If your London home has limited head height or an awkward roof shape that rules out a simple loft conversion, a mansard roof conversion could be the answer. By replacing one or both slopes of your existing roof with a near-vertical wall and a flat top, a mansard loft conversion creates a full additional storey of usable space, often with enough height and floor area for multiple new rooms.
Bespoke Lofts specialises in mansard loft conversions across London, working with homeowners to design a space that suits their property, their street, and their long-term plans. As one of the more involved forms of loft conversion, a mansard extension calls for careful structural design, an understanding of local planning policy, and a builder who has delivered this type of project before.
Want to know if a mansard conversion is the right fit for your home? Contact us at Bespoke Lofts to speak with our team. Get expert advice and a free, no-obligation quotation to envision your project with the right guidance.
A mansard roof takes its name from the French architect François Mansart, who popularised the design in the 17th century. Rather than a single pitched slope, a mansard roof has two: a steep, near-vertical lower slope (typically around 72 degrees from horizontal) and a much shallower, almost flat upper slope.
This structure allows the new space to sit closer to the edges of the building, maximising both head height and floor area compared with a standard dormer or hip-to-gable conversion.
Mansard loft conversions are particularly well suited to:
A mansard loft conversion alters the form and profile of the roof. It’s generally suitable for end-of-terrace, mid-terrace, and semi-detached houses where the rear elevation isn’t visible from the street, though each property should be assessed individually against local planning policy.
Bespoke Lofts has been designing and delivering mansard roof conversions in London for homeowners who want a genuinely full storey of new living space, not a compromise. We manage the entire project in-house, so you deal with one team from first sketch to final fitout, rather than coordinating separate architects, planning consultants, and contractors yourself.
Our turnkey mansard loft conversion service includes the following:
Most mansard extensions in London require planning permission. The structural demands rarely fall under Permitted Development. Having a construction team that understands London borough planning policy from the outset can make a meaningful difference to how smoothly your application progresses.
Speak with our team for a free survey and a fixed-price quote, with no obligation.
Whether you’re planning an extra bedroom with an en-suite, a family bathroom, or a self-contained space for a growing household, a mansard loft conversion gives you the head height and floor area to do it properly. Get in touch today, and we’ll talk through your property, your goals, and how a mansard conversion could work for your home.
Answers to some of the more detailed questions we hear from London homeowners considering a mansard roof conversion.
Most mansard loft conversions in London go for a bedroom with an ensuite. So yes, these additions indeed add to capital appreciation, especially in areas where larger family homes command a premium. The increase you’ll see depends on the local market, the quality of the finish, and the way the new space is used, so it’s worth talking to our team about your specific property before committing to a design.
In many cases, yes. Some London boroughs take a more favourable view of a mansard application where similar conversions already exist on the same terrace or street, as it can support the argument that the design respects the existing streetscape. This isn’t guaranteed, however, and each application is assessed on its own merits, so a pre-application check with the local planning authority is a sensible first step.
A mansard conversion typically involves building up to or along a shared party wall; a party wall agreement is usually required under the Party Wall etc. Act 1996. This means notifying your neighbours formally and, in some cases, appointing a party wall surveyor. Bespoke Lofts manages this process for you as part of our turnkey service.
Generally not. Unlike a rear extension, a mansard loft conversion builds upward within the existing footprint of the property, so it doesn’t reduce garden space or require excavation. This makes it a practical option for homes where outdoor space is already limited.
A mansard conversion generally offers the most usable floor area and head height of the common loft conversion types, since it replaces the roof slope rather than adding to it. This makes it better suited to projects that need two rooms, or a bedroom plus a bathroom, rather than a single additional room. A hip-to-gable or dormer conversion may be quicker and less disruptive, but a mansard is often the better fit where the brief calls for more substantial additional space.
