Strategies for More Sustainable Exterior Solutions

From growing walls to glowing glass, professionals can choose sustainability through the use of exterior building products that will help conserve water resources, manage living systems and daylgiht.
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Sponsored by Formulated Solutions LLC, greenscreen®, IRONSMITH, Jockimo Inc., Kim Lighting, SOIL RETENTION, YKK AP America Inc.
Celeste Allen Novak AIA, LEED AP

Example of a corner detail for a building sunshade.

Photo courtesy of YKK AP America Inc.

 

STRATEGY #1: Measure 4: Bioclimatic Design - building living habitats
Sustainable design conserves resources and maximizes comfort through design adaptations to site specific and regional climate conditions.

The Vertical Wall −designing for living habitats and energy efficiency

The headquarters of the National Wildlife Federation is nestled into a wildlife area. Designed holistically, the massive planted screen wall on the south facing exposure is both a natural habitat as well as a mechanical system that reduces heat gain on the wall's exterior facade. Indigenous deciduous vines were established to provide leafy shade in the summer and streaming sunlight in the winter. The three dimensional metal grid was engineered for the climate and cooling for the southern exposure of the building.

Providing a living green façade on, or adjacent to, buildings is beneficial for two main reasons. First, they are systems that can increase the performance of the mechanical system by providing both shade and natural cooling. When planted screens shelter rooftop mechanical systems or building facades, they protect the units from heat island gains and hot rooftop areas. Air that is tempered around the mechanical system reduces the cooling load; less energy is required to cool the ambient air to room temperature. Secondly, planted screens create a transition zone that incorporates nature into architecture when used to shade a building façade. Modular, stacking green wall systems should be rigid, light weight and engineered to meet required spans and design loads.

Planted green walls should have structural capability and can be attached at the perimeter of a wall system. Systems are available that can span from 8 feet to 12 feet and that can resist a 90 mph wind load. Some important criteria for professionals to consider include:

  • Remember that green wall panels are designing with a living system that changes as it grows.
  • Think about the importance of materials used to create the metal grids and choose systems that use a high percentage of recycled steel as part of a more carbon neutral design strategy.
  • Review plant materials with a landscape architect or horticulturist. Living systems can take a while to mature and depending on the climate zone or urban environment should be chosen for adaptability and longevity.
  • Account for the water, nutrient and drainage conditions that will change as the plant grows.
  • Don't underestimate the time of growth, and provide information to the building owner on the reasons for investing in the maintenance of this living system.

Photo at installation showing the gap between the future green façade and the building.

A similar view of the National Wildlife Headquarters after plant growth has created a living environment away from the building.

 

One of the latest trends in using green walls is to create vertical gardens in multi-storied buildings. When designing at elevated surfaces, the professional needs to design this system as a series of elevated planters, understanding the solar orientation and wind loads as well as providing a means to convey water to raised floor platforms. Some of the future advances in green grid façade technologies will be the incorporation of gray water systems to efficiently support the building's long term integration of the plant areas, providing nutrients to the plants as well as water purification.

Vertical planting systems are also an important opportunity to contribute to community habitat planting. As shown in studies like Lloyd Crossing, by Mithun Architects, calculations can be made that reestablish native habitat, species, birds and plants to maintain a sense of place, expanding from the familiar horizontal approach to the building site to include its vertical wall surfaces. Planted green wall systems can provide the place for bird songs, providing an acoustic buffer from the street.

From a planning or community perspective, cities are often requiring more sensitivity toward the creation of place. Parking structures and large blank walls on commercial buildings can become assets rather than eyesores by the placement of vertical green walls. Using planted vertical green walls can assist the professional in obtaining credits in virtually every category of LEED® V3 including site development, water efficiency, regional credits, energy efficiency, recycled content and innovation.

Planted green walls are an innovative way to make an aesthetically pleasing and natural habitat for the entire biology of the building site and the neighborhood of a locale in a new built facility.

 

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Originally published in Architectural Record
Originally published in November 2009

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