Green Roofs

Op Het Dak’s rooftop garden and what Raleigh could learn

While we were in the Netherlands, our group had the chance to visit several sites that put their rooftops to use in creative ways. One that I found particularly interesting was Op Het Dak in Rotterdam. Op Het Dak is a rooftop garden with a bistro that overlooks Rotterdam’s city center. Instead of letting their rooftop be a waste of space, they allow it to serve many functions leading to an array of benefits. Increasing green space and decreasing impervious surface on a roof helps the city better manage storm water runoff. This will become even more important as the climate is changing and larger volumes of water fall during a given rainstorm. This specific installation stored rainwater under the initial layer so that plants were able to absorb the water during dry periods. By implementing green roofs, cities can use this space in a way that helps them to be more resilient to the effects of climate change. Rotterdam is even paying half of the cost for green roofs when implemented on private rooftops. They are doing this because they realize that it is cheaper to help subsidize the costs of these projects as opposed to investing in large-scale water/sewage infrastructure. These projects have other environmental implications such as absorbing heat to reduce the city’s urban heat island effect, while making the buildings more energy efficient. These types of installations on roofs are perfect for cities looking to manage their storm water runoff in a way that is cheaper and doesn’t involve large infrastructure investments. Another important aspect of Op Het Dak’s rooftop is its garden. This garden produces produce that is used at the rooftop bistro, as well as providing flowers for local restaurants and businesses. Volunteers are allowed to help work in the garden during special times, which is a good way for citizens to get involved and learn more about the importance of rooftop gardens while establishing connections with those that they are working with. The green roof and the garden incorporate plants that attract pollinators, which make a great home for the beehive located on the roof. This is both important for increasing pollinators and biodiversity in an urban environment, as well as for educating the volunteers and patrons of the bistro about the significance of pollinators. Using the produce from the garden in the bistro allows customers to have access to fresh food while exposing them to how it is grown. This helps create a stronger connection between people and the food that they consume because they can see where it is coming from and the people who help grow it. Op Het Dak provides citizens with a rare oasis of green space in the middle of the city center. This project has, in turn, helped increase the investment in the surrounding area making it more attractive to the city. This site incorporates a creative use of space yet a fairly simple idea, which can be easily replicated. As the population continues to grow, cities will have to use their space more efficiently, and Op Het Dak serves as a good example for how to do so. The variety of functions that a project like this brings are useful for cities trying to revitalize their downtown because it increases the value of the surrounding land, leading to further investment in the area, as well as the project being environmentally conscience, which is necessary for planning sustainable and resilient cities.

The green roof on the building serves as a home for pollinators, while helping manage stormwater runoff and reducing the city’s urban heat island effect.
Flowers on the rooftop garden that are sold for local restaurants to use in their stores. Until picked for an arrangement, they serve as a great home to pollinators and make for a lovely view.
Our group exploring the rooftop garden before eating lunch at the rooftop restaurant. This section of rooftop houses a beehive, produce to be harvested, flowers, and a place to compost.
Op Het Dak is the rooftop bistro and garden located in Rotterdam. Here, they grow fresh produce for their restaurant while providing green space for their patrons to enjoy while they look out over Rotterdam’s city center.

As an urban area like Raleigh continues to grow, they must be foreword thinking in how they use space available to them, while doing so in a way that is good for the environment and green roofs are a perfect way forward. Raleigh could learn from European countries like Germany and the Netherlands, or even a city closer to home like Chicago. Some multifunctional roofs are present in Raleigh, but the city could take this opportunity to be a leader in green roofs in the southeast. Projects like these would be important in lowering the cities energy use, especially since cooling takes up the largest share in electricity usage for buildings. Green roofs would not only have environmental consequences like better storm water management, increasing urban air quality, and decreasing urban heat island effect, but it would also make the city more attractive for future growth. These features can also serve as an opportunity for public education on the importance of such projects. Furthermore, the city could partner with NC State’s engineering and architecture departments to help design green roof plans to take advantage of local knowledge, while giving students real world experience. On top of the economic opportunities Raleigh has to offer, these installations would make the city more appealing for young professionals. This would lead to more companies being drawn to the area, further setting the city apart from its peers. Many companies are looking to settle in areas that have a strong pool of young professionals and that are environmentally friendly. This is a good example of how the built environment plays a role in impacting the economics of a city.

-Stephen Lapp