Appeal 3311255

The appeal is dismissed.

The main issues are the effect of the development on: • the character and appearance of the host building and surrounding area; and • the living conditions of the occupants of [address] with regards to outlook and light.

The appeal property is one half of a pair of two-storey, semi-detached houses located at the end of a row of similar houses on the west side of [address]. To the south is a row of terraced houses which are set further back from the road. The gap between the buildings is quite narrow and tapers further in towards the rear. Whilst there is currently a covered walkway structure which occupies the space to the side boundary, this is at ground floor level only and is set back notably from the front wall of the house, such that it does not unduly impose on the limited separation gap.

Policy DMHD1 of the Hillingdon Local Plan: Part 2 - Development Management Policies 2020 (the DMP) sets out various criteria for extensions to dwellings. Amongst other things, extensions should ensure there is no adverse impact on the character, appearance, or quality of the existing street, and achieve a satisfactory relationship with adjacent dwellings. Specifically for two-storey side extensions, these should be set in a minimum of 1 metre from the side boundary to maintain adequate visual separation and views between houses; and also set back a minimum of 1 metre behind the main front elevation.

As the proposed two-storey side extension would be built up to the side boundary and is only set back from the front elevation at first floor level, there is clear conflict with the relevant criteria of Policy DMHD1. Moreover, the effect would be a marked reduction in the visual separation between the buildings. This would cause the extension to appear uncomfortably cramped within the plot and particularly in relation to the neighbouring building, to the detriment of the spatial qualities of the area, albeit the harm would be very localised.

The limited width of the side extension, first floor set back, and lower roof height would ensure that the extension appears subservient to the host building when viewed from the street. In addition, the rear extensions are not excessively large, have limited public visibility, and I note that the Council had no objection to those elements of the scheme in design terms. However, this does not alter my findings in relation to the spatial effects of the two-storey side extension.

Therefore, as a result of the two-storey side extension, I find that the development would have an adverse impact on the character and appearance of the area. Although the harm would be localised, there is conflict with Policy DMHD1 of the DMP in this regard. I also find conflict with the more general requirements of Policy DMHB11 of the DMP; and Policy BE1 of the Hillingdon Local Plan: Part 1 [name] (2012), in so far as they require new development to harmonise with the local context by taking account of plot sizes and gaps between buildings; and to make a positive contribution to the local area in terms of layout, amongst other things.

The Council states that the proposed first floor rear extension would cause unacceptable loss of light and outlook from No 448’s first floor bedroom window on the basis that it would breach a 45-degree line from this window.

However, the guidance to Policy DMHD1 explains that the 45-degree rule is only a general rule of thumb and that there are two methods for applying the rule. Method 1 considers the depth and width of the extension; and Method 2 considers the height of the extension. The lack of explanation in the Council’s officer report means it is unclear how the 45-degree rule has been used in this case. In the absence of any firm evidence on this matter, a judgement is required.

According to the Council, the extension would be located approximately 1.3 metres off the common boundary with a projection of 3.6 metres. This is very similar to the existing first floor extension at No 448, which the Council must have deemed acceptable in relation to the appeal property. While this extension would be to the south of the neighbour’s window, its height in relation to the widow would be relatively low and the hipped roof would slope away from the boundary. This, combined with the distance from the boundary and a modest projection, would, in my judgement, be sufficient to ensure that the extension would not be unacceptably dominant, or cause any significant loss of light to the window in question.

I therefore find that the development would not materially harm the living conditions of the occupants of [address] with regards to outlook and light. Thus, the proposal complies with the residential amenity protection requirements of [name] DMHD1 and DMHB11. However, this absence of harm is a neutral matter in my overall assessment.

For the reasons given above, the proposal would harm the character and appearance of the area, and is therefore in conflict with the development plan taken as a whole. Accordingly, the appeal should be dismissed.