Erection of a hip to gable roof & rear roof extensions approved in Wandsworth

Understanding Planning Permission for a Rear Dormer and Mansard Roof Extension

Extending a home in Wandsworth with a hip-to-gable and rear dormer or mansard roof extension can be a complex process due to the borough’s strict planning policies. While these types of loft conversions offer significant additional living space, navigating Wandsworth Council’s planning requirements presents unique challenges.

Design and Character Considerations for a Rear Dormer and Mansard Roof Extension

Wandsworth Council places a strong emphasis on preserving the character and visual harmony of residential streets. According to the Housing SPD (2016), roof extensions must be sensitively designed to maintain the architectural integrity of the area. This often means that rear dormers should be set down from the ridge of the roof and in from the eaves, while mansard roof extensions should follow a uniform and traditional design approach.

For properties in conservation areas, planning constraints are even tighter. In such cases, Wandsworth typically resists large-scale roof alterations that could disrupt the historic streetscape. Even outside conservation areas, planning officers assess applications based on how well the extension integrates with surrounding properties. A bulky or disproportionate rear dormer might be refused on the grounds that it negatively impacts the street scene or creates a sense of overdevelopment.

Neighbour Considerations for a Rear Dormer and Mansard Roof Extension

One of the primary concerns when applying for a dormer or mansard extension in Wandsworth is its potential impact on neighbouring properties. The council carefully evaluates whether the proposal affects neighbours’ privacy, daylight, and outlook. A rear dormer that overlooks neighbouring gardens or results in overshadowing could lead to objections from both planning officers and neighbours.

To mitigate this risk, applicants often need to provide detailed plans demonstrating that the extension will not result in significant loss of light or create an overbearing presence. Some applications benefit from a sunlight and daylight assessment to support their case.

Permitted Development vs. Full Planning Permission for a Rear Dormer and Mansard Roof Extension

In some cases, a rear dormer extension may fall under permitted development (PD) rights, meaning it does not require full planning permission. However, mansard roof extensions generally do not qualify under PD and require a full planning application if the height of the existing roof is raised, or if the volume exceeds the amount allowed under permitted development. Even where PD rights apply, homeowners must ensure their plans meet specific size and design criteria. If the property has been previously extended, or if it is a flat or maisonette, PD rights may not be available at all.

Ensuring Approval for a Rear Dormer and Mansard Roof Extension in Wandsworth

Given these challenges, a successful application requires a carefully considered design that aligns with Wandsworth’s policies. Engaging an experienced planning consultant can help navigate the process, ensuring that proposals are both compliant and optimised for approval. By addressing concerns over design, scale, and neighbour impact from the outset, applicants can improve their chances of securing planning permission while maximising their home’s potential. 

Get in touch with 4D Planning today for a free consultation and to discuss the feasibility of your extension.