Appeal 3363308

The appeal is allowed, and planning permission is granted for the erection of a second floor roof extension with hip to gable detail, including extension over a two storey side addition on the west flank of the property. Roof lights on front roof slope at [site address] , Merton, Wimbledon, [postcode] , in accordance with the terms of the application 25/P0248, 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 numbers: CA 01; Block Plan; Site Location Plan; [name].

The development hereby permitted shall be carried out in accordance with the approved Flood Risk Assessment (FRA) and the following mitigation measures detailed within the FRA retained in perpetuity: • No basement accommodation in the property. • The finish floor level of the new extension will be at the same level as the existing ground floor level of the house, 220mm above ground level. • Door threshold will be set above external garden level by 230mm. • All low level joints and cracks will be sealed with resilient mastic. • The floor construction will be flood resilient - solid screed on insulation and concrete slab. • Weeping holes in external brickwork.

The site visit was undertaken by a representative of the Inspector whose recommendation is set out below and to which the Inspector has had regard before deciding the appeal.

The appellant submitted a [name] with the appeal to respond to reason for refusal 2. The Council were given the opportunity to provide comments and set out that the proposal accorded with Policy D12 of the London Plan 2021. I agree and have proceeded with the appeal on this basis.

The planning history of the site sets out that planning permission exists for a hipped roof extension and dormer on the original roof. The main difference with this appeal is that it seeks to change the roof to a gable with a rear dormer.

The effect of the proposal on the character and appearance of the host dwelling and the surrounding area.

Located in a prominent position adjacent to a communal amenity space and a public footpath, [site address] is an end of terrace two storey dwelling. It has a cat slide gable roof to the front elevation, which is repeated at the end of the terrace row. It is a feature that contributes positively to the character and appearance of the area and is used to book end terraces or to pair semi-detached properties.

The remaining main roof of No 29 is hipped. However, the opposite end of the terrace has a hip to gable roof conversion which unbalances the pattern of the terrace. Additionally, in the wider area there are numerous hip to gable roof conversions. No 29 has a two storey flat roof side extension and a full width single storey rear extension. Those extensions have different heights and roof forms, appear disjointed and detract from the appearance of No 29 and its visual contribution to the terrace and surrounding area.

The proposal is for a hip to gable roof extension and rear dormer. The hip to gable conversion and roof extension would extend over the existing 2 storey side extension. Despite the increased width and mass, the design would create a unified appearance in terms of one roof, a singular ridge line and a cohesive appearance. The roof design would match that of the opposing end of the terrace, unifying the terrace in terms of gable ends. As a result, the proposal would balance both the dwelling and the terrace as a whole, improving the appearance of the front and side elevations, and the visual cohesion of the terrace. The setback of the side extension would signal subservience of the extension despite the roof not being set back at this location. The cat slide gable roof would remain, continuing to contribute positively to the front elevation.

The proposed rear dormer would extend across the existing roof slope and roof extension, albeit set back from the gable end and the eaves of the roof. The fenestration would be aligned with the fenestration below. Rear dormers exist in both the terrace and the wider area, and these mostly extend across the width of the roof. Whilst the dormer would increase the mass of the rear elevation, when viewed as a whole it would be a well-balanced rear roof extension. Other rear roof extensions in the area cover the full width of their roofs and as such full width rear dormers are characteristic of the area where they exist.

Overall, there would be an improvement in the visual cohesion of the dwelling and the terrace. As a result, the proposal would respond positively to the context and character of this site in this prominent location and respect the prevailing positive characteristics of the area. Accordingly, the proposal would comply with Policies D3 and D4 of the London Plan (2021), Policies D12.1, D12.3 and D12.4 of the Merton Local Plan (2024) insofar as they seek well designed proposals that respect the appearance, scale, bulk, form, proportions, materials and character of the original build and their surroundings.

In the interest of certainty and precision, it is necessary to define the plans with which the appeal scheme should accord. The Council suggested a condition requiring that the materials to be used in the construction of the external surfaces match those of the existing building. This would be unnecessary given the detail provided on the approved plans.

A condition requiring implementation of the flood mitigation measures identified in the Flood Risk Assessment are necessary given the site’s location within an area identified as increased potential for groundwater flooding.

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

I have considered all the submitted evidence and my representative’s report and on that basis the appeal is allowed.