Appeal 3314148

The appeal is dismissed.

I consider the main issue to be the effect of the proposed development on the architectural integrity of the host property and thereby whether the proposal would serve to preserve or enhance the character or appearance of the Horsham Conservation Area.

The appeal property, [site address] is a detached two-storey dwelling. It is one of a small enclave of relatively contemporary dwellings located in the Horsham Conservation Area.

It is of a simple gable roof design with a projecting flat roof garage incorporating the main entrance door. The fenestration pattern is equally simple and regular, typical of dwellings of this age. However, it has an unusual, but attractive, window at first floor level to the street façade lighting the staircase and landing area.

The appellant proposes the conversion of the loft to habitable accommodation. The development would include the formation of one dormer to the front roof slope along with two roof windows. In addition, two dormers to the rear roof slope are proposed.

The Council found the front roof lights modest and therefore acceptable. From what I have seen and read I would not disagree with this view.

In respect of the front dormer, I am sympathetic to the idea of reinforcing the original designers’ concept of making the staircase and it’s lighting a feature of the design of the principal elevation. However, due to the design, height, relationship to the ridge line, proposed detailing and materials indicated the front dormer would appear as a bulky and unattractive feature when viewed from the street. As designed therefore it would appear as an incongruous and unattractive feature that would serve to denude the architectural integrity of the existing dwelling.

In principle, given the design of the host property, I consider that simple flat roofed dormers would be an appropriate design solution for the rear roof slope here. However, due to the positioning of the dormers, off set from the windows below, there overall size and the proportions of the windows themselves in relation to the existing fenestration pattern the two dormers would have an adverse impact on the character and appearance of the host dwelling. Furthermore, by positioning them so high in the roof they would have an uncomfortable relationship with roof slope itself.

In my judgement for all these reasons the proposed development, by virtue of the design, scale, massing and proportions of the front and rear dormers, would represent unduly dominant and incongruous additions which would cause significant harm to the architectural integrity and character of the existing dwelling. The development as designed would therefore fail to preserve or enhance the character or appearance of the Horsham Conservation Area.

The National Planning Policy Framework (the Framework) requires great weight to be given to the conservation of designated heritage assets, which include conservation areas. It draws a distinction between substantial harm and less than substantial harm to such an asset. For the latter, which applies here, the test is that the harm should be weighed against public benefits, including securing the optimum viable use.

The proposed development would provide some limited economic benefit. However, given the harm that has been identified I conclude that the public benefits would not outweigh this harm, or the conflict that it would have with the objectives of Section 72(1) of the Planning (Listed Buildings and Conservation Areas) Act 1990, the Framework and Policies 32, 33 and 34 of the Horsham District Planning Framework (November 2015) and Policy HB3 and Policy HB4 of the Horsham Blueprint Business Neighbourhood Plan 2019-2036 (August 2022) as they relate to, along with other things, the quality of development and the preservation or enhancement of the character or appearance of conservation areas.

For the reasons given above and having regard to all other matters raised, I conclude that the appeal should be dismissed.