Appeal 3370972

The appeal is allowed and planning permission is granted for alterations to unauthorised rear roof extension following appeal dismissal APP/H5960/C/23/3321800 at [site address] , London [postcode] in accordance with the terms of the application, Ref 2025/2110, subject to the following conditions: a) The development hereby permitted shall begin not later than three years from the date of this decision. b) 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. c) The development hereby permitted shall be carried out in accordance with the approved plans referenced: ‘Proposed Plans Section & Elevations’, [name]. ST_MAR 25_207 WIM_002. d) Prior to the occupation of the development the windows in the side elevation at the second floor level of the development shall be obscure-glazed and non-opening (unless the parts of the window which can be opened are more than 1.7 metres above the floor of the room in which the window is installed). The windows shall be maintained and permanently retained as such.

The Council revised the description of development, however the evidence that I have before me does not provide details of the appellant’s formal agreement to change the wording of the development description. Therefore, I have used the description of development provided on the application form.

I saw during my visit that a mansard roof extension above the appeal property’s main rear roof and a roof extension above its back addition had been erected. (This development was subject to a failed enforcement appeal1 in April 2025). This 1 Appeal Reference APP/H5960/C/23/3321800 appeal seeks amendments to the as built roof extension to the back addition. Since the development on the ground is not the same as that shown on the plans, I have dealt with the appeal on the basis that permission is being sought for the proposed development shown on the plans.

The Council has not raised any objections to the development in terms of its effect on the living conditions of neighbouring residents, highway safety or fire safety. Based on the evidence before me, and my observations at the site visit, I have no reason to take a different view.

Also, the Council has not raised any objections to the mansard roof extension to the appeal property’s main roof. Again, based on the evidence provided, and my observations at the site visit, I have no reason to disagree. I therefore consider the main issue in this appeal to be the effect of the proposed roof extension to the appeal property’s back addition (‘the outrigger roof extension’) on the character and appearance of the surrounding area.

No [site address] is a mid-terrace two-storey property in a residential area of similar terraced properties. Many of the properties in the street have been subject to incremental alterations and additions to the rear, particularly at roof level. This has resulted in a varied character with differences in the scale of additions with a noticeable lack of coherence or symmetry.

With regards to roof extensions to rear back additions, the ‘Wandsworth Local Plan Supplementary Planning [name] (SPD), adopted January 2016, says a good 'rule of thumb' is to extend over only 50% of the length of the back addition2. The SPD further explains that where there is more space between buildings and if there will not be any harm to any neighbour's amenities then an extension over the back addition can possibly be longer. But whatever the length of the extension the new structure should respect the scale, form and hierarchy of the rear addition and avoid appearing top heavy.

The appeal proposal seeks to reduce the depth of the as built roof extension above the outrigger by 1.7m, making it approximately 75% the length of the outrigger. As such, the original rear eaves line of the outrigger would be reinstated.

The rear wall of the outrigger roof extension would be 90 degrees (at odds with the advice in the SPD) and the neighbour’s outrigger roof extension, at [address]. However, in the context of the 90 degree wall to the outrigger of [address] and other 90 degree walls to roof extensions to the rear of the terrace, this would not look out of place. In addition, the hung tiles on the face of the wall would ensure that it would blend in with the property’s roof.

[name] acknowledge that the roof extension would be longer than the length recommended in the SPD, in the context of the street’s varied rear extensions and the absence of symmetry, and the mid terrace position of the dwelling (including the full depth extension to the outrigger at [address], which the Council accept appears to be lawful due to the passage of time) I find that the roof extension would not look out of place or top heavy. Its scale, mass and form 2 London Borough Wandsworth Housing SPD paragraph 4.165 generally complementing rather than conflicting with, the varied styles of the other rear extensions in the local area. For these reasons, the outrigger roof extension would be subservient in scale and would not be unduly dominant.

Consequently, I conclude that the proposed extension would not have a harmful effect on the character and appearance of the surrounding area. Accordingly, I find no conflict with Policies LP1 and LP5 of the Wandsworth Local Plan 2023-2038 or the SPD. These policies and guidance require development to be of high design quality, to relate positively to the prevailing local character, and, in the case of residential extensions, to be subservient to the host building and sympathetic in style.

To meet legislative requirements, a condition shall be imposed to address the period for commencement. I shall also impose conditions requiring compliance with plans, to provide certainty, and requiring the use of matching materials, in order to maintain the character and appearance of the host property and the area.

I agree with the Council that a condition is necessary to ensure that the windows in the side elevation are obscure glazed and non-opening unless above 1.7 metres above the floor of the room, to prevent overlooking and safeguard the privacy of the occupants of the neighbouring property.

For the reasons given above the appeal should be allowed.