Appeal 3301073

The appeal is dismissed.

The main issue is the effect of the proposal on the character and appearance of the host dwelling and area.

The appeal dwelling is located on [address] at its junction with [address]. Nearest to the site, [address] is generally characterised by two-storey semi-detached and terraced buildings of similar designs including catslide roofs that extend out over set-back single-storey side projections. Some extensions and alterations are visible, but the original form of the buildings typically remains readable, and there is a high degree of consistency in their overall appearance which is distinctive.

In accordance with requirements specified within Policy DMHD 1 of the Hillingdon Local Plan: Part 2 – Development Management Policies 2020 (‘LPP2’), the side extension would be set back 1m from the main front elevation of the appeal dwelling and set in 1m from the boundary to the side of the site. However, its width would far exceed half the width of the original property at first-floor and roof levels, in conflict with the requirement at part C)i) of Policy DMHD 1. While the roof of the extension would be slightly set down from the main roof, the increase in the bulk and mass of the upper part of the dwelling would be substantial, and the considerable scale of the extension relative to the host property means that I find it would not be a subordinate addition.

In addition, the rear dormer would be far wider than the original roof at second-floor level in conflict with Policy DMHD 1 of the LPP2 which states that roof extensions should not exceed more than two thirds the average width of the original roof. The appellant asserts that the dormer would be modest scale in comparison to the width of the proposed dwelling. Nevertheless and notwithstanding the set back from the eaves and set in from the sides of the roof, the dormer could not in my judgement reasonably be described as subservient to the scale of the existing roof, and it would further add to the considerable increase in the overall bulk and mass of the building.

Taken together, I find that the dormer and side extension would result in oversized and disproportionate additions that would dominate and overwhelm the appeal building. Moreover, the proposal would result in the wholesale loss of the distinctive catslide roof to the side of the dwelling. In combination with the scale of the development proposed, this would undermine the character and integrity of the building on the appeal site, and the hipped roof over the side extension would stand out against the more typical catslide roofs to this part of [address].

The upper part of the dwelling would further be of much greater overall width than others nearby, and the considerable increase in scale of the building and loss of the catslide roof would unbalance the host terrace as a whole and harmfully erode the visual unity of this part of the street scene. The side extension would also step much closer to [address] than the front of dwellings to the rear of the site. Despite the set back of the extension from the front elevation facing [address], this would result in a significant reduction in space around the corner and would increase the visual impact and prominence of the development, particularly in views along [address].

Irrespective of the external finish of the building, I find for these reasons that the scale and form of the dwelling would be conspicuous, and the development would stand out as an incongruous and poorly integrated addition.

The appellant has drawn my attention to examples of large dormers at [address] and [address] nearby. However, these are typically at first floor level and are set within retained original catslide roofs which helps to reduce the overall increase in the bulk and mass of the buildings and the visual impact of these developments on the host properties and area. These examples are not therefore directly comparable to the appeal proposal, and they do not offer a compelling justification for the harm that I have identified. Nor do I find that the harm would be outweighed by the modest benefits of the development in providing additional living space for occupiers of the dwelling

For these reasons, I conclude that the proposal would cause significant harm to the character and appearance of the host building and area and it would conflict with Policy BE1 of the Hillingdon Local Plan: Part 1 – [name] 2012 and [name] 11, DMHB 12 and DMHD 1 of the LPP2. Amongst other things, these policies together broadly seek good design, development that harmonises with the local context, and subordinate extensions that do not adversely affect the character, appearance or quality of the area.

The proposal would conflict with the development plan when it is read as a whole, and material considerations do not indicate that a decision contrary to the development plan should be reached. I therefore conclude that the appeal should be dismissed.