Appeal 3269647

The appeal is dismissed.

The description of development as stated on the application form is set out above. The Council, on the decision notice, has described the development as “Erection of a first floor extension to existing garage to provide ancillary annexed accommodation to the main dwellinghouse with provision of external staircase to rear”. This more accurately describes the proposals as shown on the plans and I have considered the appeal on this basis.

Since the submission of the appeal, the National Planning Policy Framework from 2019 has been replaced, with the new version being published in July 2021 (the Framework). Amongst other changes, Section 12 has been amended to reflect the new National Model Design Code. Nevertheless the character protection aims of both local policy and the Framework are similar and so neither party has been prejudiced by this change in policy circumstances.

The main issues are: • Whether the proposal would be inappropriate development in the Green Belt having regard to the National Planning Policy Framework (the Framework) and any relevant development plan policies and the effect on the openness; • The effect of the development on the character and appearance of the area; • Whether the harm by reason of inappropriateness, and any other harm, would be clearly outweighed by other considerations so as to amount to the very special circumstances required to justify the proposal.

The Framework states that development within the Green Belt is inappropriate unless it falls within one of the exceptions set out in paragraphs 149-150 of the revised Framework. These exceptions include the extension of a building, so long as this would not result in disproportionate additions over and above the size of the original building.

The appeal site is the existing garage detached from and located to the side of the existing detached dwelling. The garage building is single storey with a mono-pitched roof, with access for cars to the front, windows to the side and rear walls and a rear personnel door. The proposed development would introduce an extension to the existing single storey garage to the side of the house, creating a pitched roof with dormer windows to the front elevation. There would be access to the first floor of the extension via an external staircase as well as being a link to bedroom 2 of the main house at first floor level. The ridgeline of the extension would remain below that of the main dwelling, with materials to match the main house and existing garage. The intended use of the building is stated to be ancillary accommodation to the main house.

Policy 24 of the Sutton Local Plan1 (the Local Plan) reflects the Framework, stating that proposals for extensions to existing buildings would be permitted where the increase in the external volume of the built form is no greater than 30% above the size of the original building or structure. The supporting notes to this policy says that this figure should only be treated as an indication and that the Council will also consider the mass, scale and any increase in ridge height in order to determine if an extension is disproportionate. The Local Plan also clarifies that the ‘original building or structure’ includes garages within 5 metres of a dwelling when first built and that a disproportionate addition could occur through one large extension or through the cumulative impact of a series of small ones.

The Council calculates that the original dwelling was approximately 509.8 cubic metres and that proposed extension together with previous additions would result in a cumulative additional extension to the dwelling and garage of a total of 452.65 cubic metres. This would increase the original dwelling by about a total of 88.7%.

I note that on the whole, the proposal would make use of the existing footprint area of the garage building, nonetheless the bulk and scale of the additions over and above the existing garage and dwelling would result in a dominant and disproportionate addition to the original. The figures provided by the council show a significant volume increase above the guide of 30% as set out in Policy 24, and demonstrates a disproportionate addition over and above the original. 1 Sutton Local Plan 2016-2031 (2018)

Whilst the house is set back from the street frontage, the site is easily visible and the increase and bulk of development would be easily visible from the street. The dwelling is located in a row of similar properties of similar age and appearance, with some variations in details and arrangements. Even so, the overall appearance is one of similar detached dwellings with uniform window arrangements and even spacing between dwellings. The proposals would introduce a bulky and dominant element at first floor level adjacent to the new house, creating the effect of another significant building attached to the main house. I accept that the proposed development would remain below the main ridgeline of the house, with the same roof profile and be constructed of similar materials to the existing, nevertheless the added bulk and dominance of built form in this location within the Green Belt would result in a discordant effect on the streetscene and significant harm to the openness.

By reason of the bulk and scale of the proposed development, and the significant extension to the dwelling and garage beyond the extensions which have already taken place, I conclude that the proposal represents disproportionate additions over and above the size of the original garage building and dwelling and therefore would be inappropriate development in the Green Belt, causing significant harm to the openness. [name] accept that the proposal makes use of the existing site and remains within the curtilage of the existing property, I do not consider that these factors outweigh the harm to the Green Belt or its openness as identified.

The proposal would conflict with the provisions of the Framework, as well as Policy 28 of the Local Plan. When considered as a whole, the spatial impact of the development means that it would clearly fail to preserve the openness of the Green Belt. This adds to the harm resulting from being inappropriate development in the Green Belt.

The development would introduce a large addition to the garage building and would create a two-storey building. I accept the appellant’s contention that the proposal would make use of the exiting garage footprint, the development in combination with the existing dwelling would create a significant and dominant addition which would inherently change the character and appearance of the dwelling and the local area.

The appeal site is located at the end of a row of houses, part of which the overall character is their uniform appearance and layout. This includes, as described previously, their materials and layout of detached houses with ancillary garages. I accept that there have been additions or alterations however these do not detract from the overall character and appearance of the original houses as a whole. In contrast, the proposed development would result in a dominant addition and alteration which would change the character and appearance of the host dwelling and as such the local area.

The materials are to match the existing dwelling and so there is some association to the main house, however the extent of the design introduces a bulky and dominant addition. I conclude that there is an unacceptable interruption to the pattern and grain of the character and appearance of the area.

The appellant has pointed out that there have been a number of other additions and alterations to other properties along [site address] . The circumstances in each proposal are likely to be different, and in any event the fact that apparently similar extensions may have been permitted is not a reason, on its own, to allow unacceptable development. I have considered this appeal proposal on its own merits and concluded that it would cause harm for the reasons set out above.

Local Plan Policy 28 sets out criteria for new developments which should have regard to character and design, including (amongst other things) being of a suitable scale, massing and height to the site and maintains the setting and visual amenity of the Green Belt. I find that the proposals conflict with Policy 28 and the provisions of the Framework which seeks to achieve well-designed places.

The proposal constitutes inappropriate development in the Green Belt. I have given the harm associated with this substantial weight. There would also be additional harm through the effect of the development on the openness of the Green Belt. I have given only limited weight to the other considerations cited in support of the development. Taken together, these would not clearly outweigh the harm to the Green Belt identified above.

I find that the other considerations in this case do not clearly outweigh the harm that I have identified. Consequently, the very special circumstances necessary to justify the development do not exist.

The development would therefore be in conflict with Local Plan Policies 24 and 28 and the provisions of the Framework. For this reason and as described above, I conclude that the appeal should be dismissed.