Appeal 3349543

The appeal is allowed, and planning permission is granted for a rear conservatory at [site address] in accordance with the terms of the application, [name]/2024/0885, subject to the following conditions:

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

The development hereby permitted shall be carried out in accordance with the location map, block plan, existing elevations and proposed elevations.

The external surfaces of the development hereby permitted shall be constructed in the materials shown on the proposed elevations.

The extension hereby permitted shall not be occupied until the side windows have been fitted with obscure glazing, and once installed the obscure glazing shall be retained thereafter.

The main issues are the impact of the proposed development on: • the character and appearance of the host property and the surrounding area; and • the living conditions of no [address] with particular reference to shadowing, outlook and sense of enclosure.

The appeal site is located in a mixed residential and commercial area beside [address]. There are two storey terraced dwellings and a parade of shops on the appellant’s side of the road, and on the opposite side there are 2-4 storey period properties, one of which is a public house. [address] is characterised by large street trees which lend the road a sylvan quality.

The appeal property forms part of a grouping of three terraces, each of which contains four dwellings. The two outer terraces (nos 118-124 and nos 134-140) mirror each other, with two storey projecting gables on each end terrace property, whilst the central terrace (nos 126-132) features hipped gable projections and double height bays. To the rear of the outer terraces, the middle properties (which includes the appeal property) have two storey outriggers.

The appeal property has previously been extended with a two-storey flat roofed extension infilling the space between the rear outrigger and the boundary with no 124, and a single storey extension behind the rear outrigger. The appellant proposes to infill the area which links the two extensions, by building a single storey conservatory. There is already a section of brick wall on the boundary with no [address], with a short return behind the host property, which would be incorporated into the proposed conservatory.

The proposed conservatory would be a lightweight structure comprising a lean-to glass roof, clerestory glazing above the existing brick wall, and glass doors. The massing and roof form of the conservatory would be similar to that of the existing single storey rear extension, albeit at a slightly lower level, and the conservatory would consequently be subordinate to the main house. I note the presence of conservatories on other nearby properties, notably at no [address], which do not detract from the character of the area.

As a result, the proposed development would comply with the Council’s Residential Extension Guidelines Supplementary Planning Document (SPD), which guide that the height of a single storey rear extension should appear in scale with and subservient to the host dwelling. It follows that I am satisfied that, in regard to the SPD advice that conservatories added to existing extensions can raise design issues, no such design issues arise in this case.

Accordingly, I conclude that the addition of a conservatory would not be out of character with either the host property or the surrounding area, and would therefore comply with policies CC1, CC2 and SC7 of the London Borough of Hounslow Local Plan Volume One (LBHLP). Together these policies seek high quality urban design and architecture, including for residential extensions, which responds to local context and character.

The proposed conservatory would be positioned on the boundary with no [address], the adjoining terraced property. The conservatory would incorporate the existing brick wall on the boundary, such that the only additional elements of the conservatory which would be visible to the occupiers of no [address] would be the clerestory windows above the brick wall, and the glass panel on the side of the lean-to glass roof. The existing wall on the boundary would not be extended.

No [address] does not possess an outrigger, meaning its rear elevation aligns with the original rear elevation of the appeal property. It has rear facing windows which I am informed serve a living room and a kitchen, with access onto a paved patio which runs the entire width of the property and extends a significant distance into the rear garden. The two-storey extension which has previously been added to the appeal property causes a degree of shadowing of no [address]’s patio area and habitable rooms, and the existing boundary wall beyond that adds to the sense of enclosure at the rear of the property.

However, the works required to form the conservatory would increase the sense of enclosure only marginally, with additional shadowing minimised by the use of translucent materials. I have had regard to the advice in the SPD that rear extensions on terraced houses should have a maximum depth of 3.05 metres, and that single storey rear extensions should not project too far from the rear wall of the original house as this could cause unacceptable enclosure and block daylight received by neighbours. However, in this case the existing impact of the two-storey rear extension and side boundary wall is a significant material consideration, and consequently the incremental effect of the proposals would not be so significant as to harm the neighbouring property’s outlook.

I therefore conclude that the proposals would not have an adverse impact on the living conditions of no [address] and would therefore comply with policies CC2 and SC7 of the LBHLP, which together protect the living conditions of neighbouring residents from loss of daylight/sunlight, loss of outlook and an unacceptable sense of enclosure.

In the interests of certainty, I have attached a condition listing the approved plans. To ensure that appropriate materials are used, I have attached a condition requiring that the external surfaces of the development shall be constructed of the materials shown in the approved drawings,

I consider it necessary to attach a condition that the side windows of the conservatory are obscure glazed in perpetuity, as shown on the proposed elevations, in order to protect the privacy of the adjoining neighbour.

For the reasons given above the appeal should be allowed.