Awnings & canopies
Fabric Architecture | Sourcebook 2009
For decades the choice of awning and canopy fabric was limited to cotton canvas. While cotton offers a great look and feel, it has performance limitations outdoors. Although traditional cotton duck, or canvas, is still used occasionally — especially when specifiers desire a traditional look — synthetics now dominate the market for residential and commercial awnings and canopies.
Thanks to technological breakthroughs in synthetic fabrics — and in topcoatings to protect those fabrics — progress continued with increasing acceleration. During the 1980s, it was not uncommon to answer the question of awning fabric performance with a question mark — or at least a disclaimer. Warranties, guarantees, colorfastness, ultraviolet stability and even tensile strength were in their infancy then.
Material advances have been fueled in part by improved synthetic yarns as the basis — the scrim or substrate — for many laminated fabrics, giving them greater strength and flexibility. Coated fabrics made of polyester fibers improve the blend between cotton and polyester, allowing mills to produce a clean, strong and smooth product.
Woven polyester fibers also have evolved, with substrates that have anti-wicking properties. Yarns are treated in the spinning process to resist capillary-like moisture absorption, which helps keep dirt and moisture out of the scrim, allowing them to resist mildew.
The chemicals for fire resistance, ultraviolet stabilization and pigments have improved too. And air-jet looms produce woven fabrics like acrylic more consistently, with fewer anomalies and in updated styles and weave patterns. Such performance improvements extend the products’ life expectancies.
Fabric choice for an awning or canopy depends on the application:
- interior or exterior
- illuminated (backlit) or standard commercial/residential project
Fabrics used in illuminated awnings and canopies, for instance, differ from other awning fabrics greatly in translucency and slightly in weight. Fabrics designed for illuminated awnings, such as vinyl-coated and vinyl-laminated polyesters, typically are specified to maximize light translucency.
Graphics also are a consideration. Heat-transfer films, heat-sealed inset fabric, sewn-in inset fabric, eradication, pressure-sensitive vinyl, silkscreening and hand painting are often used to decorate awning fabrics. Not all methods work well with all fabrics, so doublecheck fabric compatibility if you want to use a particular graphic method.
Handling also varies among fabrics. Look into whether the fabrics can be heat sealed (with or without seam tape) or sewn, their shrinkage and stretch factors, and whether cleaning agents, spec sheets and technical manuals are available.
According to the Awning Division of the Industrial Fabrics Association International (IFAI), seven primary fabrics are used in awnings and canopies:
- vinyl-laminated polyester
- vinyl-coated polyester
- acrylic-coated polyester
- vinyl-coated polyester/cotton
- solution-dyed acrylic
- painted polyester/cotton
- solution-dyed modacrylic
Most awning fabrics weigh between 9 and 17 ounces per square yard, although the range varies according to fabric type. All seven types have good abrasion resistance and will last between five to eight years, depending on climate and proper fabric care.
Coatings, laminates and topcoatings are commonly used to equip fabrics with protective qualities. Coatings are liquids that are cured as they are applied onto the woven scrim, which is the fabric base. While the coating is in liquid form, chemical compounds are added to provide pigment, flame retardance, and UV, water and mildew resistance.
Laminates offer the benefits of two or more materials in one. Technically, they are formed when a reinforcing scrim, or base fabric, is calendared between two layers of thermoplastic film. Generally they are manufactured not only by applying heat and pressure, but also through inclusion of an adhesive layer between the film and scrim layers.
Some vinyl-laminated polyesters, fabricated specifically for backlighting, are highly trans-lucent. Those meant for standard usage are translucent depending on their color. These fabrics weigh between 10 and 16 ounces, are resistant to UV light, mildew, and water and are recommended for use in areas of sustained high humidity.
Primarily used for illuminated awnings, with the degree of its translucence depending on its color, vinyl-coated polyester weighs 11 to 17 ounces and is resistant to UV light, mildew and water.
Coated with acrylic rather than vinyl, this fabric is translucent depending on its color, weighs 9.5 to 12.5 ounces, and is resistant to UV light, mildew and water.
Typically weighing about 15 ounces, vinyl-coated polyester/cotton is resistant to UV light, mildew, and water. Because of their cotton base, these opaque fabrics are not recommended for use in areas of constant high humidity.
Like vinyl-coated polyester/cotton, painted polyester/cotton is opaque and is not recommended for areas with constant high humidity, because of its cotton base. A weight of 11 ounces is typical. The fabric is resistant to UV light, mildew and water.
Solution-dyed acrylic was introduced for awnings in the early 1960s. Acrylic is actually a generic name for different mixtures of a chemical compound of acrylonitrile and other elements. To be called “acrylic,” a fiber must be composed of at least 85% acrylonitrile. The other 15% often consists of various additives, such as chemicals that provide UV resistance.
Acrylic generally is considered an upscale material. Offering a soft hand and vibrant colors, the fabric is often marketed toward customers who want to coordinate their awnings, casual furniture and interiors. Acrylic offers the aesthetics of cotton but is resistant to UV light, mildew and water. Weaving makes it highly breathable, so hot air and moisture will not be trapped.
In solution dyeing, color pigments are added to the acrylic fibers while the fibers are in a semiliquid state. As a result, the color becomes an integral part of the fiber and, unlike piece-dyed acrylic, won’t wash out. Solution dyeing reduces fading and deterioration due to UV exposure. Solution-dyed acrylic is translucent, depending on the color; typically weighs 9.5 ounces; experiences some shrinkage in cold weather, some stretch in hot weather.
Modacrylic refers to a fiber composed of between 35% and 85% acrylonitrile. Although modacrylic shares many of acrylic’s characteristics, it has significant differences, including increased flame resistance and heat sensitivity. Solution-dyed modacrylic is translucent, depending on the color, typically weighs 9.25 ounces and is resistant to UV light, mildew and water.
Fabrics can be finished further with a clear topcoating for added durability and cleanability. Acrylic was the first topcoat to be used widely, followed by urethane. Since then, two clear fluorocarbon films, PVF (polyvinyl fluoride, also known by its brand name, Tedlar®) and PVDF (polyvinylidene fluoride) have come into use. Strong evidence indicates these topcoats keep vinyl laminates vibrant longer. Coating and topcoating compounds often are credited with helping extend the lifespan of fabrics into the five-year range. But they’ve also been criticized for their stiffness (especially PVF) and sometimes erratic quality. Still, topcoating use continues to grow.
A topcoating, which is an additional layer of protection applied to either coated or laminated fabrics, is typically a film that is laminated into place, usually only on the fabric’s exposed or “top” side. Topcoats prevent plasticizer migration and enhance graphics and cleanability. The fluorocarbon films generally increase the fabric’s cost more than acrylic and urethane topcoats.
PVF film, developed for residential siding in the 1960s, was applied as a topcoating to awnings and flexible signs in the 1980s. It comes with 15 standard colors integrated into the film, with customizing available, even regarding the level of gloss.
A transparent PVF allows graphics and lettering to show through. The film is practically impervious to pollutants, repels dirt and resists sunlight deterioration. As an awning topcoat, the film must be no less than 1 mil thick for sufficient strength.
PVDF, developed in the mid-1980s, does not require an adhesive, only heat and pressure, to be laminated to a fabric.
In recent years, the chemical solvents used in the industry have come under strict environmental regulations. Strides have been made in cleaning solutions, but the industry needs to develop more environmentally friendly water-based solutions. The situation has led to ongoing research and should affect future coating and laminating developments.
Solar shading materials, which reduce glare and heat gain, are beneficial for skylights, solariums, greenhouses and buildings with any large glassed portions. The type of application, exterior or interior, and the type of fabric used vary depending on climate and personal needs. Exterior coverings primarily bounce sun rays off the fabric. They are more efficient, but more expensive, than interior coverings. Interior methods offer a range of fabric shading and openness percentages to afford the desired amount of sun and light control.
In short, the tighter the fabric weave — with 5%-open fabric generally the tightest weave available on the market — the less the sun and heat penetration into a room. Such fabrics are typically designed for use in standard shading applications: roll-up shades, Roman shades, folding shades, pleated drapes, vertical blinds, drapes, sheers and screens, among others.
Unlike metal screens that come in limited colors, fabric screening is available in many colors to match interior or exterior décor. Sunscreens maintain an acceptable level of brightness and allow an unobstructed view of the world outside. Sunscreening, whether fixed or movable, also can cut heat loss by as much as 15% with single-pane glass. When windows need cleaning, the fabric sun guards can be rolled out of the way; cleaning the fabric itself is a simple soap-and-water operation.
Woven fiberglass comes in many colors, for both interior or outdoor use. It is rot-proof and antibacterial, keeping out 85% of solar heat without interfering with visibility. Woven fiberglass can block as much as 70% of the sun’s rays. The coating can be textured, and the weave may be varied to increase opacity.
Vinyl-coated polyester can block up to 80 percent of the sun’s rays.
Metals, such as woven bronze strips or louver-stamped aluminum, can block more than 80% of solar heat gain, but generally come in a limited number of neutral colors.
Knitted fabrics, such as monofilament polyethelene, originally designed for agricultural crop protection, can be used for tension structures that provide solar shading. Shadecloth can be manufactured in a variety of colors, offers stretch and resiliency and remains flexible under a range of conditions without tensile-strength loss. Light transmission can vary from 20% to 90% shade factor; UV filter construction can range from 30% to 70%.
Window film is composed of a microthin laminate of polyester and metallized coating bonded by adhesives. The film provides solar insulation for all types of glass. Generally, the film is coated with a durable scratch-resistant covering and carries a multiyear manufacturer’s warranty. Window films are designed to reflect and absorb heat, control light transmission, reduce heat transfer through windows, absorb ultraviolet radiation or some combination of these characteristics.
As outdoor living space becomes increasingly prominent in homes and commercial areas, casual furniture fabric selection has grown, offering opportunity for color and texture coordination among awnings, casual furniture and umbrellas. Of the many solids, stripes and patterns available, some patterns are woven using jacquard and dobby techniques or special surface effects, such as linens, twills and sateens. Custom patterns also are available.
Furniture-weight versions joined the solution-dyed acrylics in the early 1980s. By the early 1990s, acrylics led the market, followed by printed polyester, PVC/acrylic blends, printed PVC, PVC/olefin blends, cotton, vinyl and olefin.
Technical advances in pigments used to print acrylic fabrics have helped improve its performance. UV blockers have been added to improve color longevity.
Improved pigments have increased the popularity of printed polyester fabrics in the middle price range. Printed polyester offers excellent strength and good UV resistance, but it does not offer the life or performance of solution-dyed acrylics or olefin.
Vinyl and PVC-coated polyester
Although vinyl and PVC technically are the same thing, in the casual furniture industry, they are distinguished by manufacturing technique. Vinyl is a sheet product that traditionally has been available in white, yellow and green.
PVC typically is an open-weave, PVC-coated polyester that performs well outdoors, dries quickly and is more comfortable than vinyl. It also offers a broader and more sophisticated color and pattern selection. PVC offers excellent colorfastness and strength. A closed weave provides increased UV protection for use in umbrellas.
Olefin, one of the newest casual-furniture fabrics, is designed for the middle and upper markets. It feels similar to traditional fabrics, dries quickly and has good colorfastness, although it does not have the hand or UV life of acrylic. It resists abrasion, stains and UV degradation.
Blends of various fiber compositions
An increasing number of blends — PVC/acrylic and PVC/olefin, for example — also are available, offering attractive pricing and performance options.