Featherstone Young has completed the renovation of Jack Windmill, a unique building complex which brings together a converted 19th century mill house and granary on the site of two well-loved West Sussex landmarks, Jack and Jill Windmills.

The architectural works – a five year process of unraveling the historical layering of this local landmark and its adjoining buildings – include the redevelopment of the property built onto the mill house in the 1960s and the adjoining 19th century granary into a seven bedroom house, as well as the restoration of Grade II* listed Jack Mill, which dates from 1866.

The design is radical whilst responsive to its sensitive location. It modernises the original property with a contemporary punched aluminium façade in seed-scatter pattern, whilst sympathetically restoring Jack Windmill to the same standard as its twin Jill, the older of the two mills, which was restored by a local campaigning group in the 1980s. Jack Windmill has had its five-storey timber cap restored, and when its sweeps are reinstated the pair’s iconic silhouette on the ridge of the South Downs National Park will be preserved, securing the future of this prominent local landmark.

The design follows the traditional black and white vernacular of Sussex mills, where white represents dynamic motion and black is static. The external envelope of the house is clad in black and white boarding, while the more massive elements of the granary in black-stained timber synchronise with the black mill tower of Jack Windmill (whose rotating cap is white, as is Jill, who rotates on her base).

The pop-ups are treated as dynamic structures and are clad in a reflective, mill-finished aluminium – which will weather and age to a powdery white colour. The metal panels take a cue from the agricultural buildings in the locale – and the wind-facing side of Jack Mill and the old granary – which were clad in metal to protect them from strong winds. The cladding reflects the movement of the sky, allowing them to recede into the landscape, and the perforations in the panels (based on patterns of grain blown by wind) add to their kinetic quality.

Although now within private ownership, the granary continues to host public tours on certain dates of the year, and its interior has been designed along principles of what the practice calls ‘baggy space’ – a larger, flexible central space around which more specific functions are catered for.