Architect and Builder Magazine South Africa Dec 2017 / Jan 2018 - Page 45

the Silos, the organic rounded shape of a single kernel of the corn recovered from the original building was digitally scanned and scaled up to fill the 27m high volume and then translated into thousands of coordinates, each defining a point within the silo’s tubes. Mapped out physically with nails, the concrete tubes, only 170mm thick, were then lined with inner sleeves of new reinforced concrete, essentially building a new building inside the old one. The new concrete sleeves created a stable composite structure 420mm thick and provided a cutting guide for removing portions of the old silos. The existing tubes were pared back to reveal the curved geometries of the 4,600m 3 atrium. The cut edges were polished to give a mirrored finish that contrasts with the building’s rough concrete aggregate. Each of the carved tubes was capped with a 6m diameter panel of laminated glass that brings daylight into the atrium. The glass carries a ceramic fri t pattern specially commissioned from the West African artist, El Loko. As well as mitigating heat from daylight, the frits create a safe, walkable surface for the sculpture garden at the rooftop level. The remaining internal tubes were removed to make space for the 80 Zeitz Mocaa gallery spaces providing 6,000sqm of exhibition space. Underground tunnels surrounding the atrium have also been adapted for artists to create site-specific works. The proportions of the upper half of the tower portion of the silo complex made it unsuitable for exhibition space. The design team reconceived this structure as an illuminated beacon, which now houses the Silo Hotel. Façade The exterior of the building was altered with 2 major changes. Firstly, the magnolia paint was stripped away to reveal the original concrete of the silos, with all of the character of the original construction techniques and the particular patina created by years of weathering and repairs. Secondly, the original windows were removed and replaced with larger ‘pillowed’ multifaceted windows on top of the silos. When considering how to bring light into a previously enclosed, dark space, the architects were inspired by the bulging glazed texture of a Venetian lamp. Arup followed a 24-hour lighting philosophy for the initial lighting study, developing a holistic lighting solution for the atrium space that carefully balanced and combined daylight and 45