Appeal 3345046

The appeal is allowed and planning permission is granted for replacement dormer extension to front of dwelling at [site address] in accordance with the terms of the application, Ref 2024/00089/FULH, subject to the following conditions:

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

The development hereby permitted shall be carried out in accordance with drawing nos: 23-JD-11TDL-CD-2000 - location plan 23-JD-11TDL-SD-307 - proposed site plan 23-JD-11TDL-SD-509 - proposed first floor plan 23-JD-11TDL-SD-510 - proposed roof plan 23-JD-11TDL-SD-511 - proposed elevations 23-JD-11TDL-SD-512 - proposed sections

The external materials of the dormer extension hereby permitted shall match those used in the existing dwelling.

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

The appeal property is a modern semi-detached house, located at the end of a cul-de-sac formed of similar properties. The site is within the small settlement of Broomedge, and is in the Green Belt. https://www.gov.uk/planning-inspectorate - null APP/M0655/D/24/3345046

In order to prevent urban sprawl and keep land permanently open, paragraph 154 of the National Planning Policy Framework (the Framework) says that the construction of new buildings is inappropriate in the Green Belt, unless it meets one of the exceptions listed. These include 154c), which allows for 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.

No further guidance as to what constitutes a ‘disproportionate addition’ is provided in the Framework or in Policy GB1 of the Warrington Local Plan

However, the House Extensions Supplementary Planning Document 2021 (SPD) does contain further information on this matter. This states that any extensions and additions that result in an increase in size of over 33% of the original building will be considered to be disproportionate, and therefore unacceptable. The SPD notes that an assessment of proportionate increase should be based predominately on calculations of volume and floorspace, and that footprint and height will be considered in terms of design and character.

The appeal property already has a single storey extension, and according to the Council’s calculations, this has resulted in a 57% increase in the volume of the original house. This is disputed by the appellant, who suggests a lower figure of 48% should be used. I do not have sufficient information to make my own assessment, but even using the appellant’s lower figure, the SPD threshold of 33% has been exceeded quite significantly.

To provide additional bedroom space, the appeal now seeks permission to replace the existing front dormer with a slightly larger one. The parties agree that the proposed extension would provide an additional 4.4 cubic metres compared with the existing situation, and that this would equate to a further 1% increase in volume.

The proposed addition would be very modest, but as the volume of the property has already been extended by more than 33%, no further extensions would be acceptable under the terms of the SPD. That said, the SPD is guidance rather than policy, and whilst it is a material consideration in this appeal, there are other factors to take into account.

The most recent decision, in 2017, would have predated the current local plan and SPD, but would have been subject to the same policy tests in the Framework. I can only assume that, in granting planning permission, the Council took the view in 2017 that the proposed addition to the existing single storey extension would not result in a disproportionate increase over and above the original dwelling.

The dormer replacement now proposed would further increase the volume and internal floorspace of the property, but only by a very small amount. It would sit within the existing roofplane, so would not increase the height of either the main roof or the existing front gable. There would be no change to the footprint of the house, and very little appreciable difference to the overall size of the property.

The proposed addition would result in a very small volumetric increase over and above that of the existing extension, which was considered acceptable. Even though it would not comply with the detailed guidance in the SPD, I am satisfied that the minor works now proposed would not result in a https://www.gov.uk/planning-inspectorate - null APP/M0655/D/24/3345046 disproportionate cumulative addition over and above the size of the original building. Therefore, in terms of Framework paragraph 154, the appeal proposal would not be inappropriate development.

Owing to its small scale and position on the existing building, the proposed dormer would have no impact on Green Belt openness, either visually or spatially.

In light of the above factors, I conclude that the proposal would not be inappropriate development in the Green Belt. It would be consistent with Local Plan Policy GB1, which gives support to proposals which comply with national policy contained in the Framework.

Standard conditions relating to implementation timescales and plans are needed in the interests of certainty. To ensure a satisfactory appearance, a condition requiring matching materials is also required.

For the reasons set out, the proposed replacement dormer would not be inappropriate development in the Green Belt, and I have identified no other harms that would be caused. The appeal is therefore allowed, subject to the conditions above.