FAADE CASE STUDY | PADDINGTON SQUARE General view, with glazed canopies and scenic lift Glazed canopy detailing A multidisciplinary and integrated approach led the project to deliver the architectural intent and buildings high performance standards Pavilion building faade visual mock-up and CNC travertine fin prior to surface filling The travertine was visually selected for compliance with the approved lower and upper limits, and consistency, including surface irregularities. The travertine slabs were sized to accommodate the wind loads, and tested to withstand impact loads and freeze-thaw cycles. A number of glazed canopies provide shelter to users below. They typically consist of a saw-tooth glass panel arrangement supported onto the primary steel structure. A complex network of gutters and drainage channels discharges rainwater via downpipes located within the external columns. Two scenic lifts are situated at street level, taking visitors directly to the rooftop restaurant and terrace on Levels 17 and 18. The scenic lift is a 70m-high glazed structure, consisting of exposed steelwork 34 February 2023 www.cibsejournal.com erected to very tight tolerances and doubleheight glazing panels 2.4m wide and 5.2m high. These are fitted into bespoke minimalistic mullions restrained back to the primary steel structure. Minimising embodied carbon A multidisciplinary and integrated approach from early design stages led the project to deliver the architectural intent and buildings high performance standards in the most sustainable and efficient way possible. The ventilated cavity faade construction with integrated BMS-controlled blinds, combined with external brise soleil, limit the amount of solar energy penetrating the faade, thereby reducing the buildings cooling loads. The adaptive faade meant lower levels of coatings could be applied. By carrying out dynamic analysis of the cavity faade, the cavity temperature is maintained within thermal stress limits of annealed glass. As a result, the team was able to avoid the use of heat-treated glass, which minimised embodied carbon, achieving a flat-glass appearance and enabling greater transparency and colour neutrality. The use of a slender Vierendeel-type aluminium frame to achieve a transparent and light faade has led to a high-performing framing system from an operational energy and embodied carbon perspective. Thanks to the innovative design and specificaiton Paddington Square outperforms average office buildings with double-skin facades both in terms of operation and embodied energy.CJ OVI MAZAREANU is associate director project management (construction) at Mace, MICHELE SAUCHELLI is technical director at WSP and SERENA GUGLIOTTA is senior faade engineer at WSP