Appeal 6005288

The appeal is allowed and planning permission is granted for a first floor rear extension and a single storey rear extension at [site address] , [site address] , Hertfordshire [postcode] in accordance with the terms of the application, Ref 3/25/1692/HH, 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: ELA/1A, ELA/2A, ELA/3A, ELA/4A, ELA/5A, ELA/6A, ELA/13A, ELA/14A and ELA/18A.

The materials to be used in the construction of the external surfaces of the extension hereby permitted shall match those used in the existing building, with the exception of external door materials as stated on the application form.

The main issue is whether the proposal would be inappropriate development in the Green Belt.

[address] is a street of mainly large, detached houses of varied architectural character, sitting back from the street on generously sized plots within this loosely built-up village. No 14 is typical in all these respects. It has an asymmetrical 2 storey rear wing, including a cat-slide roof that drops down to a flat roofed single storey section. The proposal would add to the first floor at the back, re-forming the rear wing into a full width 2 storey gabled section with the roof ridge running parallel to the main roof. A further single storey rear extension would be added behind the 2 storey section.

[site address] is washed over by the Green Belt. Paragraph 153 of the National Planning Policy Framework (the Framework) advises that inappropriate development is by definition harmful to the Green Belt and should not be approved except in very special circumstances. Paragraph 154 explains that development in the Green Belt is inappropriate unless one of the listed exceptions applies. These exceptions include: (c) 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. East Herts District Plan (DP) policy GBR1 states that planning applications for development in the Green Belt will be considered in line with the provisions of the Framework.

Neither the Framework nor DP policy GBR1 defines the term disproportionate additions, leaving this to a case by case assessment. The Framework refers to the size of the resulting building in relation to the original building. The cumulative physical size of additions in relation to the original structure (in this case as existing in 1948) is therefore the key consideration, though visual impact may also play a part in the assessment.

Based on a historic OS plan, the Council estimates that the original house had a footprint of about 72 sqm and a floorspace of about 143 sqm. Of these 2 measurements I take floorspace to be the more accurate representation of size, as footprint tends to overemphasise the scale of single storey sections. The Council measures the existing building to have a floorspace of about 205 sqm, nearly a 44% increase in comparison to the original building. It advises that this proposal would bring the cumulative increase in floorspace to about 65%.

The appellant does not dispute these figures, which indicate a cumulative increase significant enough to potentially be considered disproportionate. On the other hand, however, the proposal has been well-designed to minimise its bulk, massing and visual impact. The proposed first floor extension would consolidate the form of the house at the back, dropping down in height and making efficient use of the space without giving the impression of a significantly larger building. The proposed extensions would furthermore be almost entirely screened from public view by the existing building - even though some new views have been opened up by the ongoing construction of a new house on the site next door. The actual visual impact of the proposal would therefore be very limited.

On balance I conclude that the proposal, taken together with existing extensions, would not represent a disproportionate addition to the original building. The proposal is therefore not for inappropriate development in the Green Belt and accords with both the Framework and DP policy GBR1.

Neither the Council nor any third parties have raised any other objections to the proposal. I impose a condition specifying the relevant plans to provide certainty. A condition requiring the use of matching materials is needed to protect the character of the house and the local area.

I find that the proposal accords with the development plan and the Framework. For the reasons set out above, and having regard to all other matters raised, I conclude that the appeal should succeed.