Once a boiler shop in Chathams old dockyards, the grade two listed Chatham Maritime Shopping Centre not only houses a stunning tensile fabric roof canopy, but marks an important moment in the development of tensile membrane roof structures. The original shipyard buildings have been restored to create a retail mall which is augmented by a new building that features a 60m long arch supporting a tensile fabric roof.

The addition of a fabric roof was a brave move for the site developers considering its listed status. However, this proved to be less of a hindrance and more of a help, as local planners and English Heritage declared that any extension had to stand comparable with the innovative engineering of the 19th century building that stood next to it the Boiler Shop.

Designers at English Heritage were striving for a building with striking modern features to contrast with the classic style of the Victorian engineering. The tensile fabric structure proposed clearly fitted the brief, and it was felt that a white, sail-like structure would reflect the area’s nautical history.

The first obstacle came early on, when it was highlighted that the structure had to be comply with thermal performance requirements specified in building regulations. Muir was aware that Architen Landrell had been researching insulated roofs for a number of years, so we were called in as experts in the field.

Architen Landrell was keen to put its theories concerning this into practice and introduced a revolutionary new thermal sandwich system incorporating three layers: an outer membrane made from PVC, an insulated membrane using Isowool insulation, air pockets and aluminium foil, and a lighter inner layer to provide a smooth lining. The only drawback to this scheme was the opaque nature of the fabric membrane, so to let the natural light through to the food court below Architen incorporated skylights into the steel arch forming the spine of the building.

The project led to significant advances in patterning and panel joining technology and emphasises the ability to insulate membrane roofs successfully. The development of the system has created a significant stir in the UK construction world as it has the potential to expand dramatically the number of applications for tensile membrane roofs.

As a landmark structure and as a starting point for the development of thermally insulated tensile roofing, Chatham Maritime is one of the countrys most notable shopping centres.