How textile architecture is enriching facades and roofs

Building with textiles has a long history: The idea of combining fabrics or leather with load-bearing elements comes from tent construction, which was especially important for nomadic peoples. They benefited from the shelters’ lightweight yet robust construction and their ease of transportation. In the past, wood, cables and natural materials were mainly used to stretch the material. Today they are replaced in most cases with very lightweight steel constructions, complex tensioning structures and high-tech fabrics.

The new take on textile architecture picks up on the advantages of earlier structures, adding cutting-edge engineering with sophisticated design. Tensile structures give many buildings a futuristic, modern and highly artistic appearance. While they were previously used for temporary installations, now they appear in permanent buildings – because they’re not just visually stunning, but considered weather-resistant and sustainable, too.

The fundamental difference between textile architecture and other forms of construction is that it uses tension instead of compression. It can be subdivided into three types:

• Membrane-tensioned structures: Also known as tensile fabric structures, these constructions are based on tension. They employ pre-tensioned membranes that are subject to tensile forces in all directions even in an unloaded state. A well-known example is Munich’s Allianz Arena, which has an exterior made of an ETFE membrane.
• Pneumatic structures: Air pressure plays a crucial role in these constructions. Here the tensioned textile fabric is primarily supported by the difference in pressure between the air outside and inside the structure. The Fuji Pavilion at Expo ’70 in Osaka is one example of a pneumatic structure.
• Cable-net/mesh-tensioned structures: While steel cables may be used here, from the perspective of statics, they behave like a mesh; hence, they often go by the name “mesh-tensioned”. Examples include the Millennium Dome in London and the Olympic Park in Munich.

With membrane structures and similar constructions, everything stands or falls depending on three factors: Are the tensile forces correctly positioned? Is the mounting process suitable for the material? And has the right high-performance material been chosen? The following materials are used particularly often in tensile architecture:

• ETFE films (made from ethylene tetrafluoroethylene): These films are primarily utilised in canopies and buildings, for example in greenhouses. They are considered the equivalent of glass – depending on their characteristics, they can be even more transparent with up to 95% light transmittance.
• PVC-coated polyester: an all-rounder. Thanks to its high material strength, resistance and light transmittance, it is often used in trade fair construction and temporary installations. But it can also be found in facades or roofs – for example in the cupola of the Gasometer in Berlin. It is also very cost-efficient.
• PTFE-coated glass cloth: This material can’t be gathered up or folded – which is why it is mainly employed in permanent structures and less often in temporary installations.
• Silicone-coated glass cloth: a more flexible and malleable alternative to the PTFE-coated version. The silicone coating provides good UV protection, and small tears don’t extend through the entire cloth. It is an option for both temporary installations and lightweight constructions with folding roofs.

Reasons for using high-tech fabrics can be put forward on two levels: On the one hand, there is the design aspect, and on the other, their functional benefits.

High-tech fabrics impress visually with their lightness, which is due to the thinness of the material and its transparency. These textiles, but in particular the ETFE films mentioned above, allow lots of natural light to penetrate. They are therefore a popular choice for large greenhouses, but also for the construction of swimming pools and other sports facilities.

As numerous installations in venues such as museum grounds demonstrate, textiles behave dynamically and are ideal for creating organic or sculptural forms. For these kinds of temporary structures, PVC-coated polyester is a popular option because it is both easy to work and cost-efficient. It also provides an exciting projection surface for light installations and influences the spatial acoustics .

At least as important as the visual aspect are the functional benefits:

• Membranes are extremely hard-wearing. The force applied to them is evenly distributed in all directions.
• High-tech fabrics are weather-resistant and can withstand even large wind loads if they are properly tensioned.
• They are easier to replace than materials that have been permanently built into the structure.
• Their low weight is a clear plus when spanning large areas. If the canopy or facade elements are extremely lightweight, this also influences the choice of the load-bearing material.

One of the best-known architects specialising in cable-net and membrane structures was Frei Otto. He designed the Japanese Pavilion at Expo 2000 in Hanover and was involved in the design of the Olympic arena in Munich. The sports venue’s tent roof drew on his design for the German Pavilion at Expo ’67 in Montreal and appears airy, bright and light.

Another example of textile architecture is the Gasometer in Berlin. A lightweight textile membrane on the cupola of the roughly 80-metre-high, listed monument turns it into a pneumatic structure.

The Water Cube in Beijing is a breathtaking spectacle when it is illuminated in different colours at night. The facade consists of an ETFE film that weighs just 1% of the equivalent quantity of glass. This means that not only can the construction store solar energy, but also that the interior can be illuminated with natural light – which reduces the electricity costs.

Textile architecture demands considerable specific expertise and therefore isn’t part of the standard portfolio for an architects’ practice. But it does follow a clear trend of recent years and one sure to continue in the future: sustainability. Depending on the material, tensile structures can be partially or even completely recycled. Producing the membranes often requires smaller quantities of resources than is needed to manufacture glass or concrete, for example. Their low weight opens up a wider choice of materials for the supporting structure, and crucially, smaller quantities of this material are required – meaning that resources can be conserved here, too. The materials currently in use have already proven to be robust, weather-resistant and lightweight.

And by the way: Hemp is experiencing a similar renaissance. The plant’s fibres can be used in diverse ways, and it is relatively easy to grow – find out more about the benefits of this material and the products that can be produced from it.

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