Detailed design and manufacture of the façade construction for PCE Ltd’s hyTower® offsite engineered HybriDfMA solution for property developer Regal London’s 14 storey Aparthotel in Whitechapel, London, progresses.
One of the key architectural requirements for this project is the aesthetics of the structural façade, allowing the new structure to be in keeping with the surrounding area encouraging a seamless transition between old and new. The image at the top of the page shows the completed sandwich panel being moved to storage ready for glazing installation. The façade consists of a series of offsite manufactured brick faced precast concrete sandwich panels which have been designed to not only provide the structural performance but also to achieve the acoustic, thermal and fire performance requirements for the building. Each sandwich panel consist of two leaves of concrete, one of which forms the external architectural face, whilst the internal leaf takes the structural loads required. Separating both leaves is a thickness of insulation, with the external leaf being tied to the internal using a fibre composite tie system which passes through the insulation. Being carbon fibre, the requisite tie strength is achieved to make the two outer leaves and the insulation one structural component, without causing thermal cold bridging. The insulation provided is European Class A1+ fire rated ensuring that the façade solution is non-combustible whilst also meeting the thermal performance requirements. To achieve the aesthetic appearance necessary brick slips have been cast into the external leaf concrete face and the joints are pre-pointed to replicate a traditional brickwork façade with all the quality and programme benefits associated with offsite manufacture.
The flexibility of PCE’s ‘kit of parts’ approach has enabled the vertical joints between components to be strategically placed in the deep window returns which will minimise the visibility of joint lines in keeping with the theme of the surrounding area. Horizontal joints are hidden in the reconstituted stone fenestrations, set back in the ribbed pattern to create a seamless appearance. Where elevations adjacent to neighbouring buildings are without windows, areas of the façade have been recessed to create texture to the façade. Offsite manufacture of the façade enables the windows to be preinstalled and sealed in the sandwich panel production factory prior to delivery to site which gives better quality control and reduction in waste during production. Erection of the units on site dramatically reduces working at height safety risks negating the requirement for any façade external access during construction. Once constructed, the sandwich panels provide a weathertight façade enabling earlier commencement of internal trades than traditional methods, leading to an overall reduction in onsite construction periods.