Takero Shimazaki Architects has claimed the highly coveted 2025 Manser Medal – AJ House of the Year for their stunning Niwa House project in south London. The innovative residential design impressed judges with its exceptional architectural qualities, earning praise with descriptions such as "awesome," "exquisite," "super-calm," and "super-zen." The award represents the pinnacle of recognition for new-build or significantly extended residential projects in the United Kingdom.
Niwa House showcases a distinctive lightweight, pavilion-style design consisting of a single story with basement levels. The structure sits strategically behind a row of terraced houses on what was previously a derelict and contaminated plot of land, formerly occupied by a glass manufacturer's warehouse that required extensive environmental remediation before construction could begin.
The home's fully accessible design draws significant influence from traditional Japanese architecture, featuring an exposed timber frame arranged around a continuous series of flowing spaces. The layout seamlessly connects interior and exterior environments through full-height glazing that opens to an enclosed garden and below-ground level courtyards. Controlled natural light enters the living spaces through carefully positioned overhead skylights and clerestory windows, creating an atmosphere of tranquil illumination throughout the day.
"Compositionally, all the spaces were really well-resolved: uses were clearly defined yet flowed," commented one judge during the evaluation process. Another judge added that "as a structure, it beautifully framed the way the family live," highlighting how the architecture enhances daily life for its residents.
The innovative hybrid timber and stone structural system, developed in collaboration with structural engineers Webb Yates, represents a masterpiece of sustainable engineering. The construction features glulam oak columns supporting an intricate network of stacked beams, which in turn support a thick limestone ceiling that provides essential thermal mass and structural rigidity. Remarkably, the fabrication method allows for future disassembly and complete reuse of both timber and stone components, demonstrating forward-thinking sustainability principles. One judge particularly appreciated this aspect, commenting, "Loved the jenga-style beam/stone interfaces."
Internal comfort within Niwa House is achieved through a sophisticated balance of passive and active environmental control measures. The design incorporates the stone's natural thermal mass properties, green roofs for insulation and stormwater management, triple-glazed windows for optimal energy efficiency, air source heat pump (ASHP) systems, and mechanical ventilation with heat recovery (MVHR) systems. Despite its minimalist aesthetic approach, judges found the home remarkably livable, with one concluding, "For all its minimalism, it felt very much a lived-in house – the homeliest of the houses we saw."
The Manser Medal – AJ House of the Year specifically champions architectural excellence in new-build or significantly extended and refurbished residential projects across the UK. This year's competition featured eight exceptional finalists, all of which were personally visited and evaluated by an expert judging panel. The distinguished panel comprised Teresa Borsuk, senior advisor at Pollard Thomas Edwards; Kieron Taylor, design director at AKT II; and Giles Wheeldon, associate director at Ian Chalk Architects.
The long-standing prize honors the memory of renowned British architect Michael Manser (1929-2016), a former RIBA president and Royal Academician who made significant contributions to British architecture throughout his career. The 2025 AJ Architecture Awards winners, spanning 19 distinct categories plus three editorially-chosen special awards, were announced during a celebratory dinner event held at the Royal Lancaster London on November 27, 2025.
Niwa House represents exceptional value in sustainable residential design, with a gross internal floor area of 365 square meters completed in July 2024. The project demonstrates remarkable energy efficiency with operational energy use of just 31.89 kWh per square meter per year and an embodied carbon footprint of 647 kgCO2 per square meter. The home achieved an impressive Energy Performance Certificate rating of B (88), though it currently has no on-site energy generation systems.
Among the other notable finalists, Catching Sun House by studioshaw received high commendation for its innovative approach to capturing natural light in a constrained urban environment in Walthamstow. The project, completed in January 2024 with a construction cost of £400,000, impressed judges with its honest, stripped-down design approach and clever use of articulated roof forms and clerestory windows to maximize daylight penetration.
Other remarkable finalists included A Contemporary Home for a Couple by Architects Group and Rural Solutions, which uniquely used decommissioned North Sea oil rig pipes as foundation piles and achieved 100% on-site energy generation through renewable systems. The competition also featured Black and Stone by Mallett, a stunning transformation of a ruined ploughman's cottage in Perthshire, and Clay Rise by Templeton Ford, a self-build home in West Sussex that beautifully echoes local vernacular architecture.
The diverse range of winning and finalist projects demonstrates the current excellence in British residential architecture, from urban infill projects to rural retreats, each showcasing innovative approaches to sustainability, design, and quality of life. These projects collectively represent the future direction of residential architecture in the UK, emphasizing environmental responsibility, design excellence, and human-centered living spaces.
