The application proposed the construction of a ground floor rear extension, a rear loft dormer extension, an air conditioning unit, a new rooflight and SVP to the front roof slope, and the conversion of the garage into occupiable space at 11 Hurley Crescent, London SE16 6AL.
The site is located on the southern side of Hurley Crescent, overlooking Dock Hill Avenue. The dwelling forms part of a development originally granted consent in 1984, which removed permitted development rights precisely to preserve the urban design principles of the scheme — specifically, the strong use of perimeter blocks, well-defined rear gardens, and integrated garages that gave the development its distinguished character. Permitted development rights were removed from the consent to protect these principles.
The client contacted Planning Voice after a neighbour on their street submitted a planning application for a double-storey extension. Living in close proximity to the application site, the client was concerned about the potential impact of the proposed works on their property. The scale of the extension, involving development across two storeys at the rear, raised immediate worries about loss of natural light, increased overlooking into their private garden and habitable rooms, and a more enclosed and overbearing environment along the shared boundary. The client wanted to understand whether the proposals breached accepted planning guidelines and sought professional support to prepare a formal objection that would carry weight with the council's planning officers during the assessment of the application.
Planning Voice prepared a four-ground objection addressing loss of light and overbearing impact, character and design, noise from the proposed air conditioning unit, and the loss of parking.
The proposed ground floor rear extension was assessed against the 45-degree rule — a guideline adopted by Southwark and widely by planning authorities to assess the impact of proposed extensions on neighbouring properties' access to light. The proposed extension crossed the 45-degree line drawn from the nearest window of the adjoining property at No. 12 Hurley Crescent. This breach indicated a significant potential for loss of light to a property that already suffered from overshadowing, as the photographs submitted with the application itself demonstrated.
We also raised the cumulative overbearing impact of the combined rear extension and dormer addition. The narrow plot widths in this part of Hurley Crescent meant that both the scale and the massing of the proposals — taken together — would create an excessive sense of enclosure for the adjoining occupiers, contrary to Local Plan Policy P56 and London Plan Policy D6.
The removal of permitted development rights in the original 1984 consent was a deliberate planning mechanism to protect the design integrity of the scheme. Any alteration therefore required full planning consideration against the original design principles, not merely against general design policy. The proposed garage conversion, rear extension and dormer, taken together, would erode the coherence of the perimeter block design, the consistent roofscape, and the integration of garages that defined the character of the development.
The installation of an air conditioning unit on the front roof slope, in close proximity to the neighbouring dwelling, raised concerns about noise and disturbance. No acoustic assessment had been submitted with the application. Given the proximity to the shared boundary and the residential context, an independent noise assessment was required before the council could be satisfied that the proposal would not cause unacceptable harm to the amenity of neighbouring occupiers.
The conversion of the garage to occupiable space would remove an existing off-street parking space from a street where on-street parking was already under significant pressure. This loss was contrary to the parking retention policies in the development plan and would directly worsen conditions for residents of Hurley Crescent.
Following Planning Voice's objection, the application was amended. The revised scheme addressed the most significant concerns raised — particularly the loss of light and the overbearing impact of the rear extension — by reducing the scale and footprint of the proposed works. The amendments represented a meaningful improvement over the original submission.
The 45-degree rule is one of the most consistently applied tools in residential extension assessments. Demonstrating a clear breach, supported by reference to the BRE daylight guidance and any existing overshadowing context, provides a strong factual basis for an objection. This case also illustrates the importance of original planning conditions — where permitted development rights have been removed, any extension must be assessed against the full planning policy framework, not simply assumed to be acceptable because it would have been permitted development elsewhere.
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