The pursuit of green design has inspired the literal greening of architecture. Natural landscaping not only provides aesthetic benefits for a building and integration with its environment, but valuable enhancements to building performance as well. In Western history, architecture and its natural context have long been considered distinct territories. However, as a result of the increased construction of green roofs, vertical gardens, and smart landscape-retention strategies, the traditional boundary between architecture and landscape architecture is becoming blurred.
This disciplinary convergence is proving to be rich territory for the exploration of new materials, systems, and design approaches. It is also leading to intensified challenges and conflicts that arise when living and inert materials mix—especially at the line of the building envelope. Innovations along this line are shaped by the water costs and other challenges associated with these designs.
Direct application of foliage on external building surfaces has multiple benefits, including thermal and acoustic insulation, stormwater control and filtration, bird and insect habitation, and visual appeal. Other benefits extend beyond a building’s site, and include mitigating the urban heat-island effect and cleaning the air. The roof is an obvious location for greening, and many systems incorporate landscaping on the top surfaces of buildings.
Green walls have also become popular, and range from lightweight trellis systems to comprehensive vertical gardens—such as Tokyo-based Shimizu Corp.’s Parabienta, a building afforestation system made of a special growing medium supported in steel wire frames with integrated irrigation. Likewise based in Tokyo, Japanese architect Terunobu Fujimori approaches the notion of foliated envelopes differently, appreciating the messy, viral quality of living materials on architectural façades. His Tanpopo (Dandelion) House, for example, features walls with integral planters for flowering plants that make the building appear fuzzy and unkempt—a celebration of the convergence of living and inanimate matter.
Mature vertical gardens often result in masked architectural surfaces completely covered by foliage. However, a variety of innovative systems partially shelter plants within the wall cavity, and support exterior and interior environments alike.
Los Angeles–based Greenmeme has developed several vegetated wall assemblies that may be used outside or inside, and are designed to oxygenate air for building occupants. Live Within Skin produces a steel wall perforated with plant cavities filled with coco-coir growth medium. Another Greenmeme system, Mypodlife, is made with Corian and includes LED strip lights for a dramatic backlighting effect. And the Austrian company Experimonde offers a membrane curtainwall that provides space for a domestic garden. Designed for residential retrofits, the Pneu-Green Façade is an inflatable cladding system that acts as a matrix for planting, using both foliage and air as thermal insulation layers.
Not only is landscaping infiltrating the architectural envelope, but more thoughtfully designed rigid systems are also being incorporated within landscapes. Silva Cell, by San Francisco–based DeepRoot Green Infrastructure, is an integrated tree and stormwater management system made of glass-reinforced polypropylene and galvanized steel tubes. The stackable modules protect tree roots from traffic loads and absorb stormwater while improving tree canopy cover.
Like Silva Cell, the U.S. National Ready Mixed Concrete Association’s Pervious Pavement promotes the recharging of groundwater. The cement and course aggregate paving material allows drainage at a rate of 8 to 12 gallons per minute per square foot, replenishing aquifers as opposed to diverting water to storm sewers. From Portland, Ore., comes Flextegrity, which combines the functionality of both systems. A structured polyhedral geotextile made of recycled plastic, Flextegrity is appropriate for permeable paving and preassembled sidewalks with integrated lighting and drainage. Its interlocking polyhedral shapes allow it to resist localized forces.
Although the many applications mentioned here deliver many benefits, architects are understandably nervous about the junction between building materials and living systems. The pervasive presence of water in particular has caused more than one architect to shy away from a green roof or vertical garden. Foliage also requires more maintenance than typical building surfaces, and can accelerate the degradation of building components.
Even Fujimori admits to having exceptional clients for his foliage-covered buildings. “Normal clients,” he says, “probably wouldn’t forgive me for the level of upkeep required.” But the benefits of the convergence of natural and architectural systems often outweigh the potential pitfalls. And improved materials, sophisticated hydrophobic coatings, and tighter detailing can ward off some of the worst degradation problems. More importantly, the creative collaborations of architects and landscape architects can result in innovative applications that neither side could achieve alone—which is a positive outcome indeed.