Construction World September 2024

maximise use of the deeper spaces for the areas between corner units. Larger units are on the top three floors, with five duplex and four triplex configurations. Bedrooms not adjacent to the outer façade are lit and ventilated from small courtyards open to the roof. The triplexes have roof terraces with partial pergola covering and glazed balustrades to maximise views. Terraces are inboard, behind strategic openings in the glazed façade to provide weather protection, and to enable residents to open their sliding doors onto the terraces. Mixed uses The Rubik introduces retail uses at ground- and first-floor levels, creating a more dynamic and active street frontage with natural surveillance. The retail space on the first floor on the northern portion of the building connects to the ground floor retail area. This activates the first-floor façade, as required by the Tall Building policy of Cape Town. Colour palette and materials Natural-looking materials and a muted colour palette throughout the building create a more natural, warm feel. Sustainable elements The Rubik incorporates several sustainable design features. It is a true mixed-use development that maximises the site area and helps densify and animate the city within walking distance to workplaces, local amenities and public transport. Environmentally friendly and sustainable construction materials and techniques were used, including sustainably sourced timber and durable composite materials to ensure longevity, paints with low volatile organic compound (VOC), limiting plastering on masonry walls in the service and escape areas or on exposed reinforced concrete walls, soffits and columns. High-performance double glazing throughout, with desk-height opaque spandrels in offices to reduce solar gain and improve space efficiency. Recessed, semi-enclosed balconies promote natural ventilation and reduce wind loads. Above-ground parking facilitates natural ventilation and smoke extraction. Energy-saving electrical devices and efficient mechanical, electrical, and wet services are installed throughout. The building optimises lift usage with just five elevators, using careful destination control and dual-purpose fire-fighting lifts to maintain efficiency without compromising on waiting times or safety.  Photos: Sean Gibson

elements of the tower above into the parking podium. This approach responds to Heritage Western Cape concerns that the early design iterations of flatter translucent screens at the parking levels might negatively impact the surrounding context. Building access Access to the residential entrance is off Loop Street. Access to the commercial accommodation is off the busier Riebeek Street. Both are flanked by retail units, accessed from the corner of Riebeek and Loop. This strategy maximises street activation on the small site. Vehicle entry points are on the southern edge of the Loop Street boundary, adjacent to the heritage buildings, set as far from the Loop/Riebeek intersection as possible. The Sea Street entrance is also positioned away from the street corners on the southern boundary. To maximise street-level activity, the only services at ground floor are the municipality’s non-negotiable requirements of an electric sub-station, firefighting equipment and a small meeting room. Internal planning At only 28 m x 29 m, the constricted site area presented challenges to resolve the internal layout. The building was configured to accommodate five lifts, two escape stairs, active street level entrances, municipal services, internal vehicle circulation and parking, office floor layouts and residential units above.. The centralised lift core and scissor stair positioned on the common southern boundary accommodates the parking and spiral vehicle ramp circulation below. The WC core and lift lobby is positioned between the lift and stair core. Full height glazing flanking the scissor stair core on the common boundary maximises views of Table Mountain and the CBD. An additional challenge in the tight site area was how to provide efficient parking spaces and compliant vehicle which required careful positioning of large columns to secure City The challenge of using the full extent of a square site is having sufficient frontage for bedrooms and living spaces, while also accommodating usable space in the deeper zones inside the perimeter. On the typical floors, larger two-bedroom apartments are positioned on the two northern corners, and one-bedroom units on the southern corners. Longer bedrooms in the narrower one-bedroom flats are positioned at the rear to planning approval. Residential layout

37 CONSTRUCTION WORLD SEPTEMBER 2024