The client sought a flat built entirely under his terrace-house garden, making the existing property more suitable for his growing family whilst retaining the garden. Within 46 m², the project required resourceful use of space, ingenious access to natural light and preferably little impact on the adjacent properties and environment.
A concrete shell was inserted below ground, and a glass cube dropped into the centre, drawing in light and air and creating both a lightwell and private courtyard. Flat, walk-on roof lights were installed in the bathroom and hallway ceilings to further maximise natural light. To counter space constraints, Edgley Design established a careful, simple layout, with frameless glass and minimal details. The garden was then reinstated over the top in three landscaping zones that further defined the building’s appearance: a low-level patio adjacent to the basement bedroom, steps up to a deck and a grass garden area beyond.
The finished product increases the site’s density without reducing the amenity of the rear garden. Being an underground structure, it is a quiet residence with exceptional sound insulation and reduced water runoff. The shell of concrete provides a high level of thermal mass that absorbs internal heat in summer and insulates stored heat in winter, which reduces CO² emissions and energy use. Having not substantially raised the level of the garden, the adjoining homes’ views and light levels have not been impacted; the green roof and landscaping make it virtually invisible from neighbouring properties. The green roof, installed with a 200mm substrate system, is deeper than standard, allowing the lawn grass to grow naturally. Inside, sliding partitions permit flexible living, sleeping and kitchen areas, giving the ability to customise an altogether harmonious layout. All the doors and windows were built bespoke using either solid walnut (external) or zebrano veneer (internal).
