The design features a large garden facing kitchen window with wide bi-folding doors for exceptional indoor-outdoor flow under a sleek flat roof with a light-enhancing glazed roof light. The extension also incorporates practical supporting functions, including a dedicated utility area and a convenient ground floor WC, all carefully integrated with the existing plan layout. A sustainable green living roof increases the environmental credentials and insulation of the new structure, sitting comfortably alongside the original building. The focus was on creating a high-performance extension with meticulous attention to insulation and air tightness, ensuring exceptional thermal comfort within the new space, distinct from the thermal characteristics of the existing dwelling. The design carefully considered the proximity of adjoining properties to ensure no negative impact on their amenities, particularly regarding light and outlook from the original and proposed windows. As the builder undertook the works himself and managed the Building Regulation application, our role focused on providing a clear and buildable design package, including seamless integration details with the existing structure, facilitated by a necessary Party Wall Agreement with neighbouring properties.