Month: June 2023

GREEN ROOFS ARE NOT NEW: The Hanging Gardens of Babylon (c. 500 B.C.) were one of the Seven Wonders of the Ancient World and an early version of a green roof, with gardens cascading over scone pillars and roofs waterproofed with tar and reeds. Green, or sod, roofs have been around for centuries, ­think “Vikings” in Scandinavia and the sod roofs of American settlers on the Great Plains. A precursor for the modern green roof was unveiled in 1867 at the World Expo in Paris featuring a waterproofing and drainage system. The 1920s and the 1930s yielded innovations by Le Corbusier, Alvar Aalro, and Frank Lloyd Wright. Their installation has increasingly expanded in Germany as practitioners improved the technology to use on existing and new buildings to proactively reduce stormwater runoff due to development.

Green Roofs for Healthy Cities defines a green roof system as an “extension of the existing roof which involves, at a minimum, high-quality waterproofing, root repellent system, drainage system, filter cloth, a lightweight growing medium, and plants.” Basically, a roof that is covered or partially covered in plants.

Common concerns about green roofs typically focus on integrity, maintenance, and cost. Although any type of roof can leak if not properly installed, green roofs installed by experienced contrac­tors are much less likely to leak. While it is true that the first cost of a green roof installation, either for a new or existing building, can initially be higher than that of a typical single-ply membrane roof, the costs for a well-designed and site-appropriate green roof are often balanced by its long-term energy savings and the fact that the green roof will extend the life of the roof membrane.

Every green roof is unique, not only to the building and space it defines, but also to the local climate, and proposed use offering many benefits associated with such an installation. The most widely acknowledged ones are associated with environmental sustainability-specifically, stormwater management, water conservation, air quality, and mitigation of the heat island effect in dense urban settings. In addition to its benefit as an amenity, a green roof can also improve building performance through better mechanical performance and more efficient PV systems, as well as reduce acoustical transmission through roof assemblies.

The design of a green roof provides a blank canvas upon which to introduce biodiversity while contributing to the improved health and wellbeing of users. Many hospitals now include healing gardens on accessible, visible roofs because they can have such a positive impact on patient recovery. In the right setting, it can also serve as an effective educational tool, adding to its justification on new and existing school buildings.

As a practitioner of sustainable design promoting the responsi­ble use and conservation of natural resources, HMFH has had opportunities to leverage this expertise by helping three Massa­chusetts schools—Saugus Middle High School, Josiah Quincy Upper School, and Bristol County Agricultural High School­—make smart decisions that reduced energy and water use and enhanced learning while supporting the health and wellbeing of all users. Each school had different reasons for choosing green roofs.

Saugus Middle High School in Saugus, Mass., sited less than 300 feet from a busy six-lane highway, supports progressive education in grades 6 to 12 and celebrates the town’s rich history of innovation. The $160.7-million school brings together 1,360 students in a 271,000-square-foot, STEAM-driven complex outfitted for exploratory learning and innovation.

Inspired by the Saugus River’s fundamental role in the town’s history, the new school incorporates multiple water conservation strategies. A stormwater collection and reuse system combined with the green roof slows stormwater runoff, saving more than 1.5 million gallons of water annually and leading to Saugus becoming the first project state-funded to reach the highest level of LEED certification, Platinum. In tandem with the environmental benefits, the 12,700-square-foot third-floor green roof provides program space for science curriculum-based learning, yoga, and mindfulness classes. The roofscape is centrally located and easily accessed by students and faculty. The exterior door to the outdoor classroom is also adjacent to the third-floor classroom devoted to medically fragile students, offering chose with limited mobility more opportunity to be outdoors.

Currently under construction, the $146.8-million Josiah Quincy Upper School in Boston is a 175,000-square-foot, six­-story facility char will accommodate 650 students in grades 6 through 12 when it opens for the 2024-2025 academic year. The location of the one-acre site, near the intersection of the Massachusetts Turnpike (I-90) and I-93, presented a different type of challenge than Saugus or Bristol Aggie. Combined, the two highways carry about 300,000 vehicles per weekday through the city, resulting in transportation-related air pollution.

During the design process, the project ream and stakeholders placed a high priority on fitting a robust educational program on a small, urban site and creating spaces that advance health, wellbeing, and equity. Because no other outdoor space was possible on the site, a large portion of the roof will serve as an outdoor classroom and physical activity area featuring walking paths and native species gardens. An added benefit of the roof garden is the access to fresher air high above street level, while the plants also actively remove pollutants from the air. Based on the area of vegetation and native plantings, the green roof project will achieve a credit in LEED for restoring natural habitat. Planned PV canopies have been deleted due to budget constraints bur are possible to add back if funds become available.

While every green roof is unique to its intended purpose, size, local climate, budget, and maintenance constraints, successful installations are usually the product of an interdisciplinary team effort by an architect; structural, civil (for stormwater), and mechanical/electrical/plumbing engineers; landscape archi­tect; botanist; and possibly irrigation specialist. State and mu­nicipal agencies can be important allies because of the overlap­ping trades involved and as more political advocates press for features such as this to increase climate resiliency.

Green roofs provide many benefits, from increasing a roofs lifespan, promoting biodiversity, and improving building energy performance to improving the efficiency of solar photovoltaic systems. While directly benefitting the school community, green roofs are also benefitting the broader community by cooling the immediate environment and reducing storm water runoff. Designing green roofs for schools offers even more opportunity: they can enhance the learning experience, improve health and wellness, and connect with a school’s curriculum and program goals.