New sustainable advantages can be found by wrapping a building in fabric.
By Steve Fredrickson
Fabric façades are quickly becoming an important component in today’s architectural world, in large part due to their ease of design but, more importantly, as a means to drastically reduce energy consumption of buildings. This article is designed to not only educate readers on this particular method of construction, but also to point out its benefits to the environment, improvement of community, ease of use, methods of budgeting and, finally on how it all comes together.
Fabric façades are in fact a fairly simple concept, composed of an envelope component (fabric) that wraps a building façade, either in part or completely, supported by a structural framing system that is hung from the building face either as an add-on or integral to the building structural system if planned during design development.
Some of the primary reasons to utilize this form of construction include face-lifts, energy efficiency, advertising, and design. As with all textiles-based projects, professional manufacturers must be hired to perform and install final designs.
The most commonly used textile for fabric facades is coated mesh. The most common mesh is a PVC-coated mesh and from this there are two methods of manufactured mesh to choose from: coated and extruded. PTFE mesh, HDPE mesh, as well as new products on the market, are also available options. All products have their own benefits for use; the common link with all of the meshes is their ability to provide a view through the textile.
In recent years, European designers have started using solid membrane panels rather than just mesh. These provide a waterproof barrier and a higher degree of translucency than solid concrete or brick. The structural integrity of a textile must be kept in mind when selecting a textile as well. Remember, this membrane will need to provide all of the above needs — benefits to the environment, improvements to community, ease of use and so forth — as well as durability.
To date, there are four basic forms of framing used for textile facades: a rigid panel framing system, a laced-on framing system, a pocketed tension rod system and a keder-based system of framing. All four types of frames are constructed using steel and each offers various benefits.
A rigid panel system is an offset steel truss system designed to be lightweight and functional. Its benefits include ease of manufacturing, lightweight design and structural integrity. Its framing members will usually be manufactured off-site and shipped in sections to the job area. The fabric panels are typically stapled into some perimeter extrusion and remain locked in place. One limitation of this type of frame is the locking of the fabric into place; any wind that buffets this type of façade will cause some form of stress. This can easily be adjusted on-site with minimal cost.
A laced-on framing system is essentially the same as the rigid frame system, except “tie-back” bars are welded on the inside of the perimeter of the frame. Following installation of the frame, the fabric panels are laced into place using a grommet and lace line method. This method is common in the awning industry and allows for a good initial tensioning as well as ease of retensioning should an issue arise. In the past, typical lace lines were a major limitation because UV damage to polyester or other types of shock cords meant replacements were needed every year or so. However, today’s technology has provided the market with silicone shock cords, which have a much longer expected life span.
Another popular method for large- and small-scale façades is the pocketed tension rod. Fabric panels are created in individual sheets. Each length or width of material is pocketed and a steel rod inserted. These rods are then tensioned using turnbuckles to pull the panels into place. This method is most common for fabric façades using narrow panels or louvered systems. A common variation of this uses cables and steel plates for tensioning only in the corners, used when designing the louvered style façades.
A final method — a keder-based system — utilizes a bit of all of the above. Frames are created using an internal keder track, and fabric panels are inserted into the tracks and then tensioned into place behind the textile façade using springs. This method, first developed in Europe, is the most common form of attachment, primarily because the springs allow some buffeting of the wind while still holding the required tension, and it can be formed into many shapes while still maintaining tension.
Silver Spur, in Los Angeles, Calif., is one of the first projects installed in the U.S.
Silver Spur consists of a three-story commercial office building in an affluent Los Angeles neighborhood. The building’s owner was seeking a more energy-efficient building and XTen Architects, Los Angeles, Calfi., suggested several remediation solutions, including a textile façade. XTen’s first textile-based proposal called for a series of fixed panels angled off the building, not only increasing light reflection but also changing the building’s shape.
Installed on-site by a local awning manufacturer, this project took three weeks to complete. The total costs of this project are projected to be repaid in fewer than four years due to a 42% drop in energy consumption after installation.
An interesting note about Silver Spur is that the architect was able to integrate all of the benefits of the façade into its original design: a face-lift, a drastic reduction in energy consumption, a new look (which increased positive visibility in the region) and, because of the radical change and improvement, free advertising.
Nevertheless, advertising comes with a cost. One issue to consider when trying budgeting for a fabric façade is the addition of advertising costs. Often clients — such as sports facilities, universities and other public facilities — have no problem paying for advertising, especially if they can reap the benefits of energy savings. While most clients reject this notion as too crass or commercial, it’s not to be rejected out of hand.
Why create fabric façades?
Design is another good reason to utilize a textile façade. With a lot of new construction taking place in the form of concrete tilt-ups, a textile façade not only offers energy savings but also some texture to an otherwise flat building. Given that many of these new facilities face freeways or commercial zones, advertising is a popular method for paying for this type of construction. Rehabilitating a concrete tilt-up is also very popular because it could announce new ownership, create a cleaner, more desirable neighborhood and generally improve an office park.
In addition to all of the above, creating shapes is popular with designers and architects alike. Creating a texture on a building façade is a unique opportunity. By using the textile at an angle, light is deflected in a variety of directions and often utilizes colors to add more form. Recently, metallic colors have gained popularity and provide the same look of metal with less cost and significantly less weight.
Some final thoughts
Any window that is covered by a mesh textile will allow those inside to maintain their view. Textiles with a 15% open factor provide sufficient energy saving with almost no interruption of view from the inside. Knowing which type of framing you should use is important because you don’t want to have to re-tension something that cannot be removed from the framing once it is installed.
Using fabric is a very interesting method of creating a façade. It is lightweight, able to be shaped in form and color, is energy efficient and is a practical method for construction. Best of luck on your next project!