This case concerned a planning application for a single-storey rear extension to a semi-detached house in Hayes. Although many rear extensions can be carried out under permitted development, the property is subject to an Article 4 direction which limits the depth of extensions that can be built without planning permission. As a result, a full householder application was required.
The proposal
The scheme involved the demolition of an existing rear addition and its replacement with a new single-storey extension across the full width of the house. The extension was designed with a stepped form, projecting to a depth of four metres along the boundary with the closest neighbour and increasing to a maximum depth of six metres further away, where it stepped in by two metres from the shared boundary.
The extension was modest in height, with an eaves height of around three metres and a maximum height of four metres, and was to be constructed in materials to match the existing house. It was intended to provide an improved family reception space at ground floor level.
The planning considerations
The main planning issue was whether the depth of the proposed extension would result in harm to neighbouring living conditions, particularly in terms of daylight, outlook and overbearing impact. Hillingdon’s local plan policies seek to ensure that residential extensions remain subordinate to the host dwelling and do not cause unacceptable harm to neighbours.
In this case, the design was informed by the existing site context. Both adjoining properties already benefit from rear extensions of varying depths, and there is mature boundary planting along the shared boundary with the closest neighbour. The stepped form of the extension was a deliberate design response to ensure that bulk was kept away from the neighbouring property most sensitive to impact.
Our approach
We advised on a design-led strategy that addressed neighbour amenity from the outset. This included careful control of height and depth, the stepped layout, and the absence of side-facing windows to avoid any loss of privacy. The planning submission also drew on relevant local precedents and appeal decisions where deeper rear extensions had been found acceptable in comparable circumstances.
The decision
The council granted full planning permission. The proposal was accepted as a proportionate and subordinate addition to the house which would not result in unacceptable harm to neighbouring occupiers.
If you have been advised that a rear extension is not possible because it exceeds local depth guidelines, or because your property is subject to an Article 4 direction, we can review the site and explain what may still be achievable.
If you are having difficulty getting permission for homeowner extensions, contact our lovely team for some advice.
It can be surprisingly difficult to get permission for extensions in Hillingdon. If you have already made an application for an extension and been refused, check out our Hillingdon planning appeals page for some advice.
