LOCAL PROJECT
The origami concept also plays out in an extraordinary-looking ceiling feature outside the entrance lobby for the building which incorporates a continuum of inverted pyramid shapes .
KEY MATERIAL CONSIDERATIONS
Brunette adds : “ It is also vital to make sure that the timber is as durable as conventional cladding materials . This has been done by adding a rain screen of timber cladding outside the CLT structural panels , which are not in themselves weatherproof and are protected by a breathable membrane .
“ The rain screen consists of Accoya , a type of board that is made from acetylated South African pine cuts , which have a long service life and are guaranteed by the supplier . They can also be replaced separately , leaving the building still enclosed by the CLT panels so that occupation is not disrupted .
GARETH GRIFFITHS IMAGING
Breakaway area , with a view from the ‘ inside ’ of the pleated façade .
these design elements have a strong engineering and design rationale backing them up , but at the same time we have managed to create beauty and joy out of them . They are key to the building ' s identity and aesthetic and create memorable experiences . These include natural light and natural timber in the case of the façade ,” he says .
According to Mahoney a major design requirement was the building having an operable façade . This is achieved via the unique pleated ( zigzag ) façade concept , which fills a vital function from the engineering perspective . He admits that inspiration for the pleated façade came in part from doing origami at his desk in the office . “ Triangles as per origami shapes take on a special meaning in this building , as borne out by the façade design and several other design elements . But ultimately the pleated façade is driven by logic : it creates a north-south orientation for the façade , meaning that you can control the effect of direct sunlight .
“ Timelessness in architecture is something that many designers strive for . The timber façade itself will evolve and keep functioning over the years , changing colour as it weathers , developing a patina , and making the building stand out as unique .”
Sean Mahoney , project architect .
“ The glazed and timber saw-tooth façade is prefabricated to enable a swift installation time and ensure a high-quality assembly . Using timber as a key component of the façade allows for the strong but light properties of this material to be taken advantage of in an innovative way , further strengthening the landmark nature of this building as prestigious corporate headquarters . Timber is ideal for prefabrication because it can be machined to very high tolerances .”
“ Using the initial parametric modelling , we were able to identify a more refined set of options to assess which combinations worked best . It was found that the zigzag façade that we adopted for level 2 and 3 performs as well as a straight deeply shaded façade .
“ In essence , orientating the glazing towards the north and south allows for a more glazed façade , without external shading devices that can obstruct views to the outside and reduce the amount of internal natural light . This design significantly reduces the amount of sunlight entering the building , which in turn means that the internal spaces can largely rely on natural ventilation and not air-conditioning to remain comfortable .”
BENEFITS OF THE TIMBER FAÇADE
1 . The timber façade forms part of a range of measures facilitating natural indoor temperature control and fresh air inside the building for most of the year , instead of conventional air-conditioning .
2 . The use of a natural material instead of brick , concrete or additional aluminium and glass in the façade has greatly reduced the Ridge ’ s as-built carbon and energy footprint by lowering its embodied carbon and energy .
3 . The structurally graded , FSC-certified engineered timber used in the production of the CLT is sourced from sustainable plantations largely located within the Western Cape . So , this material is both a net sequestrator of carbon dioxide from the atmosphere and , as sourced within the province , also minimises the transport carbon and energy considerations .
Arup ’ s engineers have calculated that 354Mt of CO 2 has been saved by using timber on this project in lieu of conventional materials ( such as brickwork ), in addition to the usage of a natural material which itself enters the lifecycle of the project with a negative embodied carbon content .
In total , 960m ² of CLT timber panels were used in cladding the building , which is the equivalent to 36 tonnes of timber . The CLT timber panels were fabricated at XLAM , a dedicated factory in Cape Town . This is at present the only CLT factory in South Africa , according to the company ’ s Jamey Smily .
www . timberiq . co . za // OCTOBER / NOVEMBER 2021 11