Do you need listed building consent for a rear extension on Cheyne Walk?

Yes. A Grade II listed property requires listed building consent in addition to standard planning permission, regardless of how modest the proposed extension is. For this project, Rosace secured both a householder planning application and listed building consent from the Royal Borough of Kensington and Chelsea, choosing a simple, standard-scale extension specifically to keep the heritage case straightforward.

How long did this project take, from first design to completion?

Planning approval, covering both the householder application and listed building consent, took around three months. The interior design and procurement that followed took considerably longer, six to eight months, reflecting the level of sourcing involved, including pieces brought in from Rajasthan, India, alongside London-based suppliers.

What was the approximate cost of this project?

Combined, the rear extension and full interior design, including procurement, came to around £600,000. Listed building projects carry costs beyond the build itself, heritage statements, specialist consultants and a slower, more careful build process all add to the total compared with an equivalent unlisted property.

Can Rosace deliver the interior design as well as the architecture?

Yes, interior design is in-house at Rosace, designed alongside the architecture from the first sketch rather than added afterwards.

Listed Building Architect Chelsea | Rosace Design Studio

The brief

The brief was more personal than technical: a little more room at the back of the house, and a redesign of the parts that had fallen out of use, rooms the client wanted to feel like their own rather than simply original to the building.

Given the property's Grade II listing and conservation area setting, Rosace's approach to the extension itself was deliberately restrained: a simple 30 sqm single storey rear addition, built in materials matched to the existing house rather than treated as an opportunity for contrast. The more expressive work happened inside. The primary bedroom was reworked in emerald green and white, the bathroom kept subtle in white tiling with a freestanding tub, and the informal living area given a warm chocolate and white palette, lifted with contrasting cushion covers to keep it from feeling too serious.

Planning context

This project required both a householder planning application and listed building consent from the Royal Borough of Kensington and Chelsea, given the property's Grade II listing and its position within a conservation area. Listed building consent adds a genuinely separate layer of scrutiny to a project like this: the council assesses not just the extension's scale and impact on neighbours, but its effect on the historic fabric and character of the building itself. Rosace's response was to treat the rear extension as a quiet addition rather than a statement, standard in scale and matched in material, which kept the application focused and reduced the risk of objection on heritage grounds.

Design & materials

Externally, the extension is built in standard London stock brick, chosen specifically to match the existing house rather than introduce a new material, a decision led directly by the property's listed status. Inside, oak flooring runs through the reworked rooms, grounding the new interior scheme in something warm and traditional. The rugs were sourced from Rajasthan, India, adding pattern and texture against the more restrained joinery and finishes, while furniture, lighting and fabrics were procured from designer stores across London, curated room by room rather than bought as a single scheme. Every material decision, inside and out, had to sit comfortably with a building the council was actively protecting, which shaped choices as much as the client's own taste.