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Awning fabric attachment methods
Lacing: The most traditional technique. Grommets are placed along the edge of the fabric cover, which then is tied to the frame by lacing thin rope through the grommets. Besides providing a traditional look, lacing allows the cover to be tightened easily if the fabric wrinkles over time. It’s not a good method for backlits, since the lacing (unless hidden in some way) can be seen through the fabric. Also, heat-sealed or sewn-in graphics will be distorted once the laced cover is stretched.
Track systems: The fabric is folded over, and a rope or plastic welt is sewn to the fold. The fold is then channeled into the frame. The advantage of this method is that the fabric is insulated from the building to which the awning is attached. It also requires less assembly time—the awning can be assembled on-site. Track systems require more sewing time, however, and the frame ridge is visible at the top of the awning.
Screws: This is a fast method of awning assembly. The cover is stretched around the frame and attached using self-tapping hexagonal screws, but it is not easily tightened or adjusted once the screws (and screw holes) are in place.
Staples: This also is a fast assembly method. The fabric is stretched over the frame, then stapled to the frame. (Because of its relative softness, aluminum works best.) As with self-tapping screws, however, this method is best used for points of attachment that won’t be seen.
Staple-in extrusions: These have similarities to stapling and track systems. The fabric is stapled into “slots” built into specially designed framing. The slots are then covered with strips of vinyl trim. The fabric need not be welded or sewn together. This method works well for PVF-coated materials and other fabrics that are difficult to sew or weld. Non-sewn attachments also can last longer. On the other hand, there are many frame lines (visible especially with backlits), and some shapes are difficult to create with extrusions.
Snaps or hook-and-loop fasteners: These are used in cases where easy access is needed to the inside of an awning or canopy. They’re also used when the awning or canopy has been placed beneath a building overhang or where light bulbs inside a backlit need frequent changing.
Fabric terminology
Denier: A weight-per-unit-length measure of any linear material. Officially, it is the number of unit weights of 0.05 grams per 450m length. It is a direct numbering system in which the lower numbers represent the finer sizes and the higher numbers the coarser sizes. In the United States, the denier system is used for numbering filament yarns (except glass), manufactured fiber staple (but not spun yarns), and tow. In most countries outside the United States, the denier system has been replaced by the tex system.
Fiber: The fundamental unit that makes up a textile raw material such as cotton, wool, etc. Fiber is now used in the broad sense to include filament yarns, monofilaments and tow.
Pigmenting: The process of applying color to fiber stock, yarn or fabric; there may or may not be thorough penetration of the colorant into the fibers or yarns.
Scrim: Open-constructed fabric used as a base material in coated and laminated fabrics.
Tow: A large group of continuous filaments, such as nylon, polyester, etc., without any definite twist.
Warp: Threads that run through the length of a roll of fabric.
Weft or filling: Threads that run in the crosswise direction of woven fabric.
Welt: A strip of material seamed to a pocket opening as a finishing and a strengthening device.
Wicking: A phenomenon that occurs when moisture accumulates at the edge of a fabric where substrate yarns may be exposed, or in sewn seams where threads come in contact with the substrate.
Fabric types
Solution-dyed acrylic: These fabrics are guaranteed to hold their variety of bright colors for five years. They can help create bright, long-term street banners.
Cotton duck, or canvas, and drill cloth: These are “natural” fabrics. They tend to last fairly well for both indoor and outdoor applications and generally are less expensive than synthetics. However, they are less UV-resistant, and some believe that they are less capable of holding a variety of bright colors.
ETFE: Ethyltetrofluoroethylene. A structural clear film or “foil” best used under pressure in the form of an air-filled pillow.
Fiberglass: A widely used base material for tensile structures. It is typically coated with silicone or PTFE for durability. Silicone-coated fiberglass is lighter in weight and less expensive than the PTFE coated fiberglass, but it does not offer PTFE’s reflective qualities or low heat absorption. For a variety of reasons, fiberglass-based fabrics have been the material of choice for stadium domes (both air- and cable-supported) and many other permanent structures. One reason is a perception that fiberglass’s high melting temperature and lack of “creep,” or long-term elongation, makes it superior to polyester. Because of the differences in how polyester and fiberglass perform in fire-resistance tests, PTFE-coated fiberglass is currently the only material that meets the model building codes’ definition of noncombustible materials.
Films and meshes for tensile structures: Films and meshes are the least-used materials. Films are transparent polymers, supplied in sheet form, that are not laminated or coated. Examples include clear vinyl, polyester or polyethylene. These films are cheaper than textiles, but they are neither as strong nor as durable. Meshes are porous fabrics, typically available as polyester weaves lightly coated with vinyl, or as knitted fabrics using high-density polyethylene (HDPE), polypropylene or acrylic yarns. They can provide shade as well as shelter from the wind, but as they’re porous, they aren’t good against rain. Still, they are inexpensive and have been used for some low-cost membrane structure applications. For obvious reasons, neither films nor meshes are used in air structure design. A newer fabric is 100-percent fluoropolymer, which has no polyester or fiberglass base. It is not as strong as other fabrics but offers excellent flexing ability. It is, however, very expensive.
Nylon: Nylon has most of polyester’s advantages, and it comes in a variety of weights. The translucency and drape of lighter nylons make them popular choices for interior banners. Heavier weights often are used for outdoor applications. Also, nylon and polyester are the fabrics most often used for flags. Nylon used for membrane structures is stronger and more durable than polyester, but it has a higher cost and more stretch.
Polyester: Polyester fabrics are woven or knitted polyester fibers that are coated or treated for durability, smoothness and printability. They are most often used to create lightweight banners printed on one side. Polyesters used for tensile structures—laminated or coated with vinyl films—generally are the most inexpensive for longer-term fabrications. Laminates usually consist of vinyl films over woven or knitted nylon or polyester meshes (substrates). Coated fabrics typically use high-count, high-tensile base fabric coated with a bondable substance for extra strength. In addition, the fabric can be laminated or painted to add a finish. Lighter fabrics (200 to 267 g/sq. m/6 to 8 oz./sq. yd.) are commonly used as acoustic and insulated liners suspended beneath a structure—heavier materials —665 to 865g (20 to 26-oz.) fabrics with polyvinyl fluoride (PVF, Tedlar® is an example) or polyvinylidene fluoride (PVDF, examples are Vidar® and Fluorex®) protective finishes are required for long-term exterior used. Polyester is the most-used base material for tensile structures because of its strength, durability, cost and stretch.
Spun-bonded polyolefin: Has a look and feel very close to paper. It is lightweight, very weatherable and low-cost. Typically used to create short-term, indoor/outdoor banners.
PTFE: Polytetrafluoroethylene (also known by its brand name, Teflon).
PVF: Polyvinyl fluoride (also known by its brand name, Tedlar).
PVDF: Polyvinylidene fluoride.
Topcoating: The coating intended for the front side, or “top” of a fabric or membrane. Similarly, the coating added to the finished side of a finished or treated fabric.
Unsupported films: Polyethylene and vinyl sheeting are lightweight, inexpensive banner plastics without any fabric reinforcement. Their smooth surfaces make them suitable for screenprinting. Be aware that they have a finite shelf life for banner-making and should be specified from recent inventory.
Vinyl laminates: These are constructed by sandwiching polyester, nylon or fiberglass scrims between two layers of vinyl. The scrim provides tensile and tear strength, plus dimensional stability; the vinyl offers a smooth, uniform surface for printing graphics. It is easy to make banners from laminates—they can be sewn, heat-sealed or RF welded. What’s more, most laminates meet the strict requirements of the California Fire Marshal. They can be used for nearly any banner, except where lightness and translucency are desired.
Vinyl-coated mesh: Used for banners, this material appears to be solid vinyl from a distance, but up close its open-weave design becomes apparent. Meshes are used where wind loads are a major factor. Wind simply passes through the open weave.
Graphics
Cut-out lettering: Good for simple graphics when easy readability (and economy) is essential. Images are cut out of the fabric and replaced from behind with translucent fabric.
Eradication: A graphics process that uses chemicals to wipe away a top-coated color from a white vinyl fabric. Especially useful for illuminated awnings.
Heat transfer: Images are baked into fabric using a large, expensive vacuum. It is very exact, creating bold color separation. However, it doesn’t blend colors well. And for a one-time project, it’s not cheap.
Ink-jet processes: Produces photographic quality images on nearly any material using a computer scanner. The images are rich and detailed, but the inks have a limited outdoor life span unless topcoated.
Laser: Large-image printing using a laser printer.
Pressure-sensitive vinyl: Vinyl film cut and then peeled from its backing and applied to the fabric.
Radio-frequency (RF) sealing: A fusion of two or more vinyl substrates using pressure and radio waves. Ideal for boldly colored, detailed illuminated awning copy, but not for incredibly sharp images.
Sewn-in graphics: Letters and forms cut from fabric and sewn on to the base fabric. When the letters are cut out of the fabric and replaced by different-colored fabric, they are called “cut-out letter.” (see above.)
Silkscreening/screenprinting: A process that transfers graphics onto another material using special screens. Ink is spread over the top of the screen and printed on the fabric face.