Appeal 3299541

The appeal is allowed and planning permission is granted for alterations to existing main dwelling including changes to roof profile, new dormer windows, new porches and window alterations at [site address] , Rickmansworth [postcode] in accordance with the terms of the application, Ref 22/0069/FUL, dated 17 January 2022, 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: SO-896-10 [name]; SO-896-11 [name]; SO-896-12 [name]; SO-896-13 [name]; SO-896-14 [name].

The main issue in this appeal is whether the proposal would be inappropriate development in the Green Belt having regard to the Framework and relevant development plan policies.

The appeal property is situated within a cluster of buildings and structures, which are generally sited close together and relate to the equestrian function of the site. At the front of the appeal property is a courtyard surrounded by a large stable block and a two-storey building providing living accommodation for staff. Adjacent to the appeal property is a group of large stables and barns. Notably, a large barn near the appeal property’s end elevation is substantially taller and greater in scale and bulk than the appeal property. Within the context of the numerous large buildings within the wider equestrian centre site, the appeal property does not appear especially prominent.

The appeal property is an existing dwelling within the site of an equestrian centre and located within the Green Belt. Paragraph 149 of the National Planning Policy Framework (the Framework) indicates that the extension or alteration of a building is not inappropriate within the Green Belt provided that it does not result in disproportionate additions over and above the size of the original building.

The Council’s Extensions to Dwellings in the Green Belt Supplementary Planning Guidance 2003 (SPG) provides guidance for assessing whether a proposal for the extension or alteration of a dwelling would be ‘disproportionate’. The assessment requires two tests to be satisfied; whether the proposal would exceed a 40 percent increase in floorspace and whether the proposal would harm the Green Belt’s openness.

Through the addition of porches and through utilising existing void areas within the roof space, the proposal would increase the floor area of the existing building. The cumulative increase in floorspace would be around 11%, thereby falling significantly below the SPG’s floorspace threshold of 40%. The proposal would not therefore be disproportionate by virtue of its floorspace increase.

The SPG requires that extensions at first floor level do not significantly extend the width of the original building or in any other way make the building more prominent. The SPG indicates that increases in ridge height or apparent bulk of roof by a full storey will normally be considered to have an adverse effect on the openness of the Green Belt but that is not the case here.

This is a single storey dwelling constructed from brick with a tile roof. The proposal would increase the ridge height by around 0.25m and the eaves height by around 0.7m. Whilst the proposal would alter the height and pitch of the roof, the scale of the increase would be very modest and would alter the height or bulk such that it would be equivalent to a full storey. The proposed alterations at first floor level would not extend the width of the original building, nor add apparent bulk to the roof.

Since the proposed alterations to the roof, dormers, and porches each satisfy the SPD’s criteria, I am satisfied the cumulative effects of the proposal would represent an overall increase in the volume of the appeal property of around 11.6% which represents only a modest increase in the scale of the appeal property. On this basis I conclude that the proposal would not represent inappropriate development in the Green Belt as defined in paragraph 149c).

The proposal would include the addition of four, glazed dormers on the front roof plane set down from the ridge and above the eaves. These would appear subordinate to the roof and therefore accord with the SPD which indicates that the addition of proportionate dormer windows will not normally adversely affect openness.

The SPG indicates that single storey extensions would not normally impact on the openness of the Green Belt and the Council accepts the proposed porches would not appear disproportionate in the context of the proposed development, and in this regard, there would also be no conflict with the SPG. However, the Council suggests the proposed central porch, which would breach the eaves height, would appear disproportionate relative to the existing building and therefore cause harm to arise from the various elements of the proposal applied in combination.

Since the proposed alterations to the roof, dormers, and porches each accord with the SPD’s criteria, I am satisfied the cumulative effects of the proposal would not harm openness. Whilst the appeal property is of single storey height, it is a relatively long building with a wide front and rear elevations. The bulk and massing of the proposal, including the addition of the proposed central porch, would not appear disproportionate to the existing building. The spatial impacts of the proposal, taken as a whole, would not therefore adversely affect the openness of the Green Belt.

The equestrian centre site is situated within an open landscape setting consisting of training areas, paddocks and fields. The site is set back a considerable distance from the public highway, connected by a long private access road. Hedgerows and tree belts along the private access road and enclosing the appeal property’s rear garden provide screening from the direction of the public highway and generally obscure views of the appeal property within the landscape.

From the private access road, the roof of the appeal property is partly visible over the height of the rear hedge. However, due to the extensive screening and the presence of surrounding large buildings, the proposed alterations to the roof would not increase the prominence of the appeal property within the landscape and would not be readily apparent from the open landscape to the south-east of the site. The visual impacts of the proposal on the openness of the Green Belt would therefore be neutral.

As set out above, the proposal would not lead to an unacceptable increase in floorspace, and its spatial and visual impacts would not harm the openness of the Green Belt. The proposal would satisfy the guidance contained in the SPD and would not therefore result in disproportionate additions over and above the size of the original building. Consequently, the proposal would not form inappropriate development within the Green Belt. The proposal would therefore comply with Policy CP11 of the [name] 2011 which sets out a general presumption against inappropriate development in the Green Belt, and Policy DM2 of Development Management Policies Local Development Document 2013 which resists disproportionate size extensions to buildings in the Green Belt. In addition, the proposal would not conflict with the five purposes of the Green Belt set out at Paragraph 138 of the Framework.

In addition to the standard time limit of the planning permission granted, in the interests of certainty I have attached a condition specifying adherence to the approved plans.

For the reasons given above, the appeal is allowed and planning permission granted, subject to the conditions set out in the formal decision above.