Appeal 3356522

The appeal is allowed, and planning permission is granted for first-floor side/rear extensions at [site address] in accordance with the terms of the application, 24/01034/HOU, 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: 24089 - PL-01, 24089 PL-02, 24089 -PL-03, 24089 - PL-04, 24089 -PL-05, and 24089 - PL-06.

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

Since the appeal was submitted a revised version of the National Planning Policy Framework (the Framework) was published in December 2024. There have been changes to the national Green Belt policy; however, the approach to extensions, as set out in paragraph 154 (c), and the green belt purposes remain the same, and therefore, further comments have not been sought.

The main issues are: - i) whether or not the proposal would be inappropriate development in the Green Belt for the purposes of the development plan and the Framework; and i) the effect of the development on the character and appearance of the area.

The Framework establishes that development within the Green Belt should be regarded as inappropriate unless one of the specified exceptions applies. Exception (c), as set out in paragraph 154, allows for the extension and alteration of a building, provided that it does not result in disproportionate additions over and above the size of the original building.

Saved policy GB1 of the Spelthorne Borough Local Plan 2001 (Local Plan), which refers to ‘limited extensions’, predates the Framework and references the previous national guidance – PPG2. Policy EN2 of the [name] and Policies Development Plan Document (February 2009) ([name]) indicates that extensions should not significantly change the scale of the original building. Notwithstanding the slightly different wording, none of these provides any definition or thresholds for what constitutes an appropriate scale of extension other than confirming that the comparison is to the original building.

The Council advise that as a result of the proposal, together with the existing extensions, there would be a total increase in the footprint of 148% and 95% internal floor area. The calculations are not provided. The proposal would add a first-floor extension above the existing single-storey element to the side of the property and, therefore, would not add to the footprint. This existing side element was not part of the original building but replaced the garage and store with the planning permission (granted in 2020) referring to the demolition of those structures. The property also has a single-storey extension to the rear. From the information before me, the plans and figures provided by the appellant provide a more accurate indication of the changes and calculate an increased footprint of 39% and 38.6% in floor space compared to the original building.

In addition to these calculations, the proposal would have a three-dimensional impact on the scale and volume of the property. It would not increase the coverage of the plot in terms of built form but would add massing to the first floor along the flank elevation with a small projection to the rear. The extension is however, designed as a subservient addition, inset from the front elevation, set down from the main ridgeline and less than half the width of the front elevation.

Therefore overall, I do not find the proposed extension, in combination with the previous alterations, would result in disproportionate additions over and above the size of the original building. It is therefore concluded that the proposed development would not constitute inappropriate development within the Green Belt as defined by the Framework or conflict with the development plan policies GB1 and EN2.

[address] comprises semi-detached properties of the same form. There is regular spacing between the pairs, although the enclave of properties does not have an overly spacious character, having the appearance of a residential estate. No.54 is located at the southern edge with an area of open space to the side, to the other side of which is residential development extending along [address] which is located outside the Green Belt.

Due to the layout and the relationship between the properties opportunities for side extensions are limited; however, the end property directly opposite, No.41, has a very similar extension to that proposed. The Council explain that it was built several years ago and was not assessed against the Green Belt. However, there is no indication that the Green Belt boundary has changed, and the same Local Plan and [name] policies were in place at the time. That extension has integrated into the street scene, and whilst it is slightly offset from the boundary, it is adjacent to the main access route of [address].

In contrast, the access to the side of the appeal property does not lead anywhere, terminating at the rear of the property, and together with the adjacent open space, there is an openness to the side of the appeal property. The extension does not follow the guidance in the Council’s Supplementary Planning Document 'Design of [name] and New Residential Development' (SPD), which advises that two-storey side extensions should be set in a minimum of 1 metre from the closest boundary. However, located at the end of the row, the proposal would not result in terracing or a loss of a visual gap, which the guidance is seeking to avoid. The single-storey element already forms part of the side boundary, and whilst infilling the space above, I do not find that this would be overly imposing or out of keeping with the prevailing form of development.

The design of the extension reflects the existing property and would be constructed in materials to match. Overall, I do not find that the scale or the appearance of the resultant property would be harmful to the character of the area.

Thus, the development would accord with policies EN1 and EN2 of the [name] and the Council’s SPD guidance, taken as a whole, which together seek a high standard of design, for extensions not to significantly change the scale of the property or detract from the character of the area.

The Council also make reference to an outbuilding. The planning history, as set out in the Council’s officer report, includes a lawful development certificate for an outbuilding. Both parties confirm that this has not been implemented, and it was granted more than 3 years ago; I have, therefore, not given it any weight or included it in the calculations. There are domestic structures to the rear of the garden, forming a shed, canopy and trampoline but there is no indication that permitted development rights have been withdrawn.

I have found that the proposal would not be inappropriate development in the Green Belt, and the scale and form of the development would be compatible with the property and the surrounding area. I therefore conclude that the appeal should be allowed. Standard conditions relating to the commencement of development and specifying the relevant plans are necessary to provide certainty. I have also in the interest of the appearance of the building, imposed a condition requiring the materials to match.

As this is a first-floor extension the conditions suggested by the Council in relation to ground levels and the removal of spoil to prevent increased flood risk are unnecessary.