with an infill extension between the living room and utility room. At first floor level, the lowest part of the roof at the garage end of the dwelling would be raised and extended rearward over the flat-roofed utility room. Three dormer windows would be inserted in the rear roof slope, with rooflight and photovoltaic panels added to the front roof slope.

The Council sets out that the proposal, when taken together with existing additions including the space created by the loft conversion, would result in a 71% increase in floorspace compared to the original building and amount to disproportionate additions. The appellant’s measurements suggest an increase of around 80% GEA or 58% GIA if the loft space is considered an extension, but 23.2% GEA or 35% GIA if the loft space is deemed to form part of the original floorspace.

Neither the Framework nor the development plan specifies what might be a disproportionate addition over and above the size of the original building. Therefore, the assessment of whether the proposal would amount to ‘disproportionate additions’ is ultimately a matter of judgement based on the particular facts in each case. The appellant points to other proposals for extensions within the Green Belt where increases of between 62% and 120% were permitted by the Council, but I have no further detail of these schemes, including whether the stated increases relate to floorspace, footprint or volume. Therefore, they are not decisive to my considerations.

The differences in the main parties’ figures reflects the difficulty in assessing whether a proposal is disproportionate solely on the basis of floorspace, as it is possible to create significant additional living space within the roof space without materially increasing the overall footprint or volume of the building. Given the purposes of the Green Belt to maintain openness, it strikes me that the assessment must also consider differences in footprint and volume to reach an overall view on whether the proposals would amount to disproportionate additions.

The parties have not provided me with measurements in these respects, but from the appellant’s marked up plans, it is evident that the dwelling has not been subject to significant increases in either external footprint or volume from the utility and conservatory extensions and the modest rear dormer. Having also observed these extensions on site, I find they have not contributed to disproportionate additions over and above the original building.

The proposal would replace the conservatory with an infill extension of similar overall area, such that the overall footprint of the dwelling would not change significantly. In terms of volume, the roof would be enlarged, but in a limited and considered manner that would maintain the hipped roof design. The dormers would also sit within the rear roof slope and would maintain the overall height and shape of the roof. Overall, the proposed works would not significantly increase the scale of the building, which would still clearly read as a dormer bungalow on effectively the same footprint.

For these reasons, I find that the existing and proposed extensions, taken together, would not result in disproportionate additions over and above the size of the original building. Therefore, the proposal would not amount to inappropriate development in the Green Belt and would not conflict with the relevant provisions of the Framework or Policy P2 of the LPSS.

Given my findings that the proposal would not be inappropriate development in the Green Belt, the proposal would, by definition, not have an adverse impact on the openness of the Green Belt or the purposes of including land within it. Moreover, as the proposal does not amount to inappropriate development, there is no requirement to assess if there are other considerations that amount to very special circumstances needed to justify the development.

The Council’s concerns relate only to the proposed flat-roofed dormer windows to the rear. These would be quite large in size, having a slightly vertical emphasis with large, casement window openings. The Council’s Residential Extensions and Alterations Guide Supplementary Planning Document 2018 (SPD) generally discourages flat-roofed dormer windows on the front elevation and where the original dwelling has a pitched roof.

The proposed dormers would not reflect this guidance, but they would accord with the SPD in that they would not effect a significant change to the height or form of the roof, being set well below the main ridge line, above the eaves and inset from the edges of the roof. Despite their size, the dormers would still be proportionate in scale relative to the overall roofscape and there would be no discernible impact on the appearance of the dwelling from the front. I am also satisfied that the windows would not appear oversized compared to the ground floor, which would contain several wide windows and doors creating an expansive, open appearance to the rear elevation.

Moreover, the dwelling stands as part of a circular layout around a turning circle at the head of a cul-de-sac. As a result, the rear elevations of dwellings angle away from each other and face out over open agricultural fields. This orientation of dwellings, coupled with the tall, established hedging to the side boundaries of the site, mean that neighbours would have no clear view of the dormer windows from within their dwellings or rear gardens.

Elsewhere, the increased ridge height and roof volume would rationalise the roof form on this side of the dwelling, without altering its overall form. The proposed rooflights and photovoltaic panels to the front roof slope would similarly maintain the overall form of the roof and dwelling as a whole. Given the recessed position of the dwelling in its plot, and the screening provided by the boundary hedgerows, the alterations would have limited visibility in what is an eclectic context of individually designed dwellings, some considerably larger in scale and more prominent than the appeal dwelling.

The appellant refers to the Inspector’s assessment of proposed rear dormer windows in an appeal decision1 from 2021. Whilst noting the considerations made, this decision relates to a different development in a separate location, and as such is not comparable to the scheme before me. Therefore, this has not attracted significant weight in my own assessment, which I have undertaken with regard to the specific planning merits of the proposal.

For the above reasons, I conclude that the proposals would preserve the character and appearance of the area, in accordance with Policy D1 of the LPSS and saved Policy G5 of the Guildford Borough Local Plan 2003 (saved September 2007) (the GBLP), which together require development to achieve high quality design that responds to the distinctive local character of the area. The proposal would also accord with the similar aims of the Framework and with the general aims of the guidance contained in the Council’s SPD.

The Council did not refuse permission in respect of neighbours’ living conditions. The proposed windows would be screened by boundary hedgerows and would face the appellant’s own garden. No harmful overlooking of neighbours would therefore occur, and the works would not add any significant height to the dwelling that would cause harmful overshadowing or enclosure.

The proposal would not be inappropriate development in the Green Belt, nor would there be a harmful effect on the openness of the Green Belt or the character and appearance of the area.

Consequently, there is no conflict with the development plan or the Framework and the appeal should succeed, subject to a condition requiring development to be carried out in accordance with the approved plans, to provide certainty; and a condition requiring materials to match those used on the existing dwelling to ensure a satisfactory appearance.

The appeal is therefore allowed.