We broke the building into two volumes, articulating the garden room, storage and sauna as distinct parts. In the garden room, large glazed sliding doors draw the garden inside, and a single wrap-over rooflight frames the woodland to the rear. We worked with interior designers Black & Milk on the fit-out, including the banya itself. The roof profile follows the sloping ground, and kebony cladding continues the timber language of the main house, itself a recent addition to a 19th-century villa.

To protect the surrounding trees, we developed a system of structural mini-piles and set generous offsets from each trunk, giving the roots room to grow. Securing planning in the Hampstead Conservation Area meant detailed coordination with ecology and tree specialists. Completed in 2021, the two structures add around 40 square metres the clients now use year-round.