Appeal 3270074

The appeal is dismissed.

An application for costs was made by the Appellant against the Council which is the subject of a separate decision.

The main issue in this case is the effect of the proposal on the character and appearance of the host dwelling and the De Beauvoir Conservation Area (CA) within which it sits, along with its effect on the levels of privacy enjoyed by the occupiers of No. [address].

The appeal relates to a traditional dwelling which sits at the end of a group of similar dwellings with smaller dwellings at either end, including the adjacent property, No. [address]. I understand that No. 148A is part of the appellant’s property. [address] is an attractive street of traditional properties which sits within the CA. A noticeable element of this particular section of the eastern side of the street scene is an absence of roof additions to the front of the properties.

The proposal seeks permission for a mansard roof addition, a first floor extension and a ground floor (above basement) extension along with fenestration alterations.

The first floor extension would sit above the existing ground floor (above basement) flat roof outrigger which connects with that of No. 148A. It would also have a flat roof and it would not be as deep as this ground floor section. It would be finished in timber cladding with a sedum roof. At my visit, I noticed a variety of two storey outriggers at the back of the properties within the row. Against this context, I am satisfied that the overall design and scale of this extension is satisfactory. I have no particular issue with the timber clad finish, which would give the extension a more contemporary appearance, although the Appellant explained that a brick finish would be agreeable. Whilst the Council has suggested that the proposed window to the rear elevation of this extension is not acceptable, a condition could be used to ensure that it matched the detailing of the existing windows of the host dwelling, rather than the 12-pane sash windows of nearby dwellings, which would not be reasonable.

The proposal includes an extension which would effectively infill the space between the existing projecting ground floor (above basement) section and the outrigger of the adjacent dwelling, No. [address]. This addition would also be contemporary in its appearance, with a predominant use of glazing giving it a ‘light appearance’, allowing views of the brickwork of the main rear elevation. Given the context I have described at the rear of this terrace row, I am satisfied that this element of the proposed scheme is acceptable in visual terms too.

The proposal also includes the addition of a mansard roof. The mansard would sit behind the front parapet and the Appellant asserts that its design follows the recommendations outlined within the Council’s adopted Supplementary Planning Document titled ‘[name] and Alterations’ (SPD). However, it would be the only mansard addition to the front elevation within this terrace row. To this end, I am mindful of the fact that the SPD explains ‘roof extensions are not normally acceptable in those terraces where an unbroken roofline remains’ (paragraph 3.85).

Whilst the row within which the appeal property sits does not contain a consistent cornice, the overall parapet roofline is broadly consistent, with the exception of the much lower properties located at either end of the row. Even accounting for the presence of some mature trees which provide a degree of screening from some vantage points, in this setting, the mansard would be conspicuous and would be seen as an isolated, prominent and incongruous feature within the roofscape.

I note the proposal includes the restoration of cornicing detailing to the front elevation of the appeal dwelling whilst the overall scheme would conceal pipework and services to the rear elevation. Nevertheless, I consider that the disruption to the roofline would harm the character and appearance of the host dwelling and the roofscape of the terrace within which it sits. As such, it would fail to preserve or enhance the character and appearance of the CA.

The harm to the heritage asset would be ‘less than substantial’ as directed by the Planning Practice Guidance, but I attach considerable importance and weight to the statutory duty imposed by section 72(1) of the Planning (Listed Buildings and Conservation Areas) Act 1990 that special attention should be paid to the desirability of preserving or enhancing the character or appearance of a Conservation Area.

The National Planning Policy Framework explains that when considering the impact of a proposed development on the significance of a designated heritage asset, great weight should be given to the asset’s conservation. It goes on to say that where a development proposal will lead to less than substantial harm to the significance of a designated heritage asset, this harm should be weighed against the public benefits of the proposal. This will be considered further below.

The proposed ground floor rear extension would project no further than the existing ground floor (above basement) section. It would project slightly beyond the outrigger of the attached dwelling, No. [address] and the projecting side section and rear elevation would be fully glazed. If this proposed extension had a floor in it, I would be inclined to share the Council’s concerns about the prospect of additional overlooking across the rear garden area of this attached property. However, this glazed section is a void, providing additional height and natural light to the living area below. [name] am mindful that the proposal includes the introduction of a set of bi-folding doors to the side elevation of the existing ground floor section, which would look across this void, there is already a large window to this elevation. I am satisfied that any additional overlooking arising from the bi-fold doors, through the glazed extension, would be limited and would be within acceptable parameters for such a high density urban setting.

On this basis, I conclude that the proposal would not result in an unacceptable level of overlooking for the occupiers of No. [address]. In this regard, I find no conflict with policy LP2 of the adopted Hackney Local Plan (LP), which seeks to safeguard appropriate levels of residential amenity.

The Appellant has not suggested that the proposed extensions and alterations would generate any public benefits. Nevertheless, the proposed development would result in the efficient use of urban property, creating a larger family dwelling which would better meet the needs of the Appellant and his family, including the additional demands generated by home working. To this end, the Appellant asserts that the proposal amounts to sustainable development. However, the National Planning Policy Framework explains that good design is a key aspect of sustainable development and I have explained why in this particular context, the proposed mansard does not amount to good design. Accordingly, this element of the proposal does not amount to sustainable development in the widest sense of the definition provided by the Framework.

The Appellant refers to several appeal decisions which relate to the introduction of a mansard roof. However, one of the fundamental principles underpinning the planning system is that each application is determined on its individual merits, taking into account the specific context within which the development would sit. Having carefully read my colleagues’ Decision Letters, there appears to be factors, such as broken roof lines, which justify the grant of planning permission in each case which do not apply to the proposal before me. Similarly, I have considered the other roof additions at Nos. 24 and [address] which also sit within the CA. However, these are some distance from the appeal dwelling and do not sit within the same context and setting. I have also considered the additions at Nos. 142 and [address], but these are not front facing mansards. I therefore attach only limited weight to these examples in the overall planning balance.

I find the ground and first floor rear extensions and associated fenestration alterations to be acceptable. However, the proposed mansard addition would harm the character and appearance of the host dwelling and the roofscape of the terrace within which it sits and it would fail to preserve or enhance the character or appearance of the CA. In such terms, this element of the scheme conflicts with policies LP1 and LP3 of the LP and the SPD, which collectively promote high quality design which respects and responds to local character and context and preserves or enhances heritage assets.

The arguments advanced by the Appellant do not outweigh this harm and associated policy conflict therefore the appeal does not succeed.

I have considered the possibility of issuing a split decision, but as the various elements of the scheme are not completely functionally independent, it would not be practicable to do so in this case.