Back To Newsroom
Installing the Iconic Twisted Facade of the PwC Tower: A Masterpiece of Engineering and Collaboration
Commissioned by the Attacq Waterfall Investment Company and developed by Atterbury Property, the PwC Headquarters Tower is a prominent example of modern architectural innovation. At 106 metres in height, this 26-storey building is the tallest structure in the vibrant Waterfall City Development and is visible from up to 30 km away. Its distinctive, twisting form is a departure from conventional high-rise designs, but creating such a complex facade required optimised design, precise workmanship and high-performance sealing and bonding solutions.
Overcoming Complex Design and Structural Challenges
The realisation of the PwC Tower’s unique facade was a collaborative effort involving LYT Architects, Arup and facade contractor Geustyn & Horak. To bring LYT Architects' vision to life, the tower’s floors were rotated by 1.2 degrees relative to one another, creating a spiralling effect that posed significant challenges in terms of construction. These challenges were overcome through Arup’s innovative use of parametric modelling, which allowed for the precise planning and optimisation of the structure.
Spanning 20,000 square metres, the glazed facade features unitised curtain walling, an advanced system where glass panels and aluminium frames are pre-assembled into large units. This approach is favoured for high-rise buildings due to its design flexibility, visual impact, faster installation times and quality control. Notably, the PwC Tower is the first building in South Africa to feature twisted unitised curtain wall panels.
Arup customised the curtain wall units to match the tower’s intricate geometry, incorporating warped aluminium frames that accommodate the twisting effect of each floor. The unitised panels, each measuring an impressive 3740mm x 1544mm, extend from floor to floor and are structurally glazed for improved thermal efficiency, air and weather tightness and durability. This technique also reduces the risk of thermal breakage in the glass, making it a robust solution for such a high-profile project.
Precision in Facade Construction
The fabrication and assembly of the curtain wall units was carried out off-site at Geustyn & Horak’s factories in Johannesburg and Bloemfontein. Using a four-sided structural glazing technique, silicone sealant was applied to bond the glass panels to the aluminium frames without the need for mechanical fasteners. Given the large dimensions of the glass and the building’s unique geometry, the use of high-strength, high-performance sealants was essential to ensure both the structural integrity and weather resistance of the facade.
FG Trading supplied a range of specialised sealing and bonding products from Tremco CPG that were integral to the project’s success. Among these was Tremco SG200, a two-part structural silicone sealant engineered for in-plant glazing applications. Its high adhesion and tensile strength, UV stability and resistance to harsh weather conditions made it the ideal choice for securely bonding the glass panels to the aluminium frames, while also allowing the curtain wall to absorb wind forces safely.
Prefabricating the curtain wall units in a controlled factory environment provided significant benefits, including enhanced efficiency and quality control. The use of Tremco SG200 further accelerated the glazing process, as it cures uniformly within days, offering faster assembly compared to one-part silicones. Additionally, the factory setting minimised delays due to weather conditions, which are common on site.
Once the units were delivered to the project site, installation proceeded quickly and efficiently. The curtain wall units were installed from inside the building, eliminating the need for costly external access. Sealing the facade was a critical part of the process, ensuring weather protection, thermal insulation and air tightness, all of which contribute to the building’s performance and longevity. The PwC Tower was built to meet LEED Silver standards, an internationally recognised benchmark for sustainable and energy-efficient buildings.
Ensuring Weather Protection and Air Tightness
To guarantee the facade’s durability and energy efficiency, FG Trading also supplied Tremco SG556, a neutral-cure silicone weather sealant, and illbruck ME220, an EPDM-based facade membrane. Tremco SG556 was used to create air-tight, leak-free interfaces within the curtain wall system, offering exceptional mechanical resistance and long-lasting weatherproofing. Meanwhile, illbruck ME220 was applied to seal the junctions between the curtain wall and the building’s structure, ensuring overall weather tightness. The membrane’s high strength, UV resistance and flexibility allows it to accommodate movement in two directions, further enhancing the facade’s performance.
A Landmark for the Future
The successful completion of the PwC Tower facade is a remarkable achievement in modern construction, demonstrating what is possible through innovative design, careful coordination and advanced fabrication techniques. Its bold, twisted facade not only introduces an iconic landmark to the Midrand skyline but also enhances the functionality of the building for the 3,500 PwC employees it is designed to accommodate. Incorporating high-performance sealing and bonding solutions from FG Trading in partnership with Tremco CPG, the facade is built for longevity, meeting stringent energy efficiency and performance standards while ensuring durability and aesthetic excellence.
Source: FG Trading, September 2024
