BOOST PERFORMANCE, REDUCE ANXIETY

One of the challenges of incorporating wood into the mix, Dunkley adds, is an increased focus on high performance, using today’s expansive definition that encompasses sustainability, energy efficiency, resiliency, occupant wellness, and low maintenance needs, among other attributes. Yet some architectural solutions have found a way to serve both needs with creative design ideas and rigorous specifications.

Photo courtesy of Longboard – A division of Mayne Coatings Corp.

Natural imagery and materials have been shown to reduce stress in building occupants, which benefits the administrators and residents at the John Paul II Pastoral Centre in Vancouver, British Columbia.

For example, for a mixed-use facility for a Campus of Care called the John Paul II Pastoral Centre in Vancouver, British Columbia, the Burnaby, British Columbia-based firm John Clark Architect Inc. sought to connect the building image to the outdoors in ways both explicit and subtle. The facade cladding was envisaged with the color and grain of light cherry, selected because its “red tones best contrasted with the adjacent Douglas fir and yew trees,” says principal John Clark. The wood aesthetic would also serve as a hallmark of the John Paul II center’s visual branding, and just as critically connect the architecture to its region and place. The second of five phases for the Campus of Care, it is a four-story building with administrative offices, an auditorium, chancery, chapel, 10 senior housing units, and an underground parking deck. The architect specified woodgrained aluminum siding material because of its “aesthetic compatibility to wood finish and noncombustible designation,” he says, adding that codes do not permit the use of wood soffit for a noncombustible type.

The $18 million facility was conceived for efficiency and sustainability, yet it was also focused on creating a harmonious, warm, and serene location for health-care services. “This small woodland contributes to the creation of a quiet and peaceful environment separate from the office functions and use,” according to the owner, the Archdiocese of Vancouver. “With paths connecting to the wellness walkway, this quiet oasis will be accessible to the occupants and visitors.” For optimal patient outcomes, the client required a LEED Gold-certified building fully accessible by wheelchair and a fragrance-free space.

Photo courtesy of Longboard – A division of Mayne Coatings Corp.

Designed by John Clark Architect, the John Paul II Pastoral Centre employs a woodgrain aluminum soffit and cladding in 6-inch, V-groove panels.

With these aims in mind, the architects compared facade systems, including aluminum composite, cementitious plank, and steel cladding. Ultimately the design included metal cladding and 10,000 square feet of 6-inch, V-groove aluminum siding and soffit in the light cherry woodgrained pattern. Architect John Clark notes that the wood-look exterior panels resist shrinkage and staining, making them a durable and resilient selection. With its hidden fastening system, Clark says, the system is almost impossible to distinguish from a real wood rainscreen. Most important, he explains, “The scale and color of the 6-inch plank material relative to the volume of the wall areas and feature elements informs and strengthens the relationship of the forested southwest edge of the property, its tall trees and adjacency to the residential neighborhood, and the neighboring health-care facilities.”

The site’s steep grade changes and a “small woodland”—a stand of mature evergreen trees wrapping its southwest corner—“contribute to the creation of a quiet and peaceful environment separate from the office functions and use,” according to the Archdiocese of Vancouver. In this way, the facility is essential to its goal to “better suit the needs of the elderly” and an integral part of the renewal and redevelopment of the health care provider’s residential care facilities.

MATERIAL CONNECTION WITH NATURE

Two key lessons stand behind this case study: first, the use of wood patterning and grain is a way to deploy what sustainability consultant Terrapin calls “natural analogues” for biophilic design. In its 2014 research paper “14 Patterns of Biophilic Design,” Terrapin describes three types of natural analogues: biomorphic forms and patterns; material connection with nature; and complexity and order. The connection with nature can include woodgrains as accent details, woodwork, wood facade materials, and timber structures, among others.

The goal for material connection with nature, write Terrapin’s William Browning, Hon. AIA, and Catherine Ryan, along with Joseph Clancy of Pegasus Planning Group Ltd., “is to explore the characteristics and quantities of natural materials optimal for engendering positive cognitive or physiological responses.” They cite the multiple “layers of information” in materials that enhance this connection, “such as learned knowledge about the material, familiar textures, or nested fractals that occur within a stone or wood grain pattern.”⁴

The second lesson from the John Paul II Pastoral Centre is the significance of facade cladding systems in overall building design, durability, and sustainability. For example, wood-look metal claddings are lightweight and resilient, meaning they can be exposed to the elements for many years, while also reducing the dead load from the cladding system, potentially reducing the size of structural members, while still effectively protecting the structure. The wood-look aluminum panels for soffit and siding are tested to be noncombustible, maintenance free, 100 percent recyclable, and resistant to warping, rotting, and splitting. (The architect Clark considers the fade-resistant aluminum cladding to be a zero-maintenance selection, noting the product is warrantied for 15 years for the factory-applied finish.) In terms of low-emitting materials, the high-performance powder coating is 100 percent free of VOCs. These qualities deliver building owners all the aesthetic aspects of real wood, yet with a generally more durable facade system.

Properly maintained, woodgrain aluminum can last 40 years or more, according to the association of commercial and residential property inspectors, InterNACHI, which publishes an estimated life-cycle chart. With life-cycle assessment (LCA) a more prominent aspect of LEED certifications, more architects are reviewing independent data on building systems.

The structural performance of the fastening clips has been studied and verified by the engineering firm Morrison Hershfield. In addition, another recent study by Morrison Hershfield, released in early 2014, shows that the sub-girt system cladding clips have been optimized for thermal performance by reducing thermal bridging, in which unwanted heat gain or loss are carried by metal elements through the insulated enclosure plane. As with other opaque panels, the coated aluminum materials can help reduce the window-to-wall ratio (WWR), increasing thermal resistance (R-values) and reducing overall enclosure U-factor, the measure of rate of heat loss.

For these and other reasons, wood-look exterior cladding systems can contribute to several LEED credits needed for the various U.S. Green Building Council (USGBC) certification programs. With fully recyclable content, aluminum building products count toward Materials and Resources (MR) credits. The cladding materials can be used for green building applications indoors as well, as the finished metals are benign and give off zero emissions, contributing to Indoor Environmental Quality (EQ) credits. The manufacturing process, which utilizes a sublimation powder coating process, does not utilize any volatile organic compounds (VOCs) or the toxic heavy metal chromium VI (also known as hexavalent chromium, which the International Agency for Research on Cancer has listed as a carcinogen). This element is typically used to produce chromed metal finishes.

In addition, for the important LEED credit for Optimized Energy Performance, which offers the most points toward certifications, wood-patterned aluminum systems can contribute to effective designs. The backframing allows for continuous exterior insulation, shown to be 40 percent more effective than interior insulation assemblies, according to the Morrison Hershfield report on the thermal performance of the sub-girt system’s fastening clips. This type of assembly with external insulation also helps provide a thermally comfortable interior environment, with fewer cold spots or hot spots.