Page 42 - spaces4learning, Spring 2023

spaces4learning SUSTAINABILITY
GREEN ROOFS EXPAND MINDS AND OPPORTUNITIES
By Gary Brock
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 stone 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 to 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 Aalto, 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.
Myths and Benefits
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 contrac- tors 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.
Unique Schools, Unique Roofs
As a practitioner of sustainable design promoting the responsi- ble use and conservation of natural resources, HMFH has had opportunities to leverage this expertise by helping three Massa- chusetts 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 en-
42 SPRING 2023 | spaces4learning.com
RENDERING COURTESY OF HMFH ARCHITECTS