Caddis has long incorporated principles of biodiverse design in its projects. Along the way, we’ve befriended others who are interested in green building. Two individuals we’ve gotten to know – Andy Creath of Green Roofs of Colorado and Jennifer Bousselot of Colorado State University – are involved in the movement to create green roofs in urban areas.

Green Roofs for Healthy Cities, an industry association, provides an excellent introduction to the concept. A green roof provides a place for residents and visitors to interact with the natural world, to host pollinators, and if they like, to grow food. While green roofs are common in European countries, they are still in the developing stages in North America.

Green roofs create new spaces for city dwellers to enjoy. They provide many other benefits as well: aesthetic improvements, stormwater management, moderation of the urban heat island effect, improved air quality, energy efficiency, increased roof durability, fire retardation, and noise reduction. Most important, green roofs create increased biodiversity, improved health and well-being, possibilities for urban agriculture, and numerous educational opportunities.

Andy’s company, Green Roofs of Colorado, has worked in this space for the last 15 years and has crossed paths with Caddis frequently over the years. “We’ve had a lively connection, shared interests, and collaboratively spirited conversation with Caddis over the years,” says Andy, “and we have looked forward to someday being able to do a project together.”

That time has come as Green Roofs of Colorado and Caddis are now working together on a new project in Denver: The Co-op at 1st. Created by Jovial Concepts, The Co-op at 1st is a neighborhood space where training and community development are provided. They want to turn their rooftop into a place of action, a place to grow vegetables, and a space for meditation. Mordecai Children’s Garden at the Denver Botanic Gardens is their inspiration. They envision a wandering space where people can walk through and pause at places to sit, places to grow food, or places to just be together.

As a horticulture professor, Jennifer also focuses on green roofs, particularly in terms of plant collection and exploration of green roofs as good resources for pollinators. She’s especially interested in a type of green roof innovation called “agrivoltaics.” These mini solar-powered working farms generate energy for the buildings and also provide an ideal habitat for plants located under the solar panels.

Jennifer’s work with agrivoltaics was recently featured in an article in Wired. According to the article, “The panels would provide shade for the plants – actually boosting their yields – as well as for the building, simultaneously reducing cooling costs and generating clean energy for the structure.”

The potential benefits of agrivoltaics are far-reaching. “As people continue to migrate into metropolises,” says Wired, “rooftop agrivoltaics could both feed people and make city life more bearable.”

In a 2020 TEDx talk on the subject of rooftop agrivoltaics, Jennifer said, “Half of our world population lives in urban areas. Rooftops are the place that we need to be looking at for growing food.”

Andy and Jennifer are serving with others on Denver’s Green Buildings Ordinance Technical Advisory Committee. A citizen-led initiative to create green roofs in Denver passed in 2017. In 2018, the initiative was revised to focus more broadly on green buildings. The initiative went into effect in 2018.

Both Andy and Jennifer understand that green roofs – whether they provide places for residents to socialize with each other and be in the natural world or whether they provide opportunities for growing food – very much support biodiversity. This is all to the good in dense urban areas.

As Jennifer said in a recent issue of 5280 Magazine, “green roofs will help cities become more livable.”

Above: Lettuce, tomatoes, and peppers grow under a semitransparent solar panel array in a green roof system. This is known as rooftop agrivoltaics. Photo by Thomas Hickey.

Above: Outdoor rooftop therapy space at Della Cava Family Medical Pavilion, Boulder, Colorado. Photo by Andy Creath.