Building with Fabric – Material Choices

Today’s architect has a difficult decision to make when it comes to choosing materials. There is steel, glass, concrete and wood. What about the fabric! Architectural fabric structures are rapidly becoming a very common and visible part of the built environment. No longer used for garden parties or traveling circuses, these structures come in many new forms and uses.

Fabric structures for as few as one person, such as at a boutique hotel in the Australian outback, are being designed to cover more than 50,000 at the Super Bowl in Houston, Texas. Fabric structures are now also being designed to cover animals, such as at Seaworld, Orlando, where these structures cover the dolphins to prevent them from getting sunburned (do they get sunburned too?). And let’s not forget man’s new best friend, the automobile. Increasingly, the car is taking center stage where valet attendants, airport parking owners and car dealers are discovering the benefits of covering cars.

Fabric structures are used as ceilings, sails, walls, lights, shades, and even signs. With all these different uses and forms, there are a variety of materials to choose from depending on one’s needs, budget and design.

The best way to determine which material to use is to see what has already been used for the type of building you are considering.

If you are interested in structures such as tents or umbrellas where the main purpose is to provide temporary nomadic shelter, you are probably looking for coated polyester or vinyl laminate.

If you’re researching awnings and canopies, the options are endless. You will most likely hear words like acrylic canvas and backlit fabrics and materials that you can apply graphics to.

If shade is your primary concern, the buzzword is structural mesh, high-density polyethylene (HDPE), perforations, and light transmission percentage.

For storage, industrial applications, and temporary buildings, a common term may be clear or fabric buildings pre-engineered with materials that are resistant to mold and mildew, such as polyolefin.

The interior and lighting industry has its own variety of fabrics where flame resistance, UL ratings and reflectance percentage are the most important aspects.

Air and tension fabric structures are highly dependent on the structural characteristics of the fabric, so tensile strength, sound absorption, and solar transmission play important roles in their selection.

So what material do you use?

Is your project near water? Is it meant to last 20 years? Do you want to see it from afar or do you want it to be dark inside at noon? These are all important questions that one must answer before even starting. Fabric structures have very few components. In most cases, it’s just steel, fabric, cables, and hardware. The choice of each component will undoubtedly affect the others. Other topics include: span, size, availability, cost, codes, etc.

In most states, totally enclosed, permanent structures require a “noncombustible” or Class A/B rating according to building codes. The most recognized and accepted material used for architectural applications is Teflon or PTFE coated fiberglass.

Well-known manufacturers include Saint Gobain, Verseidag, FiberTech, and Taconic. Teflon comes to the site brown like a pair of khaki pants, but bleaches to a milky white over time (usually 4-8 weeks). The biggest problem with Teflon is that it is stiff and brittle and must be handled very carefully to avoid breaking the fibers. The best part is its shelf life (25+ years) and “self-cleaning” attributes.

Other “non-combustible” materials include silicone-coated fiberglass, Gore Brand Tenara architectural fabrics, and ethylene tetra ethylene, or ETFE.

Silicon has been on the market for quite some time. Unlike Teflon-coated fiberglass, which can be heat-welded, silicon must be glued together with a special adhesive. Silicon’s advantage over Teflon is its translucency, cost, and color availability. Gore Brand Tenara is also in the “non-combustible” category. Its advantages include its high translucency, long shelf life, and it is more flexible than silicon or Teflon, so it can be used for shrinkable structures.

ETFE is not really a fabric, but rather a film that is currently being promoted as an alternative to structural glass. It is “green” and is the new trendy material for architects all over the world today. It is being used in FIFA stadiums in Germany, the Olympics in China, specified for commercial and retail buildings and option to create artificial rainforests for zoos and science centers.

Most of the fabric structures being considered today are for uses that do not require full enclosure. That means they are most likely “outdoors” or do not require a Class A rating. Class C is the most common rating and NFPA 701 is the most widely accepted certification by most fire marshals. Vinyl-Coated Polyester (PVC) is the most common material used on the market today.

What’s not to like. The material comes in a variety of colors, strengths, weights, thicknesses, perforations, translucency, and textures. The material is flexible and stretches quite well. You can find material with guarantees of 10, 12 and up to 15 years. You can find material from 50 to 100″ wide so you can have few, fewer, or the fewest number of seams.

Manufacturers include Ferrari, Mehler, Naizil, Seaman, and Verseidag to name a few. These are the names most seen in the Specifications, which means that these companies directly market and help the Architect in the early stages of the design.

PVC comes in a variety of superior finishes: acrylic, PVDF, and PVF film. There is a lot of debate about top finishes, but all manufacturers agree that they are necessary to protect the base fabric from UV, water and wind degradation. Frankly, it’s about the liners. PVF is a film that is applied to the main fabric, while acrylic and PVDF are coatings. Both PVF and PVDF claim to be “self-cleaning” or provide the base material with a much cleaner, maintenance-free surface, but both require additional shop work that may be unknown to the Architect. Both PVF and top-of-the-line PVDF require the top layer or film where two panels meet to be ground so that they are RF welded. This requires a lot of time and a lot of care to keep the seams free of dirt, pattern and mildew. There is “weldable” PVDF, but its warranties are not as long as high-tech topcoats. PVC structures love graphics and provide a great backdrop for projected images.

Today, more and more fabric structures are designed for shade only. Structural meshes and perforated fabrics are specified by the need for shade, the need to allow elements to pass through the material, and the need for a space to “see through and be seen”. The most commonly used material is high-density polyethylene (HDPE). Manufacturers include Multiknit, Coolaroo, and Shadetex. This material is a higher grade mesh than what you would see at a home improvement store or outdoor furniture store. HDPE is used for playgrounds, areas requiring hail protection, schools, day care centers, as well as theme parks and public gathering spaces. The mesh is warm so you can stay cool. The mesh comes in colors, with a fire resistance rating and with different perforations. It has a useful life of 8-10 years and in most cases reduces the size and loads on the structural system and foundation because it needs less wind.

If you want to keep it simple, then work with materials that don’t rely on their structural characteristics for stability. These materials are usually encased in a frame. Materials are typically vinyl-laminated polyester, acrylic-coated canvas, and lightweight topcoat materials. Sunbrella is a common brand. The material has less technical information available to apply to fully designed lightweight structures, but when used as a cladding in a frame it offers many opportunities to the architect. You can apply graphics to the material, add texture to the surface, or do something really unique.

If you want to look for materials for interior applications, look no further than the industrial fabrics and theatrical drapery industry. There are lightweight PTFE materials used for domed stadium roofs, PVC fabrics are used for the interior stretch-fabric sculptures, while theatrical drapery materials from companies like Rosebrand and Dazian are used for a smoother appearance. Spandex/Lycra is another common material used to transform temporary and permanent spaces, but it requires the material to be fire-treated prior to fabrication.

Finally, it is worth dreaming about the future of architectural fabrics. The wish list would include “smart” fabrics, fabrics that change color based on weather, light, or mood. Fabrics made with optical and photovoltaic fibers, materials with a longer useful life, greater tensile strength, improved self-cleaning, greater translucency and respectful of the environment.

The future of Architectural Fabric Structures depends on the continued effort of manufacturers to improve their existing products and introduce new materials.