Appeal 3343038

The appeal is dismissed.

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

No. [site address] is on a corner plot located at a road junction with The Crossway. Much of the dwelling is visible from the surrounding roads. The area is predominantly residential with a traditional suburban character. It is mainly comprised of semi-detached and detached dwellings which are generally two storey. Dwellings tend to be set back from the road behind front gardens which often serve as off-road parking.

No.[address] is located to the west of the appeal site on the opposite side of The Crossway and on the corner of [address] and The Crossway. This is a detached two storey dwelling without a side extension to its east side (it has a single storey side extension to its west side). Both the appeal site and no.26 have similar (not identical) characteristics and contribute a modicum of ‘balance’ to this part of the streetscene.

A number of properties in the area have been subject to extension and alteration including loft conversions. Many of these extensions and alterations reflect the established character of the area.

The appeal site is a two storey semi-detached property with additional accommodation in a large rear roof dormer where a hip to gable roof extension has taken place. This dormer has been built (apparently recently) with a full height window with Juliette balcony and this is not reflected in the “existing rear elevation” drawing that has been submitted with the application. The appeal site has a single storey side addition which has garage doors at the front.

The proposed single storey rear extension would be about 3.6 metres deep and have a maximum height of about 4 metres. It would have eaves at about 2.5m and a mono-pitch roof. Policy DMHD 1 of the ‘London Borough of Hillingdon Local Plan Part 2 – Development Management Policies’ requires single storey rear extensions with pitched or sloping roofs to not exceed 3.4m in height measured from ground level. The proposed rear extension would exceed that requirement and given its proposed width at about 9.6m and the fact that it almost reaches the sills of the first floor windows, it would result in a dominant and bulky rear elevation to the host dwelling. The proposed side extension would be wider than the existing side addition by about 0.95m and consequently the width of the proposed rear extension would be as much as 9.6m. The impact of the rear extension as proposed would therefore be out of scale and would fail to achieve a harmonious and sympathetic rear elevation.

The proposed side extension would be set down from the main roof ridge and would have a pitched hipped roof. Policy DMHD 1(C)(vi) in relation to side extensions states that where hip-to-gable roof extensions exist a two storey side extension will not be supported. The proposed side extension would be lower than the main roof ridgeline but it would appear as an add-on rather than successfully integrating with the original host dwelling. The two different roof profiles on each element are difficult to integrate and the proposed design falls short of producing a convincing design. It would also add to the cumulative bulk of the property to the detriment of its appearance. There would be a clear breach of policy DMHD 1 and I have attached particular weight to that policy.

Impacts on visual amenity of the streetscenes of both [address] and The Crossway would be detrimentally affected by the disproportionately large and high rear extension and by the awkward relationship of the proposed side extension with the main dwelling. Much of the proposed development would be visible and prominent from the streetscenes and there would be a loss of balance of the two corner properties (the appeal site and no.[address]) which currently contribute to the rhythm of the streetscenes. 10.I have borne in mind the findings of a previous Inspector (ref APP/R5510/D/23/3329055) who was considering a proposal for a two storey extension to the side and part single storey, part double storey extension to the rear at the appeal site. I note that, amongst other things, she found that to rear the massing of the proposed extension coupled with the overall height would have the effect of adding significant bulk to the dwelling. She found that the design of the rear extensions would result in harm. However, from the front she came to the view that the two storey side extension would complement the existing dwelling. I am determining a different proposal and have considered its individual merits. In respect of the proposed two storey side extension before me, for the reasons I give above, I do not consider that it would be visually acceptable including from the principal elevation. 11.I conclude therefore that the proposed development would substantially harm the character and appearance of the host dwelling and surrounding area. It would conflict with policy BE1 of the Hillingdon Local Plan: Part 1 - [name] (adopted 2012) and policies DMHB 11, DMHB 12 and DMHD 1 of the Hillingdon Local Plan: Part 2 - Development Management Policies (adopted 2020).