Any product junkie knows many innovative developments happen overseas. The international community's willingness to experiment with cutting-edge materials has yielded architectural favorites such as fiber-cement siding, wood-resin exterior panels, and cellulose-wood laminated cladding.
Another import now making incremental inroads in this country is the ventilated façade—a wall system many architects and building scientists cite as one of the most effective ways to clad a building. Unlike typical stick-built framing, a ventilated wall is a complex multilayer system (similar to a rainscreen) that creates a 3-inch to 7-inch air space around a building. Insulation is applied on top of the sheathing instead of within the wall cavity, resulting in a wall construction comprised of studs, waterproof sheathing, a vapor barrier, rigid-foam insulation, an aluminum frame, and wall covering.
What makes the system so great? According to Richard Stacy, AIA, a principal at San Francisco-based Leddy Maytum Stacy Architects, ventilated façades are better designed “to avoid water intrusion because the pressure behind the cladding is equalized with the exterior.” There's also “less thermal transfer and better R-value because of the air space,” he says.
Michael P. Johnson, principal of Michael P. Johnson Design Studios, Cave Creek, Ariz., says ventilated façades are better for the environment, too. “The chimney effect the system creates causes cool air to pass over the insulation and warm air to exit out the top of the wall,” he explains. Because the building is constantly being ventilated, the result is a more energy-efficient house—up to 30 percent more efficient—that stays cooler in the summer and warmer in the winter.
Contractors who've worked with the systems second the point. “It's about the most effective wall you can have in the summertime,” says Dave Traino, CEO, Carmel Architectural Sales, an Anaheim, Calif.-based provider of exterior building envelope solutions to the architecture community. “In the winter,” he adds, “it's the same deal.”
Constant ventilation also creates a powerful moisture-management system that helps to eliminate mold. Because of the way it's installed, the cladding resists about “90 percent of the water” that comes into contact with it, says Kelton Dissel, an associate at Paulett Taggart Architects, San Francisco. The rest, he says, “evaporates quickly.”
Beyond increased efficiency, a ventilated façade offers other tangible benefits. According to Peter Lollias, architectural sales division president in the Saddle Brook, N.J., office of Porcelanosa USA (a Spanish ceramic tile manufacturer that offers ventilation façades), the system “acts as a sound barrier, is easy to clean, and requires minimal maintenance.”
on tileFor some architects, the environmental benefits and versatility of a ventilated wall can't be beat. Its grid system can be configured to accept a wide range of materials, including stone tiles, cement board, Parklex or Prodema resin-wood panels, and Trespa cellulose-wood laminate.
Recently, Italian and Spanish ceramic tile manufacturers have been spreading the word that tile is one of the best cladding options available. Ceramic porcelain tiles “guarantee the best performance obtainable and desirable,” according to a presentation by Arturo Mastelli, a consultant for Ceramic Tiles of Italy and president of AM&A Marketing in Key Biscayne, Fla. “They are mechanically strong and physically resilient to most of the hardships [that deteriorate] exterior walls.”
Johnson, who is doing a house in Italy with ceramic tile, agrees that the qualities which make tile an ideal material in normal applications make it perfect for ventilated façades, too. “Tile lasts forever,” he says. “And if you use a polished porcelain tile, it becomes self-cleaning.”
Most Italian and Spanish tile companies—among them Iris Fabbrica Marmi e Graniti, GranitiFiandre, Tau Cerámica, and Alcagres—make ceramic cladding for walls, but some companies offer the entire system. American Marazzi Tile, the U.S. division of the Italian outfit, is one example; its Tecnica system includes the tiles, framing grid, and rigid fiberglass insulation.
Ventilated façades' longevity, environmental benefits, and design versatility have made them especially popular in Italy and Spain, where they grace many buildings and residences. Architect Renzo Piano used a system with terra-cotta cladding for his Rue de Meaux low-income housing project in Paris. Many of the new multifamily buildings in Germany also feature ventilated systems. And in Russia, the transition to monolithic frame construction with external insulation and unventilated and ventilated façades has been partially responsible for the reduction in the country's energy use for heating over the past eight years.
piece de resistance?
Traino, a 10-year veteran of ventilated façade installations, says the United States might be the only country that has not fully embraced ventilated walls, and there are a handful of theories why this is so. One belief is that unfamiliarity with the system makes people suspicious. “Innovation and creativity are dirty words to government agencies, bureaucrats, and code officials,” he reasons. “There is a tremendous resistance to innovation, so the system is scary to a lot of people.” Dissel has a slightly different take, however. “Things seem to start in Europe because there are less code restrictions,” he says. Here, he adds, “we have to show code officials that a system can work.”
Traino says American designers and clients also resist ventilated systems because they don't mesh well with our construction culture. “Everything is done efficiently and quickly, but a ventilated wall is a labor-intensive process,” he says. That makes it expensive, too—a reality that Stacy says may be its biggest obstacle. “There is a premium in cost over conventional cladding,” he says. “I think this is largely due to the lack of experienced installers and the greater degree of sophistication required of the installer.”
Although the average cost of a ventilated façade is $40 to $75 per square foot, it's possible to reduce those numbers. GranitiFiandre says smaller slabs require more substructures to hold them in place, increasing the structural and application costs. Larger slabs, by comparison, require less substructure; they're therefore quicker and cheaper to install.
Despite the cost, Traino says more architects in the Northeast, Chicago, California, and Seattle are using such systems in their buildings. Italian firm C&A Architecture and Interiors recently used Marazzi's ventilated system to clad an Arizona house in large 24-inch-by-24-inch ceramic. In San Francisco, Paulett Taggart Architects and Leddy Maytum Stacy used a modified ventilated system with wood-resin panels over rigid insulation for the Plaza Apartments, a LEED-certified low-income housing project that has won numerous awards for sustainability. “The concept is similar to a ventilated wall,” Paulett Taggart's Dissel says of the façade. “It allows air to pass around the insulation material.”
In addition to the Plaza Apartments, Leddy Maytum Stacy has used ventilated systems on an office building, a condominium, and two houses. Stacy agrees that the concept is catching on here, but he wouldn't be surprised to see it remain a niche product. “I think it will be limited to higher-quality residential buildings due to cost,” he says.
Nonetheless, for those with the nerve, verve, and budget to try them, ventilated façades are a breath of fresh air.