Coral Cube House

Cube House is an early 20th-century semi-detached home in Brockley, South London, remodelled by Selencky Parsons Architects and featured on Channel 4's Extraordinary Extensions. The steep site meant the entrance level sat a full storey above the garden, with a poorly laid-out rear extension and a lower ground floor that barely worked as livable space.

Cobalt rebuilt the two-storey rear extension on almost the same footprint, dropping the lower ground floor to open up a double-height space and giving the owners — who both work from home — a dedicated study that doesn't feel cut off from the rest of the house. Its centrepiece is a floating coral cube housing that study, finished in microcement that carries the same material from the kitchen straight through to the garden, with clear sightlines from the newly light-filled lower floor up to the balcony above.