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Bernard Weatherill House, Croydon

  • Croydon

  • 2013

  • Contractor Sir Robert Mc Alpine

  • Photos: Charlotte Wood Photography

Office Building - BREEAM Excellent rating

The Croydon Council PSDH civic building is a modern office building for Public Administration , which acts as a catalyst for the redevelopment of the entire surrounding neighbourhood , providing a strong sense of identity and presence as part of the overall revitalization of the Croydon area. The building offers a complementary juxtaposition to the Town Hall and the Clock Tower , dating back to the 17th century , which symbolize the democratic heart of this town on the outskirts of London. The development consists essentially of two buildings : the Main Building of 13 floors above ground and the Annexe Building of 5 floors with a total offices surface of approximately 20,000 m2.
The building is constructed from an in-situ concrete frame with exposed concrete soffits and chilled beams to the office floors. A fully glazed façade was chosen in direct response to the councils brief for a transparent building and one whose inner workings are visible to the public. Through the use of twin skin glazed façades, it provides high levels of natural daylight and view throughout the building. Coupled with an efficient passive solar shading solution that greatly reduces the requirements for mechanical cooling and heating, it allowed the use of highly energy efficient technology to meet with the demands of the building.

Systems

  • Double skin envelope

  • Typical elevation: SSG unitised system

  • Ground floor: grid and panel system

  • Horizontal aluminium brise soleil

  • Glazed atrium roof

The technology

The type of façade that mainly features the project is the twin skin envelope designed with innovative high quality products. The inner skin consists of a SSG unitised system. The DGU glazing is bonded with the structural silicone technology, it consists of an outer laminated pane 66.2 with high performance coating Ipasol neutral 60/33, 18mm warm edge with argon gas and an inner laminated pane 55.2 performing a glass U value of 1.1 W/m2 °C. The outer skin consists of toughened laminated extra-clear 13mm fritted glass, fixed to the hot dipped galvanized steel structure by means of countersunk AISI 316 stainless steel bolts. The twin skin 800 mm ventilated cavity has been designed to allow maintenance of the inner skin and it consists of hot dipped galvanized grid supported by cantilever brackets projecting through the plane of the façade. The access to the ventilated cavity is provided by more than 100 service doors placed in the curtain walling. The outer skin has trapezoidal overhangs that extend up to an height of 5 meters above the terraces level, where are located motorized louvers which are able to control and exhaust warm air during the summer season. The South elevation sloping façade has been designed adopting parallelogram modules to accommodate the complex geometry of the building. The performance tests carried out have demonstrated the excellent thermal and acoustic characteristics of the product: In compliance with EN 140-5:1995 airborne reduction of R'W 45 dB, in compliance with EN 20140:1992 floor flanking party of 58 dB. In addition, the thermal calculations performed shows an excellent thermal transmittance value of 1.30 W/m2 °C. The curtain walling system have been delivered on site with "just in time " deliveries, stored at relevant floor levels, from where they have been prepared for installation, which has been carried out operating completely from the inside of the building with a bottom-up installation sequence The construction process of this project involved more than one year of design, close cooperation with the architect, and the release of over 1300 construction drawings and 8000 shop drawings.

Architects

EPR Architects Ltd

EPR London based practice, have a long history in sustainable architecture having designed both the first office development in the country to use combined heat and power (CHP) technology and the first residential development to win an ‘excellent’ EcoHomes rating from the Building Research Establishment. EPR included in AJ100 Top UK Architects 2013