Lantern House is a whole-house retrofit and rear extension to a substantial family home in Barnes, South West London. The clients came to JHA with a clear ambition — to transform a dark, compartmentalised Victorian house into a generous, light-filled home that worked for the way their family actually lived. The result is a project that achieves exactly that, centred on a new open-plan ground floor space anchored by a signature glazed lantern rooflight.

The lantern sits above the junction between the existing building and the new rear extension, drawing daylight deep into the plan and creating a dramatic focal point at the heart of the home. Below it, the kitchen, dining and living spaces flow together as a single generous room, connected to the garden through a full-width glazed facade. The quality of light throughout the day — from the sharp morning sun that rakes across the stone floor to the soft evening glow through the rear glazing — was considered at every stage of the design.

The retrofit scope was comprehensive. The existing building fabric was stripped back and rebuilt to a significantly higher thermal standard — new insulation throughout, improved airtightness, triple glazing to all principal elevations, and an all-electric heat pump system replacing the original gas installation. The project achieves a dramatic improvement in both running costs and comfort, without any compromise to the spatial or material quality of the finished home.

The material palette is warm and considered — a Flemish-bond brick to the rear extension, lime render to the existing walls, natural stone flooring, and carefully detailed oak joinery throughout. JHA coordinated the full consultant team including ICE Structures and delivered the project from first concept to handover in 2025.