Appeal 3285759

The appeal insofar as it relates to the dormer, hip-to-gable extension, rooflights, and single-storey extension is dismissed.

The appeal insofar as it relates to the garden room is allowed. Planning permission is granted for a garden room at [site address] in accordance with the terms of application Ref 21/03111/FUL, dated 3 August 2021, 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 the following approved plans only insofar as they relate to the garden room: DWG 0434 PL 01 02 (Location Plan), DWG 0434 PL 02 Rev 02 (Site Plan), DWG 0434 PL 03 Rev 02 (Garden Plan), and DWG 0434 PL 12 Rev 02 (Garden room Floor Plan, Roof Plan, and Elevations) all dated July 2021.

No development in respect of the garden room shall take place until details of the external materials to be used have been submitted to and approved in writing by the local planning authority. The development shall thereafter be carried out in accordance with the approved details.

No site clearance, preparatory work or development shall take place until a scheme for the protection of the trees identified in plan 0434 PL 03 Rev 02 shall have been submitted to and approved in writing by the local planning authority. The scheme for the protection of the trees shall be carried out as approved.

The site visit was undertaken by an Appeal Planning Officer whose recommendation is set out below and to which the Inspector has had regard before deciding the appeal.

The main issue is whether the proposal would preserve or enhance the character or appearance of the [address] Conservation Area.

The site is located within the [address] Conservation Area (CA). The CA includes 4 predominantly residential streets and is generally defined by two-storey late Victorian properties with hipped slate roofs and red and yellow stock-brick exteriors. The property is one half of a two-storey semi-detached pair. The other half, [address] (No 10), has a hip-to-gable extension. Aside from this, buildings on the western side of [address] are largely identical in appearance when viewed from the street. At the rear, properties are characterised by three-storey outriggers that mirror the attached dwelling. The properties along [address], including the appeal site, contribute positively to the CA.

Single-storey rear extensions are common, though generally these are infill extensions that do not extend past existing corners, or are extensions placed at the ends of outriggers at ground-floor level. Almost all of these extensions maintain the same width as the original outrigger or building, and are not connected to one another. Although there is a large dormer on the rear of No 10 and a number of dormers on other properties that are small and narrow, I saw that rear dormers are not a characteristic feature of the roofscape on this side of the road.

The proposal would involve a number of roof alterations, namely a hip-to-gable roof extension, a flat-roof rear dormer window, and rooflights on both the front and rear roof slopes. Whilst hipped roofs are the prevailing roof form, the Council have stated that the hip-to-gable extension would mimic the roof at No 10 and create symmetry between the semi-detached pair when viewed from the road, and hence would be acceptable in this instance. In coming to this decision, the Council have also considered the recent appeal decision1 at [address] (No 7). From the evidence before me and what I saw on my visit, I have no reason to disagree.

The Council has no objection to the rooflights provided they are conditioned to be sympathetic in appearance. I saw a number of rooflights on properties along [address]. Considering their small size and unobtrusive design, details of which could be conditioned to ensure they are flush fitting with the roof and low profile, I too find these acceptable.

Although the dormer would be set down from the roof ridge, set in from the sides and eaves, and reduced in size from the previous application, it would still appear larger than most others on the western side of the road. Policy Q11 1 APP/N5660/D/19/3241868 dated 21 January 2020 of the Lambeth Local Plan (the Local Plan) expects dormers on heritage assets to be modest in size and aligned with the openings below. Whilst the dormer would be centred on the pair of windows below, it would not align with them. Furthermore, the front face of the dormer would not contain just the window, as advised by the Building Alterations & Extensions Supplementary Planning Document (September 2015) (SPD). Instead, the sash window would include walls around it to the side, and a deep edge at the top and bottom, making the detailing heavy.

Due to its size, position, design, and fenestration detailing, the dormer would appear incongruous and an unduly dominant addition to the roof of the host property. In turn it would result in harm to the character and appearance of the dwelling and to the CA. Accordingly, it would be contrary to Policy Q11 of the Local Plan as described above. It would also be contrary to Local Plan Policies Q5 and Q22 which together seek to ensure that the design of the development is a contextual response to positive aspects of the locality and historic character, and that development proposals affecting conservation areas respect and reinforce the established positive characteristics of the area. It would also be contrary to the design advice in the SPD described above, and would fail to adhere to the National Planning Policy Framework (the Framework) and its aim to ensure development is well designed and sympathetic to local character.

The Council have indicated that the dormer at No 10 was approved with regard to an older development plan. The appeal has been assessed with regard to the current development plan. Dormers of this size and design are not typical features and it therefore seems to me that a convincing precedent for such development has not been established. Accordingly, the dormer at No 10 would not mitigate the harm that would arise.

[name] 7 is similar in appearance to the appeal property, most properties on the eastern side of [address] are designed differently, and dormers are more common. The appellant has used the design and size of the dormer at No 7 as a reference for the appeal dormer. However, from the description of the development a dormer already existed at No 7 and the proposal was to extend it. Hence, the context for the dormer at No 7 is not directly comparable to the appeal proposal before me, and given the above, it would not justify the harm identified.

Local Plan Policy Q11 expects infill extensions on heritage assets to be set back from the end of the main return. Furthermore, the SPD states that infill extensions can be acceptable, provided they achieve subordination. For heritage assets extensions should stop short of existing corners to better emphasise their subordination.

The extension would infill the gap between the side of the rear return/outrigger and the shared boundary with No 14. The extension would have a greater depth than the outrigger as it would extend some 2 metres beyond the end elevation and corners of the return and also extend beyond the side elevation of the property. In these respects, the extension would fail to achieve an appropriate degree of subservience, and would relate poorly to the rest of the property and would fail to preserve or enhance the character and appearance of the property and the CA.

Accordingly, the infill extension would be contrary to Local Plan Policies Q5, Q11, and Q22 whose aims have already been outlined above. It would also be contrary to the design guidance in the SPD mentioned above.

The single-storey development approved at No 7 is much larger than the proposal, but does not extend past the side elevation of the original building and so retains a degree of subserviency. Full details of the development at No 14 have not been provided. However, works were underway during my site visit, and what I saw suggests the extension would not pass existing corners. Whilst consistency in decision-making is important, all decisions turn on their own particular circumstances based on the facts and evidence before the decision-maker at the time. I must determine the appeal before me on its own merits. Neither of these extensions would justify or mitigate the harm I have identified.

The proposed garden outbuilding would be sited at the bottom of a sizable garden, a substantial distance away from the dwelling. As a result, it would avoid direct interference with the character and appearance of the main dwelling by virtue of the distance between them. Since the previous refusal, the external materials have been revised. Instead of zinc cladding (which the Council still refer to in its officer report), the building would now be clad in brick and lead. The Council’s Conservation Officer is generally supportive although the plans do not show how these materials would be used. Nonetheless, the garden room would be of an appropriate size and scale and would be appropriately distinct from the main dwelling. However, as the plans lack detail of how the brick and lead would be used to face the outbuilding it will be necessary to impose a condition requiring the submission of details of the brick and lead materials. On this basis I am satisfied that the garden room outbuilding would preserve the character and appearance of the CA. Accordingly, it would comply with Policy Q14 that seeks, amongst other things, to ensure domestic curtilage structures do not exceed one storey and are set back at least 1 metre from all site boundaries. It would also accord with Policies Q5 and Q22 of the Local Plan whose aims have already been outlined above.

Section 72(1) of the Planning (Listed Building and Conservation Areas) Act 1990 requires that special attention is paid to the desirability of preserving or enhancing the character or appearance of conservation areas. Paragraph 199 of the Framework states that great weight should be given to the conservation of designated heritage assets. Irrespective of the degree to which the development would be seen from outside the site, harm to the character and appearance of the building would still be caused and result in a failure to preserve or enhance the character or appearance of the CA.

In cases such as this, where the harm to the significance of the heritage asset would be less than substantial, paragraph 202 of the Framework requires that the harm should be weighed against the public benefits. Whilst the proposed single-storey extension and dormer would enlarge the residential accommodation this is a private benefit. No substantive public benefits have been put forward which would outweigh the harm I have identified.

I have considered the conditions put forward by the Council against the advice in the Framework and Planning Practice Guidance. Standard conditions relating to the commencement of the development and compliance with the plans submitted are necessary to provide certainty. As the permission only relates to the garden room, a condition ensuring the external materials match the existing building would not be necessary. However, a condition ensuring the details of the materials to be used in the garden room are submitted to and approved by the Council is necessary to ensure the garden room would have an appropriate appearance in the interest of the character and appearance of the CA. Given the nature of the proposal, additional drawings would not be necessary. The works relating to the construction of the garden room could impact the trees nearby that contribute to visual amenity. A condition to ensure the trees are protected before work begins is therefore necessary.

I have the powers to issue a split decision should I find parts of the appeal scheme to be acceptable and others unacceptable, provided the different elements are clearly severable, both physically and functionally, from each other.

I have found the garden room would not harm the character and appearance of the CA. It would be located at the bottom of the garden and would be clearly physically and functionally severable from the host property. Consequently, it can be granted planning permission.

With regard to the alterations to the roof, the plans show the dormer, hip-to-gable extension and rooflights overlap and are clearly not physically and functionally severable from each other. As a result, the hip-to-gable extension and rooflights, although acceptable, cannot be granted approval as part of a split decision. I have found the single-storey extension would harm the character and appearance of the CA and this would also be refused.

Based on the above, and having regard to all matters raised, I recommend a split decision. That is, to dismiss the appeal in relation to the dormer, hip-to-gable extension, rooflights, and single-storey extension, and allow the appeal in relation to the garden room.

I have considered all the submitted evidence and the Appeal Planning Officer’s report and on that basis the appeal is dismissed in relation to the dormer, hip-to-gable extension, rooflights, and single-storey extension, and the appeal is allowed in relation to the garden room.