Appeal 3338502

The appeal is allowed and planning permission is granted for a replacement rear extension and internal refurbishments at [site address] in accordance with the terms of the application, Ref 23/03151/HOU, subject to the conditions set out in the attached Schedule of Conditions.

The main issue is the effect of the proposed development on the character and appearance of the existing building and surrounding area, including on the [address] Conservation Area.

The appeal concerns a three storey (plus lower ground floor) detached dwelling located within the [address] Conservation Area (CA). Section 72(1) of the Planning (Listed Buildings and Conservation Area) Act 1990 requires that special attention be paid to the desirability of preserving or enhancing the character or appearance of that area. Similar advice is contained within the National Planning Policy Framework (the Framework) and in Policy HC1 of the London Plan 2021 (LP) and Policies CS8 and DM12 of the [site address] [name] 2012 (CS). The Council’s Residential Design Guide Supplementary Planning Document (July 2013) (SPD) provides further advice in interpreting the design and heritage aims of the CS.

The special character of the CA derives from the individually designed detached and semi-detached houses dating from the 1850s set in a mature landscape on the edge of Richmond Park. The appeal site is located in part of the CA that is more mixed in character and appearance, comprising of large houses and modern blocks of flats. The row of houses to the north of the appeal site are of a similar appearance to the appeal property, whilst [address] to the south is a more modern flatted development.

The appeal property has subsequently been extended particularly to the rear but it does, particularly in terms of its front elevation, retain much of its original character and contributes positively to the significance of the CA.

The proposed development seeks to replace the existing glazed lower ground and ground floor rear extension with a new extension of a similar width and depth. A small section of the extension with a width of around 4m would extend a further 2.2metres at lower ground floor level whilst the remainder of the extension at lower ground and ground level would extend 0.55m deeper to the rear. A small extension is also proposed at first floor level, with the angled side wall of the existing bathroom proposed to be squared off.

The existing extension is a large, glazed structure with a steep sloping roof which, due to its width, depth, height and expanse of glazing dominates the rear elevation of the host dwelling. In my view, the existing extension does not positively contribute to the character and appearance of the existing dwelling or the surrounding area.

The proposed extension would be of a stepped design, reflecting the gentle sloping topography of the site. The extension would have a contemporary appearance, incorporating sections of flat roof with a large expanse of glazing on the rear elevation.

The extension, although stepped, would be lower in height overall than the existing structure to be replaced by about 0.7m. Only two small sections of the stepped extension would be higher than the existing sloped roof. Given that the proposed extension would have similar height and depth to the existing extension overall, I conclude that the extension would be acceptable in terms of its overall scale and bulk.

In terms of the design and form of the proposed extension, there are other flat roof extensions in the local area. In my opinion, the flat roof design would also reflect the design and appearance of the existing flat roofed outrigger such that the extension would not appear out of keeping with the host dwelling or the surrounding area.

The stepped profile of the south elevation of the proposed extension would be visible from [address] through the gap between the appeal site and the adjacent flatted development, [address]. It would also be visible from the access that runs to the side of the adjacent flats, leading to the parking courtyard to the rear. However, this is currently the case with the high, sloping flank wall of the existing extension. The external flank wall would be constructed in brick to match the appearance of the host dwelling and given its lower height and stepped nature, the extension would not be appreciably more visible or prominent in the street scene. I consider that the limited views of the extension that would be obtainable would not be harmful to the character or appearance of the surrounding area.

As with the existing extension, the rear of the extension would incorporate an extensive amount of glazing, timber and aluminium frames, complementing the contemporary design. The replacement of the existing window on the outrigger with a new sash window to match existing is also a positively aspect of the scheme. The proposed rendering of the external outrigger would match the appearance of the internal outrigger and is in my view is logical. I also observed that rendering is also a common feature of other buildings in the conservation area and given the subservience of the outrigger to the original main dwelling, I find the proposed rendered exterior to be acceptable.

A limited amount of a stone façade is also proposed to complement the render, with the intention of maintaining subservience and differentiating the modern extension from the original dwelling. [name] have only limited details of the proposed stone façade and the other materials such as the timber and aluminium, I can see no reason in principle to find the design approach or materials unacceptable. Precise details of materials could be controlled by condition in the event that the appeal is allowed.

The proposed extension would not harm views of the original fabric of the dwelling as the original rear walls have been almost completely removed at lower ground and ground level in association with the previous glazed extension. The proposed extension would be no more harmful in terms of its effect on the integrity of the existing building in this respect.

Therefore, having regard to the above considerations and given the modern glazed extension that the proposed development would replace, I find that the proposal would have a neutral effect on the character and appearance of the CA.

The statutory duty in Section 72(1) of the Planning (Listed Buildings and Conservation Areas) Act 1990 (the Act) is of considerable importance and weight. Paragraph 203 of the Framework states, amongst other things, that the desirability of new development making a positive contribution to local character and distinctiveness should be taken into account in determining applications. Paragraph 205 of the Framework also advises that when considering the impact of development on the significance of designated heritage assets, great weight should be given to their conservation. However, for the reasons outlined above, I am satisfied that the proposal would preserve the character and appearance of the CA.

I therefore conclude that the proposal would not have a harmful effect on the character and appearance of the existing building and surrounding area, including on the CA. The proposal would comply with Policies DC3 and HC1 of the LP and Policies CS8, DM10 and DM12 of the CS. Together these policies seek to protect the district’s heritage assets and require development proposals to enhance local context and to ensure that the character and local distinctiveness of a street or area is respected, maintained or enhanced. The proposal would also comply with the main design and heritage aims of the Council’s SPD.

The Council also refer to Policy DM11 in their refusal reason. However, as this policy does not to apply to minor development such as householder extensions, I consider it to be of little relevance to the appeal proposal.

The Council has suggested a list of planning conditions in the event that this appeal was to be allowed. I have incorporated most of the suggested conditions, with some adjustments for clarity.

In addition to the standard implementation condition, the approved plans condition is imposed for certainty. Conditions relating to the submission of detailed drawings and requiring the approval of materials are necessary to protect the character and appearance of the dwelling and the local area. A condition to ensure compliance with the submitted [name] is necessary in order safeguard trees worthy of retention and to protect the character and appearance of the area.

I have imposed conditions to control the insertion of additional windows and other openings and to control the use of the flat roof areas of the extension in order to protect the living conditions of surrounding occupants.

Finally, as recommended by the Council, I have imposed a condition relating to [name] to ensure the future safety of all building users, in accordance with Policy D12 of the LP.

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

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: 654 P01; 654 P12 [name]; 654 P13 [name]; 654 P15 [name]; 654 P16 [name]; and 654 P17 [name].

No development shall take place above ground level until details / samples of the materials to be used in the construction of the external surfaces of the extension hereby permitted have been submitted to and approved in writing by the Local Planning Authority. The development shall be carried out in accordance with the approved details / samples.

Prior to the commencement of any development above ground level, detailed drawings at a scale of 1:20 of the following features shall be submitted to and approved in writing by the local planning authority: - New stone façade - Timber fins and cladding; - Fixed glazing together with the type of glazing and frames to be installed. The development shall then be carried out in accordance with the approved details.

Notwithstanding the provisions of the Town and Country Planning (General Permitted Development) (England) Order 2015 (as amended) (or any Order revoking and re-enacting that Order with or without modification), no windows shall be inserted nor any other openings formed (other than those expressly authorised by this permission) at ground floor level or above in the [name] ([name] 654 P15 [name]) and [name] ([name] 654 P16 [name]) of the proposed single storey rear and first floor rear extensions unless otherwise agreed in writing by the local planning authority.

The flat roof areas of the development to which this permission relates shall not be used as a roof garden, balcony, eating area or other similar amenity area, and shall not be accessed except for the purpose of maintenance or in the case of emergency.

The development to which this permission relates shall be carried out in accordance with submitted [name] dated 16.10.23. The approved measures shall be implemented prior to commencement of any work on site and maintained to the reasonable satisfaction of the Local Planning Authority until the completion of the development.

Prior to any above-ground works of the development to which this permission relates, a [name] shall be submitted to and approved in writing by the local planning authority. The Fire Safety Strategy shall demonstrate how the development will achieve the highest standards of fire safety and shall include the following details:

Suitable positioned outside space for the fire appliances /an evacuation assembly point;

Appropriate fire alarm systems;

Passive and active fire safety measures;

Appropriate construction details to minimise the risk of the fire spread;

Provision of suitable access and convenient means of escape / an evacuation strategy;

Provision of suitable access and equipment for firefighting which is appropriate for the size and use of the development. The Fire Safety Strategy shall include a statement of competence. The development shall be carried out in accordance with the approved Strategy and thereafter maintained. The required [name] shall reference the London Plan Guidance Fire Safety (February 2022) where applicable and a [name] (RES) shall be submitted in relation to those fire safety requirements which the applicant does not consider to be relevant.