We take a look at two projects that have employed concrete to serve up outstanding and unusual looks
Words by Francis Pearce
New wave concrete
The undulating cast-concrete roof of the Bosjes Chapel, part of a historic Cape Dutch Farm an hour’s drive from Cape Town in South Africa, casts an array of shadows on the highly polished terrazzo floors of its rectangular, open-plan assembly space.
The building is on a landscaped plinth that elevates it above flat ground to create a focal point within the valley and make it appear to float above a reflective pond.
The shotcrete roof supports itself where each undulation meets the ground. Its sculptural form emulates surrounding mountain ranges and references the Cape Dutch gables that dot the rural landscape of the Western Cape; and where each wave of the roof rises to a peak, an expanse of glazing is joined by a crucifix. As the glass walls never meet the roof at the same angle, each connection was individually designed. These glazed elements are orientated to limit solar gain. The roof overhangs to provide additional solar shading and a covered entrance.
The curvy roof of the Bosjes Chapel is in shotcrete
The design process called for the use of 3D CAD models and a 1:2 scale physical model. On site, the formwork was assembled from 584 prefabricated timber trusses. Four hidden reinforced concrete buttresses provide stability to the ‘floating’ structure.
The roof and floor structures are completely separated by a service channel to allow for thermal movement. It contains the air-conditioning ducts, louvres and electrical reticulation located around the perimeter of the floor. Keeping the assembly space pure, the basement accommodates the HVAC system, electrical boards, pumps and filters for water features and store rooms for the chapel benches.
The 420 sq m chapel is part of a masterplan for a resort that includes newly landscaped gardens, a restaurant and a renovated guest house on a 185 ha vineyard. Steyn Studio worked with TV3 Architects and Town Planners.
Bigging it up
Neri&HU Design and Research Office designed the HUB mixed-use development in Hongqiao District of Shanghai for Shui On Land, with the Performance and Exhibition Center at its heart. Using a large-scale mash-up of surface materials, the performance centre’s interior is conceived as a solid rock out into which programmatic elements are inserted.
Spaces are carved out and programmatic elements are inserted into the sandstone, such as bars in the form of wooden houses; halls of mirrors in black-glazed tiles; bronze elevator cabs and private rooms dressed in hand-painted tiles. A floating canopy of wood sticks hovering over the three-story atrium transforms the space into a forest. Gallery openings are wrapped in interlocking solid sandstone and light walnut balustrades.