The original brief was to extend a 1970’s 250m2 family house, atop a hillside, one storey above a busy road located in Hampstead, London. Having lived in robust loft architecture in Manhattan our clients were drawn towards minimal modern. Our challenge was to reconcile this with family living, sustainability, and yet create a coherent uncompromised architecture.

Having started with modest designs for front and rear extensions, detailed investigation proved the original construction problematic, whilst our client was becoming more ambitious. Discussions about front access prompted us to invent a radical scheme: demolish the house, sink the site by a floor to road level, provide a new-build eco-home.

We divided the functional brief into sleeping and living to make a lightweight ‘twisted/distorted’ box clad in ‘burnt’ larch atop a half-buried heavyweight rendered base. The house folds into a series of split-level floors following the natural gradient of the hillside, we increased the floor area to 500m2 GIA.

The house is anchored vertically by the main stair wrapped through a 4-storey sky-lit atrium. This gets light deep into the plan with dramatic cross-communication between the ‘public’ living areas. At roof level, we revealed a surprise view across the sedum roof, looking south over London’s rooftops.

Through architectural exploration we moved the brief away from consciously minimal towards a robust and self-expressed honesty in construction and materiality. This fed comfortably into our sustainable approach; passive techniques using thermal mass such as exposed concrete slabs, high levels of insulation, closed upper facades to the street (that also kept out the traffic noise), natural light and low-sun penetration for winter-time solar gain, ducted air and heat-recovery. green roofs, rainwater harvesting, ground-surface permeability.

Our clients are amazed by how much their lives have been transformed since moving in. They talk about how they feel uplifted by moments, spaces and views, by the quality of air and natural light, not having to turn on lights in the day, not feeling tired like they used to, how they close the front door and hear birdsong coming from the back garden.

The sustainability of this house is discrete and indivisible from the architecture, but its combined effect is implicitly understood by the client and is a conversation way beyond the mere reduction of carbon emissions.