Appeal 3348589

The appeal is dismissed.

Although the air conditioning units have been erected, the appellant’s Noise Impact Assessment recommends the erection of acoustic screening as part of the proposal. Accordingly, reference is made to a proposed development.

It is considered that the main issue is the effect of the proposed development on the character and appearance of the host property and the surrounding area.

The appeal property is a detached dwelling which has recently been refurbished and is situated within a primarily residential area of detached houses and bungalows. The side elevation of the host property possesses a relatively simple appearance with the main architectural interest associated with the front elevation which includes a gable feature, porch and dormer window. The property is set back from the footway of [address] to the rear of a front garden which is landscaped and also used for parking.

The proposed development includes the erection of 8 air conditioning units with 2 located to the rear of the property and 6 erected at first floor level on the property’s side elevation. The council’s concern is directed primarily at the units erected on the side elevation which comprise [address] to the property’s front elevation with the other 4 units towards the rear of the property. The size of the side elevation is extensive and the erected air conditioning units do not physically or visually dominate this flank wall.

There is a gap between the side elevation of the property and the flank wall of [address]. This gap is between 3 and 4 metres in width. When walking southwards along the footways of [address], the erected air conditioning units are not visible until walking past the property. At this point, it is only the 2 units erected closer to the property’s front elevation which are visible albeit for a brief time.

Walking northwards, because of their siting and the proximity of No. 59, it is primarily the existing 2 units sited closer to the front elevation which are visible from the footway along the west side of the road for about 35 metres. The other 4 units erected on the property’s side elevation are only visible for around 15 metres. By reason of siting, the erected units are not so prominent nor conspicuous that they materially detract from the spacious and verdant character and appearance of the streetscene.

However, the appellant’s Noise Impact Assessment identifies that to comply with guidelines and to achieve the rating levels to avoid harm to the living conditions of the occupiers of the neighbouring property, mitigation is needed for the first floor level rear unit and the units on the side elevation. Concerns about noise levels have been identified by the occupiers of the neighbouring properties and the Council has suggested a condition to secure noise mitigation. No details about the size and siting of the recommended mitigation have been provided on any drawings and reliance is, therefore, placed upon the images included in the Assessment which identifies louvre type enclosures.

With the recommended mitigation identified, the proposed development at first floor level would project further away from the rear and side walls when compared to the existing situation. At the rear, the addition of the recommended mitigation would not adversely affect the character and appearance of the property. However, the potential size, bulk and elevation above ground level of the proposed mitigation for the 6 air conditioning units erected on the side elevation could cumulatively represent additions which are not subordinate to this flank wall.

Although their colour could match the wall’s rendering, the bulk and degree of projection of the recommended louvre type enclosures at first floor level could significantly affect the existing character and proportions of the host property which are matters referred to in [name] 1 and DMHB 11 of the Hillingdon Local Plan Part 2 (HLP2).

There would potentially be an increase in the visibility of the 4 units erected on the flank wall towards the rear of the property because of the bulk and size of the recommended mitigation. However, the screening afforded by the proximity of No. 59 means the degree of harm to the character and appearance of the streetscene could be modest and would not alone represent a reason for this appeal failing.

However, the siting and bulk of the proposed recommended mitigation could significantly increase the prominence of the 2 units sited on the flank wall of the property closest to its front elevation. This potential increase in visual and physical prominence would significantly detract from the character and appearance of the host property and the streetscene, including the positive contribution made by the property’s front elevation to the streetscene. The already identified modest harm associated with the recommended mitigation for the other 4 units would accentuate this unacceptable harm. For these reasons, the appeal scheme would conflict with HLP2 Policy DMHB 12 which requires development to be well integrated with the surrounding area.

Accordingly, and the in the absence of more detailed drawings, it is concluded that the proposed development would cause unacceptable harm to the character and appearance of the host property and the surrounding area and, as such, it would conflict with Policy BE1 of the Hillingdon Local Plan Part 1 (HLP1) and HLP2 [name] 11, DMHB 12 and DMHD 1. Amongst other matters, HLP1 Policy BE1 requires development to be of a high quality of design. Policy D3 of the London Plan is a generic policy about optimising site capacity via a design led approach rather than specifically addressing householder applications. However, this does not alter the conclusion that this appeal should be dismissed.