From its humble beginnings as a castle that was continuously extended and renovated, the residence of Augustus the Strong, Elector of Saxony and King of Poland, ultimately became one of the most iconic landmarks of the baroque city on the river Elbe. Dresden Castle suffered extensive damage during World War Two and almost met the same fate as the Berlin City Palace, which was demolished by the East German government in the 1950s. Extensive restoration work started in 1991 with the objective of transforming the entire castle into a museum and a home for art and science'. After restoration of the exterior façade, putting the dome roofing, made of ETFE foils, on top of the small inner courtyard has been one of the main priorities of this year's work. Any potential monument protection issues were eliminated during the planning stage, thanks to the flexibility and filigree structure of the membrane roofs made of ETFE foil cushions.
When the roof was completed, the courtyard became an atrium that houses the museum's central reception and an exhibition on the castle's history. The elegant, light dome structure, made of ETFE foils, is large enough - at 41 by 25 metres - to hold an entire handball court, including spectator stands and fits in seamlessly with the castle's architectural heritage. The membrane roof above the inner courtyard consists of a rigid grid of 265 rectangular profiles. These hold up the two-layer foil cushions made of ETFE.
CENO TEC GmbH from Greven, Germany was responsible for the design, construction and assembly of the ETFE foils; manufacturing the steel structure, ropes and fans; and complete installation. The two-layer foil cushions are made by company NOWOFOL Kunststoffprodukte GmbH & Co. KG. The foils are extruded from Dyneon ETFE high-performance plastic and are 250 micrometres thick. Foils made from this material have a tensile strength of up to several tonnes per square metre and only weigh between one and one-and-a-half kilograms per square metre - qualities that surely would have impressed Augustus the Strong! The foils are highly resistant to UV exposure, chemicals, solvents and all kinds of weather. They do not require the use of plasticiser or stabilisers that dry out over time and can cancel out the roof's positive characteristics. The foil's extremely smooth surface means there are no cracks in which bacteria and fungi can lodge, and a short rain shower is enough for cleaning. Multi-layer ETFE foil cushions also provide excellent acoustic and thermal insulation. As a result, it will be possible to use the foyer for "open air events" all year round.