Appeal 3368983

The appeal is allowed and planning permission is granted for the erection of a double-storey side and loft extension at [site address] in accordance with the terms of the application, [name]/2025/0544, subject to the following conditions:

The development hereby permitted shall begin not later than 3 years from the date of this decision.

The development hereby permitted shall be carried out in accordance with the approved plans: [name] 26CS/SLBLKPLN [name], 26CS/EELNS [name], 26CS/EPLNS [name], 26CS/PELNS [name] and 26CS/PPLNS [name].

The materials to be used in the construction of the external surfaces of the development hereby permitted shall match those used in the existing building.

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

The appeal property is a two-storey, semi-detached dwelling occupying a triangular shaped plot on the outside of a bend where [address] turns through almost ninety degrees. The area is entirely residential in nature comprising broadly similar type and aged properties. The appeal proposal would comprise two separate elements involving a loft conversion through a hip-to-gable change to the roof and a rear dormer extension, and the erection of a two-storey side extension.

During my visit I observed a number of properties along [address] that had been altered to the side in a variety of ways, including those with hip-to-gable changes and two-storey side extensions with significant variation between each in terms of form and scale. I saw most had been undertaken independent of the attached neighbouring property such that original symmetry between many semi-detached pairs has been lost and I found to be no longer a defining character feature of the area, especially where such changes were so prolific in close proximity to No 26, including at the attached property at No 24, which is extended to the side at two-storey. As such, the semi-detached pair already appears unbalanced. The proposal would not create any new imbalance, or one that was not already part of the street scene, but would merely alter its current form, adding to the area’s existing mix. Neither the hip-to-gable change, nor the addition of a two-storey gabled extension, would be alien or out of keeping with the character or appearance of the area as it has evolved over time.

The Hounslow Character, Sustainability and [name] A5 [name] (May 2024) advises that side extensions should normally be set back at least 1m from the original front house wall in order to prevent a ‘terracing effect’ and to allow the original proportions of the building to remain the prominent feature. This would be achieved at first-floor level but at ground floor the side extension would project forward to align with the dwelling’s front wall under a lean-to tiled roof. Nevertheless, given the appeal site’s corner position and the plot’s excessive frontage width, there would be no prospect of any terracing effect in this instance. Furthermore, the dwelling’s characteristic front projecting gable with a long-sloping roof and ground-floor level eaves would remain sufficiently evident as a feature in order to successfully help define the dwelling’s original proportions.

The SPD further advises that the height and width of two-storey side extensions should be proportionate and subordinate to the dimensions of the main house and that the width should be less than half the width of the house and the roof should be set down from the original roof by at least half a metre. The roof of the side extension would comply, but its width would exceed half that of the dwelling. However, it would not be excessively wide and in my judgement the side addition would appear neither overly bulky nor intrusive but instead would be seen to be appropriately subordinate and proportionate to the original dwelling. My opinion on this is aided further by the plot’s size, which offers an opportunity to accommodate an extension of the width proposed within an uncharacteristically spacious setting along [address].

Overall, whilst the side extension would contravene some of the SPD’s guidelines, I am satisfied that its overarching aims and objectives for avoiding harm to the character of the area and neighbouring properties would not be undermined in this instance.

In addition, I note that an equivalent hip-to-gable change with three front rooflights and a rear dormer extension was deemed to be permitted development through the grant of a Certificate of Lawfulness in November 2024 ([name]/2024/3253). I have no reason to doubt that such works would likely take place regardless of the outcome of this appeal, where a similar degree of imbalance with No 24 and visual change to the street scene would occur. This is a material consideration that also carries weight in favour of the proposal.

When all of this is considered, I am satisfied that the development would not harm the character or appearance of No 26 or that of the wider area. As such it would display the design quality that is required by Policies CC1, CC2 and SC7 of the Hounslow Local Plan 2015-2030 in order to respect the distinctiveness and context of the area, and to preserve the character and appearance of the host property.

In addition to the standard time limit condition, a condition requiring the development to be carried out in accordance with the submitted plans is necessary for the avoidance of doubt and in the interests of proper planning. A condition requiring the materials used to match the existing is also necessary in the interests of safeguarding the character and appearance of the area.

For the reasons given above, the appeal is allowed.