Appeal 3350131

The appeal is allowed and planning permission is granted for the demolition of a single storey utility room and addition of two dormer windows together with internal alterations and changes to windows/doors at [site address] , [site address] , [postcode] , in accordance with the terms of the application, Ref 24/06133/FUL, and the plans submitted with it, 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 no. 6170-04A.

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

An application for costs has been made by the appellant against the Council. This is the subject of a separate decision.

The main issue is whether the proposal, in association with previous extensions, would result in a disproportionate addition to the original building and therefore constitute ‘inappropriate development’ in the Green Belt.

The appeal site comprises a detached property set in a ribbon of similar properties in a rural area which also forms part of the Green Belt. At the moment the main part of the property has two levels of accommodation with the upper floor set in the roofspace and lit by dormer windows. There are three individual small dormers on the front roof slope and a box dormer on the rear one. At the side of the property there is an attached garage and utility room with a bedroom above. The bedroom is lit by rooflights and the proposal is to replace these with two small dormer windows, one on either roof slope.

The National Planning Policy Framework (the Framework) indicates in paragraph 153 that ‘inappropriate development’ is harmful to the Green Belt and should not be approved except in very special circumstances. Paragraph 154 sets out that development is inappropriate unless one of the stated exceptions applies and the one relevant to this case is (c) regarding the extension or alteration of a building provided that it does not result in an disproportionate addition over and above the size of the original dwelling. The term ‘original dwelling’ is defined in the Glossary to the Framework as the building as it existed on 1 July 1948, or if constructed afterwards, as it was built originally.

Wycombe District Local Plan (WDLP) Policy DM43 relates to the replacement or extension of dwellings in the Green Belt and sets out detailed criteria to govern the size of extension that may be added to an existing dwelling, including a restriction on the total volume of additions which vary depending on the size of the original dwelling.

The Council’s evidence suggests that the existing bungalow was permitted in 1958 and with extensions permitted in the period 1958 to 1979 but plans for a ‘hip to gable’ roof extension refused in 2019. The Council says that the original dwelling had a gross volume of 424.44 cubic metres and therefore part (e) of Policy DM43 applies which limits the total increase in volume that can be added to 50% of the original. The Council calculates that the cumulative additional volume added to the property by now equals a 102% increase and the volume increase in the proposed two dormer windows would increase this to 103%.

There is a dispute between the parties over the status of a small utility room at the rear of the property shown on the submitted plan and mentioned in the description as to be demolished. The volume of this structure is apparently greater than the volume of the dormers proposed to be added. The dispute centres on when the utility room was demolished or if it can be included in the current calculation of respective volumes. However, the appellant agrees that the utility room was demolished in 2016 and I find that it should not have a bearing on the current calculation notwithstanding the fact that such work was included in the description of the current proposal.

In any event, the cumulative increase in volume of the property already greatly exceeds the limitation in part (e) whatever view is taken on the demolition of the utility room. As the proposal stands it conflicts with part (e) of Policy DM43 in terms of the cumulative scale of additions to a property.

However, as well as this mathematical formula, part (c) of the Policy relates to properties which lie within a ribbon of development that presents a substantially built-up frontage, and where the resultant dwelling would not exceed the average volume of its two directly adjacent neighbours.

In this case I am satisfied that [address] lies in a ribbon of development that is a substantially built up frontage. Although the Council has considered this criteria there appears to be a lack of information on the neighbouring houses ([address] and Wentworth) to calculate volume. The Council report says that a visual inspection has been made but there does not appear to be a conclusion on this aspect.

At my site visit I considered the present scale of the immediately neighbouring properties viewed from the public realm. It appeared to me that Wentworth was smaller although of a similar form with a high-pitched roof but no dormer windows on the front elevation. On the other side, [address] was larger with a similar form of footprint with more volume on the upper floor with a larger roof based on gable ends with half-hips of the main roof and extension together with four small dormer windows and a larger projecting dormer. Taking the two properties together at the moment, the proposed additional dormers on [address] would not result in an enlarged property which exceeds the average volume of the two directly adjacent neighbouring ones.

On this basis I find that the proposed dormers reasonably comply with part (c) of Policy DM43 and therefore do not result in disproportionate additions. As such the proposal meets the terms of paragraph 154(c) of the Framework and does not constitute ‘inappropriate development’.

The accord with the development plan and relevant national policy is not outweighed by any other factor and therefore the appeal should be allowed.

The Council advises that standard conditions be imposed to regulate the commencement of development and to accord with the approved plans; and that the external materials of the dormer shall match the existing ones. These are reasonable and necessary to maintain the appearance of the dwelling and the character of the area and I will impose them.

For the reasons given above the appeal should be allowed.