Introducing the AWSOM Green Roof

Alice L. Walton School of Medicine’s 154,000-square-foot medical education facility is under construction near Crystal Bridges Museum of American Art and Heartland Whole Health Institute in Bentonville, Arkansas. The campus will bring together nature, art, architecture, and well-being to create a one-of-a-kind learning environment for students and the community. In addition to natural spaces such as healing gardens and outdoor classrooms, the School will be home to a 2-acre green roof, the largest in the region.

The green roof was designed by OSD, an interdisciplinary architecture and planning firm focused on sustainable and resilient environments. For installation of the roof, the School has partnered with Northwest Arkansas-based company Ozark Green Roofs (OZGR). Since its founding in 2018, OZGR has provided a full spectrum of green roof services and completed green roof projects in Northwest Arkansas such as:

 

• Fayetteville Public Library expansion
• First National Bank of NWA
• Uptown Apartments
• Adohi Residence Hall

 

OZGR’s expertise is a perfect match for the School’s green roof, which will function as a “rooftop park”, seamlessly connecting to Crystal Bridges’ trail system. The roof will expand the natural environment surrounding it by featuring over 90 native trees, shrubs, perennials, and other plants. Some of the local flora that will call the roof home include red buckeye, chinquapin oak, catalpa, sumacs, and redbuds.

Lee Porter, Owner of OZGR, expressed her enthusiasm about the project, saying, “The green roof at Alice L. Walton School of Medicine will be an extraordinary result of collaborative design excellence from the project’s design team. We are honored to be entrusted with the task of bringing the School’s visionary design to life. The project aligns perfectly with our mission to create spaces that benefit both people and the environment.”

The History of Green Roofs

 

Green roofs date back to ancient times, where they began as sod roofs above caves and other dwellings. These roofs served a utilitarian purpose of protecting and insulating the structures below them. Sod roofs would come to be commonplace on houses in Scandinavia in the 18th and 19th centuries.

 

Modern green roofs were developed and popularized in Germany in the 1970s. In recent decades, the innovation has spread to North America, with notable green roof initiatives being launched in Seattle, Denver, and Washington D.C.

 

There are two categories of green roofs: extensive and intensive. Extensive green roofs have a thin layer of growth and host low-maintenance plants adapted to roof conditions.

Green roofs with more than six inches of growth are considered intensive. Intensive roofs are heavier and can accommodate taller plants and even trees, making them the best fit for the School’s ambitious rooftop park.

The School’s intensive green roof will be constructed on top of several layers of Geofoam, a lightweight, geosynthetic material often used to construct green roofs and retaining walls. In some parts of the roof, the Geofoam layer will be over 12 feet thick.

According to Porter, OZGR will be employing some unique construction methods for the project, such as using a soil blower to transport soil onto the roof. This method reduces material waste and improves efficiency.

Why Go Green?

In addition to their aesthetic value, green roofs have many environmental benefits. Green roofs can help combat “heat islands” (pockets of heat that occur in urban areas with limited green space) by providing shade and cooling the air. They can also improve air quality through photosynthesis, increase biodiversity, and extend the natural habitat of local flora and fauna. In 2023, NYC Audubon recorded 51 different species of birds living on the green roof network at the Jacob K. Javits Convention Center in Manhattan.

On the structural side, green roofs have a longer lifespan than traditional roofs and can act as a sponge to absorb heavy rainfall and reduce flooding risks. The insulation provided by green roofs also reduces building energy usage. A 2011 report by the Government Services Administration found that a green roof reduced the amount of energy needed to cool the top floor of a three-story building by 21 times.

A Healthy Environment

Out of the many benefits a green roof can provide, the increase in overall well-being aligns strongly with the School’s vision for whole health.

Green roofs, like other natural spaces, come with many mental and physical health benefits. In 2022, researchers from Montclair State University found that hospitals with green roofs were associated with improved mental health, increased physical activity, and shorter hospital stays for patients. The roofs were also found to increase overall satisfaction for patients and staff.

Pending accreditation, the School plans to matriculate its first class in 2025. The School’s green roof will offer students, faculty, staff, and the community a unique and enriching environment to learn, explore, rest, and connect to each other and the natural beauty of the Ozark setting.