A high-end terrace extension within the Cadogan Estate reimagines a constrained site in a conservation area. Planning restrictions prevented extending the primary stair to the new roof terrace, leading to the introduction of a bespoke timber spiral stair as a sculptural vertical element. The contemporary roof addition, finished in crisp white render, contrasts with the surrounding Queen Anne red brick context. The design enhances access, celebrates vertical movement, and delivers a refined architectural intervention that balances modern expression with its historic Chelsea setting.