Eco membrane.

Like some strange alien excrescence clinging to the walls, this extraordinary transparent membrane innovatively transforms an industrial storage hall to provide new office space for a division of Siemens.

The Deckelhalle in Munich was originally built between 1936 and 1938 as an industrial storage hall. Not much more than a basic steel and glass shed of no great historical worth, it was rehabilitated in 1997 as a design studio for the Trade Fair and Design arm of Siemens by Thomas Herzog.

When Siemens decided to rehouse their 60 strong design team in an open plan workroom with conference spaces, reception, cafe and staff lounge, they were seeking a functional and practical solution with climate-modifying, power and communication services, and maximum natural light for drawing work. They were also seeking a proposal that would be energy saving and ecologically enlightened, but with a progressive corporate image.

The 1400 sq m Deckelhalle, with no insulation, cast-iron window frames and single glazing, too deep in plan for daylight to reach the centre of the floor and equipped with only basic heating was the exact opposite. There were also building constraints. The exterior appearance had to be left unaltered in order to retain the existing assembly of buildings and, internally, the original steel frame and windows had to remain visible. The basic premise however, that recycling of redundant industrial structures is an environmentally friendly act, saving on demolition waste, rubbish disposal, new building materials and expenditure of energy, has resulted in an innovative architectural solution.

The original skin, which provides adequate weatherproof shelter, has been left untouched apart from the insertion of a glass roof-light strip, and ventilation louvres at the pitch and under the eaves. Internally, up to a height of 2.5m, a new glass and timber screen with openable sections for natural ventilation, backs up the existing external band of glazing at eye level, and a 400mm thick double floor has been laid with insulation and electricity cables and ducts to service each work place. The unusual feature is a translucent membrane (K-value 1.8 W/m2/deg K), hanging from the steel rafters on guy cables between the new window lintels and the roof pitch. Air trapped between membrane and structure provides insulation and the tent-like curtaining reduces the volume of inhabited space which needs to be heated in winter, while still allowing the structure to be seen behind the recyclable and biodegradable membrane.

Apart from the energy-saving and environmental considerations demonstrated in this solution, Herzog has also reinterpreted the historical principles of transparency. While working in their new studio, Siemens designers will have a constant visual reminder of both past and future building technologies.