Appeal 3301178

The appeal is dismissed.

The main issue is the effect of the proposal on the character and appearance of the host property and the area, including whether it would preserve or enhance the character or appearance of the Canons Park Estate Conservation Area.

Section 72(1) of the Planning (Listed Buildings and Conservation Areas) Act 1990 states that in respect of development affecting conservation areas, special attention shall be paid to the desirability of preserving or enhancing their character or appearance. The National Planning Policy Framework 2021 (‘Framework’) sets out that harm to the significance of a designated heritage asset, such as a conservation area, should require clear and convincing justification.

Collectively, and amongst other things, Policy HC1 of the London Plan 2021 (‘LP’), Policy CS1.D of the [name] 2012 (‘HCS’) and Policy DM7 of the Harrow Development Management Policies 2013 (‘HDMP’) require development to conserve and enhance heritage assets, and seek to resist proposals which would harm their significance. Those policies thus reflect the statutory test, and are consistent with the stance in the Framework.

The site falls within the Canons Park Estate Conservation Area (‘CPECA’). This area is characterised by low density housing, set amongst landscaping, and parkland and water features associated with the [name] listed mansion. As described in the Canons Park Estate Conservation Area Appraisal and [name] 2013 (‘CPEMS’), the houses here were laid out as a formally planned [name], in a variety of designs, displaying good architecture, with many in the ‘Tudor revival’ style.

[site address] is consistent with the description above. The houses here are two storeys high and set back from the road behind front gardens. They typically have an articulated form, with fairly steeply pitched hipped or gabled roofs, and they display ornamental design features such as exposed timber beams, vertically hung tiles and two storey bay windows. They are faced with a palette of materials, including render, timber and sections of brickwork, often together on the same building.

In that context, and notwithstanding the individuality of the buildings, No [site address] stands out as something of an anomaly in the streetscene. Its principal elevations are faced almost entirely in red brickwork, it has a simple rectilinear form, and displays little architectural embellishment. Given those characteristics, the Council describes its style as modernist.

At some point No [site address] was provided with a hipped roof, but given its very shallow pitch it is barely visible from the road. Consequently, and notwithstanding other alterations, such as an open front canopy and car port, a rear conservatory, and replacement windows, the building retains much of its original form and appearance. Whilst not as striking as [address], in my view it still exudes a modernist style. Although not statutorily or locally listed, nor specifically mentioned in the CPEMS, it nonetheless contributes to the significance of the CPECA.

The proposed main roof, with a much steeper pitch than existing, would be more consistent with the roof form of some other properties in the road. [name] have not been provided with a streetscene elevation, I am not persuaded that its mass at roof level would appear markedly greater than adjacent properties. In that regard, and on the basis of the available evidence, the roof’s height and bulk would not be out of proportion with its neighbours, and it would not undermine the area’s spacious qualities.

However, that prominent hipped roof would be markedly at odds with the style and form of this modernist building, as would the porch with its brick piers, glazing and pitched roof, in place of the simple canopy.

The proposed extension above the office would be similar in height to the garage on the host’s opposite flank, and its parapet wall with a flat roof behind, would broadly respect the rectilinear shape of the original building. However, given that that part of the house projects well forward of its principal elevation, the raised wall would be prominent from the road.

As a result of that, and given the mixed form of the proposed extensions, the resultant building would have a very eclectic and incoherent appearance in the streetscene. The scheme would respect neither the host’s modernist style, nor fully reflect the appearance of the other houses in the road. Finishing the windows in black, similar to those at [address] and at 15 [site address] , would do little to alleviate that harm.

Part of the significance of the CPECA derives from the buildings’ coherent and high quality architecture. Whilst conservation area designation should not prevent appropriate alterations and extensions, for the above reasons, those proposed here would significantly harm the character and appearance of the host property and the area.

Consequently, the scheme would conflict with LP Policy HC1, HCS Policy CS1.D, and HDMP Policy DM7. It would also conflict with those parts of LP Policy D3, HCS Policy CS1.B, and HDMP Policy DM1, which more generally require development to respect the host building and to display a high standard of design that responds positively to local distinctiveness and character. It would also fail to comply with the advice in the [name] Planning Document 2010, which states that extensions should harmonise with the architectural style of the original building and the character of the area, with roof form requiring particularly careful consideration.

The scheme would also conflict with the Framework’s requirement for good design as a key aspect of sustainable development, and for development which is visually attractive and sympathetic to local character.

The harm to this designated heritage asset is a matter to which I attribute great weight. However, as the harm would be less than substantial, in accordance with the Framework I am required to weigh it against the public benefits of the proposal.

The proposal would provide additional living accommodation for the current, and future, occupants. That includes an enlarged living room and kitchen at ground floor to the rear, and accessible bedrooms and bathroom for the appellants along with their dependent relatives and carer. However, I am not persuaded that this scheme, with its significantly altered roof form, is the only way in which that benefit could be achieved. There would also be temporary economic and employment benefits during construction.

However, the significant harm that the scheme would cause to this designated heritage asset would not be outweighed by its very modest public benefits. In the absence of clear and convincing justification for that harm, I conclude that as well as conflicting with the development plan, the scheme would conflict with the Framework. It does not benefit from its presumption in favour.

Consequently, and having regard to all other matters raised, the appeal is dismissed.