A mansard loft conversion and rear extension can offer more than additional floor area. At Alfriston Road in Wandsworth, our approved design reorganises the house from the ground floor to the roof, with a social kitchen and dining space, more private bedroom accommodation and a mezzanine that makes use of the height above a first-floor room.
Wandsworth Council granted householder planning permission on 23 March 2026 under application 2026/0327. The permission covers a mansard extension to the main rear roof and a part single-storey, part two-storey rear extension.
A garden-facing kitchen with room to gather
The ground-floor design places the kitchen between a separate front living room and a new dining and seating area at the rear. This gives the household a choice of spaces: somewhere quieter at the front, and a connected setting for cooking, eating and spending time together towards the garden.
A wide kitchen island includes seating and the hob, allowing cooking to remain part of the conversation. Pantry storage, a separate utility room and a WC support the shared space without asking it to accommodate every practical function. Shelving along the side of the rear room provides a place for books and everyday belongings.
Two rooflights sit above the extension, bringing light into the dining and seating areas. Aluminium sliding doors provide a broad view onto the garden, with the patio designed to meet the internal floor level. Together, the doors and rooflights are intended to make the rear room feel open to the outside throughout the year.
Using height as well as floor space
Upstairs, the scheme gives a first-floor bedroom a vaulted ceiling and its own stair to a mezzanine. This is a distinctive way to make more of the available volume: the room gains a separate raised area while retaining the sense of height beneath the roof slope.
The mezzanine is part of that bedroom’s layout. It is separate from the new loft bedroom, which has an en suite, cupboards and access to low-level storage. Considering these spaces together helps balance usable room space, storage and the routes between floors.
The first-floor arrangement also includes a rear bedroom with an en suite alongside a shared bathroom. More bathroom provision gives the sleeping accommodation greater flexibility and privacy, particularly when several people need to get ready at the same time.
A roof extension shaped around the house
The mansard brings the rear roof space into use, with two lead-finished dormers and roof tiles selected to match the existing covering. French doors with side glazing and a Juliet balcony serve the loft bedroom. These provide an opening and outlook from the room; the permission does not allow the extension roofs to be used as terraces.
At the back of the house, the single- and two-storey additions are finished in render to relate to the existing building. Their depth was developed with the neighbouring approved extension at number 75 in mind, aligning the rear additions at ground- and first-floor level. This gave the design a clear local context when considering its scale and relationship with adjoining homes.
Connecting the changes throughout the home
New stairs, repositioned access to the living room and basement, and cupboards around the stairways are part of the same design. These less visible changes help the new accommodation connect with the original house, so the benefit is felt in how rooms are reached and used as well as in their size.
If you are exploring a similar project, see our loft conversion design services and house extension services. Arrange a call to discuss your home and the opportunities for improving its layout.
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