Going Soilless and Low Maintenance in Singapore
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Urbanization has brought about both opportunities and challenges for city planning and development. One of the most innovative solutions to address these challenges is the purposeful integration of green roofs. This approach has gained attention worldwide due to its potential to harmonize urban living with nature, just like the Bidadari Park Toilet Project, completed by Singapore’s GWS Living Art. In this article, we will explore the concept of soilless green roofs and how they can transform urban environments, reduce disturbances to surrounding areas, and introduce a novel approach using their soilless technology with soft weed vegetation.
Ageratum conyzoides planted on Soilless Green Roof at the Bidadari Park. Source: GWS
Addressing Urban Disturbances with Green Roofs
Urban development often leads to disturbances in the natural environment, from increased noise pollution to reduced green spaces. However, the implementation of green roofs can mitigate these disruptions significantly.
One of the most remarkable contributions of green roofs to urban environments is the enhancement of biodiversity. In the bustling cityscape of Singapore, green roofs offer a unique opportunity to provide habitat for local fauna and insects by creating pockets of greenery and habitat in urban developed areas.
The tropical climate of Singapore brings with it the challenge of urban heat islands, places where urban areas are significantly warmer than their surrounding regions. Green roofs play a crucial role in combating this issue by providing natural insulation, evapotranspiration and shade through vegetation. With lower urban temperatures, green roofs also reduce the demand for air conditioning, which not only benefits energy conservation but also further mitigates the urban heat island effect by reducing the discharge of hot air from the building.
Finally, green roofs serve as natural sound absorbers, minimizing the environmental impact of buildings by reducing noise pollution. In densely populated urban areas like Singapore, noise pollution can be a significant concern, affecting the well-being of residents, especially during construction. The sound-absorbing properties of green roofs help create a more peaceful and serene urban environment and contribute to human health.
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Exemplifying Purposeful Integration: The Bidadari Park Toilet Project
The Bidadari Park Toilet Project in Singapore serves as a noteworthy example of how thoughtful integration of green roofs can enhance urban spaces. Located in the ecologically-sensitive regional park at the heart of Bidadari Estate, where residents can immerse themselves in nature, this project ingeniously incorporates a toilet facility within a lush green environment. The result is a harmonious coexistence of urban infrastructure and nature. This concept highlights the importance of minimizing disturbances to surrounding areas during urban development. In order to offset carbon emissions as soon as possible, the green roof was constructed first before the rest of the estate.
When plants were first established on the restroom facilities in the Badadari Park, Singapore. Source: GWS
Plants after growing for several months. Source: GWS
Going Soilless: GaiaMat™
Traditionally, green roofs are built with a soil substrate to support the growth of a variety of plants. However, a novel approach is gaining traction in Singapore – the use of soilless green roofs. GWS Living Art has patented their very own GaiaMat™, which they implement in most of their projects, including the Bidadari Park Toilet Project.
GWS Living Art’s GaiaMat™ soilless approach offers several advantages. GaiaMat™ is 2-3 times lighter than conventional systems, weighing between 5lbs/ft2 to 12 lbs/ft2, making them suitable for retrofitting existing buildings without the need for extensive structural modifications.
GWS Living Art’s GaiaMat™ system. Source: GWS
Worker harvesting plants from surroundings in Bidadari Park to transfer to the roof. Source: GWS
The emergence of soilless green roofs using soft weed vegetation (perennial herbs) represents an exciting leap forward in sustainable urban development. This approach not only conserves resources but also enhances urban biodiversity and contributes to a healthier, more sustainable urban environment.
As the vegetation is pregrown off-site, this approach has minimal irrigation with no fertilizers. Moreover, the absence of soil eliminates the risk of soil-borne pests and reduces the overall load on the building.
Soft Weed Vegetation
The incorporation of soft weed vegetation on green roofs introduces a paradigm shift in the conventional notions of aesthetics in urban landscaping. While the concept may challenge the preference for manicured, well-tended green spaces, it brings a host of benefits that contribute to more sustainable and resilient urban environments. The design of Bidadari Park was envisioned to draw on Bidadari’s history, and preserve the social memories and ecological importance of the site. We believe that the utilisation of the site's indigenous plant life harmoniously aligns with this vision.
One of the most compelling advantages of using soft weed vegetation is the utilization of existing flora from the local environment. In the case of the Bidadari Park Toilet Project, the park already hosts a diverse array of plant species that have adapted to the climate and conditions. Naturalized native weed species like Ageratum conyzoides – despite being commonly categorized as "weeds," merit a closer look. In truth, the label "weed" is ascribed based on the context – a plant becomes a weed when it is considered undesirable in a specific environment. Rather than importing a new set of plants, which can be resource-intensive and disrupt the natural balance, the existing vegetation in the park was harvested and seamlessly transferred to the green roof. The carbon footprint of the project is significantly reduced as there is no need for additional transportation of new plants to the site.
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Bidens alba planted on Soilless Green Roof at Bidadari Park. Source: GWS
Secondly, the question arises: Is there a need for a manicured roof in the first place? In many urban environments, the desire for perfectly manicured green spaces has led to higher maintenance costs, more frequent irrigation, and the extensive use of fertilizers. This traditional approach can often be at odds with the principles of sustainability and eco-friendliness, not to mention the economic burden it places on the building owners. By introducing soft weed vegetation, an extensive green roof can help owners break free from the maintenance-intensive aesthetics of conventional landscaping.
Lastly, certain soft weed species, like the Crotalaria retusa, exemplify the advantages of this approach. Crotalaria retusa is a plant that bears fruit and subsequently dies off, only to regrow naturally. This characteristic makes it a prime candidate for green roofs, as it requires minimal maintenance and intervention. By planting species with such characteristics, the need for frequent upkeep, pruning, and replacement is significantly reduced. In the tropical climate of Singapore, soft weed species are well-suited to the local weather conditions, further enhancing their sustainability. These plants thrive in the heat and humidity, requiring little irrigation and maintenance.
Crotalaria retusa is a low maintenance, flowering perennial plant used on green roofs in Singapore. Source: GWS
Conclusion
As urban areas continue to grow and evolve, the importance of low maintenance, low weight green roofs systems as demonstrated by projects like the Bidadari Park Toilet Project, cannot be overstated. Green roofs stand as a multifaceted solution to the myriad challenges urbanization imposes on cities. They are not mere ornamental additions but dynamic ecosystems with the capacity to enhance urban living in myriad ways.
The harmonious coexistence of urban living and the natural world is not just a vision but a reality in Singapore. It's a testament to the transformative power of green roofs, and other forms of greenery that are propelling us toward a future where every city can embrace and celebrate its green infrastructure potential, offering a breath of fresh air amid the urban hustle and bustle.
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Sylvia Toh, Design & Development Manager, Civil based at GWS Living Art.
Conan Gan, Marketing Executive at GWS Living Art, hello@gwslivingart.com
Zac Toh, Founder & CEO at GWS Living Art.
Design Team
Lead Consultant: CPG Corporation
Landscape Consultant: Henning Larsen
GWS Living Art specializes in urban green technology, turnkey development, and implementation of nature-based solutions, including green wall systems and green roofs. Based in Singapore – and have a regional presence in Asia, with projects spanning China, Taiwan, Thailand, Malaysia and Singapore.
For more information on this innovative approach to implementing super lightweight green roofs go to: www.gwslivingart.com
