Niwa House

Set on a contaminated and constrained brown-field site behind a row of terraced houses, the property is designed to maximise floor area, whilst maintaining a low profile to respect height constraints. The primary structure, designed with Takero Shimazaki Architects, is influenced by Japanese architecture, evidenced by a primary oak glulam frame inspired by traditional Torii.

The main house comprises a single storey with basement, and a secluded single storey annex is created to the rear. The design also creates a serene planted garden out of a formerly weed strewn and barren site. Extensive remediation was required to resolve historic ground contamination.

The superstructure of the building is entirely timber and stone, with concrete only used for elements in contact with the ground. Composite timber and glulam have been employed for the roof to limit structural depths and avoid additional finishes, while the stone provides thermal mass. This is the first time that this approach has been used on a full-scale project. A green roof over the full-building footprint provides attenuation to support the drainage strategy.

Dynamic thermal modelling was adopted from an early stage to inform the architectural design development and materials selection to achieve the highest comfort levels and building performance. Passive design principles are adopted throughout to minimise heat losses in winter and heat gains in summer, reducing energy demand. These principles include the optimisation of the architectural shape, strategically placed openings to improve crossflow ventilation, external shades and blinds, exposed thermal mass, a high performing thermal envelope, and highly efficient glazing.