Roof extensions and alterations at 24 Cornford Grove, London SW12

“Above the three‑storey back addition, a mansard roof extension is proposed, measuring 3.3 m in depth with the rear and side slopes set back at 70-degrees. The extension would include a rear‑facing dormer window.”

“SITE DETAILS: The application site is a two-storey semi-detached property comprising two flats, with the current application relating to the units on the upper floors. It is located on the west side of Cornford Grove. The surrounding area is predominantly residential, and the street scene is generally characterised by semi-detached properties of similar design and massing. The property is neither statutorily nor locally listed and is not located within a conservation area.”

“22/12/2025: (2025/3925) Approved: Alterations including erection of single-storey rear/side extension. 19/10/2022: (2022/3069) Approved: Alterations including erection of a single-storey rear/side extension to ground floor 12/10/2016: (2016/4955) Approved: Alterations including erection of single-storey side extension. First and Second Floors Flat:”

“15/05/1975 (75/14834) Approved: Deemed consent for conversion into 2 self-contained flats.”

“OBJECTIONS: summarised as: • Impact on Symmetry and Character: Raising the ridge would disrupt the symmetry of the semi‑detached pair and harm the terrace’s character. • Excessive Height and Visual Incongruity: The increased height would appear noticeably higher than neighbouring properties and out of keeping with the established roofline.”

“Official Official • Precedent and Inconsistent Roofline Concerns: Past approvals only permitted ridge increases when both adjoining properties applied together; a single‑side increase could set an undesirable precedent. • Lack of Justification for Ridge Increase: Additional headroom could be achieved internally, so raising the ridge is not considered necessary.”

“The extension would therefore not harm the character of the host building and the spatial character of the rear setting and is considered acceptable in design terms. Overall, the proposal is not considered to have an adverse impact on the character and appearance of the dwelling or the character and appearance of the surrounding spatial character and is considered acceptable in design terms.”

“Fire Safety 3.1 Policy D12 of the London Plan (2021) requires all development proposals to achieve the highest standards of fire safety. In line with this policy, a fire strategy has been submitted for the minor residential development. The strategy outlines appropriate active and passive fire safety measures to be implemented on site.”

“Condition AC15 - Materials to match All external materials used in the construction of the development hereby approved shall match the type, texture, tone, colour, size and profile of those used on the existing building and shall be retained permanently.”

“Condition AC25 - Increased ridge height The increase in the height of the roof shall only be constructed by continuing the front roof slope in the same plane, and no upstand or step shall be formed. Reason: To safeguard the appearance of the streetscene in accordance with Council policies LP1 and LP2 of the Local Plan coupled with the requirements of the National Planning Policy Framework.”

“RESOLVED - (unanimous) that planning permission be granted as set out in the report.”