In the still-developing building and construction segment, composites adoption has been slow. Laudable efforts by the American Composites Manufacturers Assn. (ACMA, Arlington, Va.) to modify the International Building Code (IBC) and a growing awareness of composites’ environmental sustainability through lifecycle analysis tools had previously earned the composites industry only small gains in what architects call the building envelope. Exterior decorative elements, such as cornices and columns and, more recently, window lineals, entry doors, skylights and light panels represented a beginning. But many industry observers saw tremendous opportunities for composites in structural wall panels, foundations, building cladding and roofing. In 2013, there was compelling evidence that the architectural community was, at last, taking notice.
Composites bring to architecture the same benefits that other sectors have exploited. At 20 percent of the weight of stone or concrete cladding, a composite exterior can significantly reduce building dead load, which translates to a smaller foundation, a more manageable seismic design and smaller construction crane requirements. This results in material and cost savings that cascade through the entire project. Further, composites’ durability and weather resistance mean less maintenance and cleaning cost over time, an issue that is especially important for city-owned buildings, which often have to undergo cleaning. As candidate materials, composites also offer design flexibility that feeds an architect’s creativity — unusual forms that are not feasible with traditional materials. Further, lifecycle analyses have shown that composites are actually more environmentally sustainable than concrete, aluminum and other conventional building materials
In a huge step forward, composites have made headway into building codes: — the IBC, published by the International Code Council (ICC, Washington, D.C.), the Eurocode or country-specific codes used in Europe; and in the Middle East and Asia, codes that tend to be a mix of U.S. and British standards. In 2009 the ICC voted to allow the use of composite materials for both interior and exterior wall applications, as reflected in the code’s latest edition: IBC Chapter 26, “Plastic,” and Subsection 12, “Fiber-Reinforced Polymer.”
In essence, the IBC says that FRP can be used on the exterior walls of a building of any type of construction, provided the materials are noncombustible or meet certain requirements laid out in Section 2612.5.
Architect Cornelius DuBois, a fellow with the American Institute of Architects (AIA, Washington, D.C.) notes, “Architects are always intrigued by new materials. If they can perform and meet code, and provide some unusual capability, then it’s worthwhile, despite added cost.” He points out, for example, that a lightweight, insulated curtain wall system that could be produced in large sizes, reusing molds to minimize fabrication cost, would be attractive and would require fewer “picks” with a crane, expediting installation.
In 2013, that possibility became reality, as developers sought durable, lightweight façade panels for exterior applications on high-rise structures once off-limits to pervasive use of composites. Some manufacturers of composite products are already well entrenched in the exterior cladding market, particularly the flat panels used in rainscreen applications. Trespa International BV (Weert, The Netherlands), for example, produces flat, compact composite high-pressure laminate (HPL) panels trademarked Meteon. Used as a decorative exterior panel in ventilated rainscreen systems supported on an aluminum frame, Meteon contains roughly 70 percent cellulose kraft paper in a phenolic resin matrix. Panels are pressed at high temperature and pressure and are cured using a proprietary electron-beam process. The result is a highly durable panel with good UV resistance and an integral surface finish, available in multiple colors and textures.
Similarly, Acell (Milan, Italy) specializes in exterior insulated composite panels that can mimic brick, stone and other traditional finishes. Featuring a phenolic foam core between sheet molding compound (SMC) composite skins, the panels can be used to re-sheath existing structures yet preserve the look of the original. In addition, they can be used to form A-frame structures for Acell’s Compass modular house concept. Factory prefabricated, with one side finished for exterior exposure (e.g., faux brick) and the other prepped for interior finish, the panels are shipped to the build site in flat packs. The kitted components are assembled easily and can be arranged in many configurations (read more about composite exterior building panels in “The building envelope: Betting on the big time,” under Editor’s Picks” at top right).
Although the ease, low cost, simplicity and commoditized availability of flat-panel designs is attractive, architects are finding that composites are anything but geometrically confining and, unlike other materials, have the potential to make practical even the most imaginative of architects’ dreams. “Designers are getting away from ‘flat,’ today,” notes Bill Kreysler, president of Kreysler & Assoc. (American Canyon, Calif.) “It’s now possible to produce via CAD the entire design for a building, including the electrical, insulation … everything. Those data files can be transferred seamlessly to cutting tools to create the tooling for exterior panels.”
In residential construction, composite decking and railing continue to grow. The Freedonia Group (Cleveland, Ohio), in its Wood & Competitive Decking to 2016 market study, predict that U.S. demand for decking is forecast to rise 2.4 percent annually through 2016 to 3.3 billion lineal ft, (about 1 billion m) valued at $5.7 billion. Wood-plastic composite and plastic lumber decking materials will grow at double-digit rates, far outpacing the dominant wood segment.
The Freedonia Group also maintains that the 166 million ft2 (15.4 million m2) U.S. cast polymer market is predicted to increase 5.4 percent annually through 2014, driven in part by gains in market share over laminates in countertops. Solid surfaces will remain the most common cast polymer, but engineered stone will grow the fastest. Doors, window frames, bathtubs and other elements of home construction and remodeling are also on the upswing, says market research firm Lucintel (Las Colinas, Texas), because of stronger market penetration in comparison to traditional materials. In European markets, Lucintel predicts a total market size of $2 billion by 2016 for composites in construction.