By Linda S. Velazquez, ASLA, GRP, LEED AP | Greenroofs.com | Publisher & Design Consultant | Esteemed Guest Blogger for Expotrade Middle East.
Imagine Dubai and the MENA (Middle East and North Africa) region’s hot, barren roofs and façades helping to cool the desert environment by sprouting to life with building integrated greenery. A mirage?
Not at all. Despite its harsh climate, the proverbial asphalt jungle – or more aptly the concrete jungle in the Middle East – can be enhanced with vegetation on roofs and walls when you take some key points into consideration!
Organic Greenroof & Greenwall Architecture Offers Sustainable Design for the New Millennium and Beyond
Green design practices promoting sustainable technologies increasingly have become major international architectural influences across the planet. The influence of rigorous benchmarking programs such as BREEAM, Leadership in Energy and Environmental Design (LEED®), BCA Green Mark Scheme, the Sustainable Sites Initiative™ (SITES™), and more recently the Living Building ChallengeSM and Estimada, has led to growing media interest and demand from public and private sectors for a new greater green ideal of designing with nature. Truly now ensconced within the architecture and construction sectors, high performance buildings and green infrastructure are set as green building standards of development.
Greenroofs are a form of low impact development (LID) and mitigate the negative effects of a building’s footprint by somewhat recreating the lost greenspace at roof level. And greenwalls also add nature, beauty, and function to a building. Numerous ecological, economic, aesthetic and psychological advantages include: stormwater management; extending the life of the roof to 40 – 75+ years; creating new real estate and increasing property values; filtering air, binding dust particles, absorbing CO2 and other pollutants, and lowering ambient temperatures thereby lowering the urban heat island effect; reducing both heating and cooling energy consumption and costs; creating habitat for displaced flora and fauna; providing acoustical insulation, noise suppression, and glare reduction; and even marketing and goodwill benefits.
Greenroofs & Walls: A Primer
Greenroofs and greenwalls are living, breathing systems and each project must be addressed with a variety of application possibilities, limitations, functionality and aesthetics. They have been around in various forms since the fabled Hanging Gardens of Babylon through Scandinavian sod homes, to the elaborate New York City Rockefeller Center Roof Gardens built in the 1930’s to Hundertwasser’s colorful apartment blocks in Vienna and Germany with undulating floors and vegetated roofs and walls from the late 20th century. The birthplace of modern day greenroof technology is Germany, where these engineered systems were developed and have been tested since the 1970’s, and where there is a lot of government support, too.
These engineered vegetated roof covers consist of layered systems of materials engineered to keep the roof watertight and create an environment for plants to thrive, and can be built in place or modular. The number of layers and the layer placement vary, but at the very least all greenroofs include: a single to multi-ply root-repellent waterproofing layer covering the roof deck, drainage, a filter fabric, growing media or the engineered soil, and the most exciting part, the plants. Although a building may be constructed with a variety, there are three main types, defined by the depth of the growing medium: Extensive (up to 5 or 6” approximately 13 – 15 cm), Semi-Intensive (8-12” or 20 – 30 cm), and Intensive (12” or 30 cm and above).
The term “greenwall” pertains to a variety of vegetated wall types. Broken down into Living Walls (part of a building envelope system, these are pre-vegetated or planted on site modules or panels containing plants, growing medium or hydroponic liquid installed in or on a frame, secured to a structural wall, or free standing) and Vegetated Façades (a training structure supports vines or climbing plants growing upward from the ground off the building). Both have a variety of mounting procedures and structural requirements.
Global Trends & New Technologies
Since 2007 Greenroofs.com’s Design Editor, Haven Kiers, and I have been compiling and presenting our annual “Top 10 List of Hot Trends in Greenroof & Greenwall Design” and we address what directions are sweeping our profession, what are a client’s motivating factors, how designers are pushing the limits, and what areas of the world are setting standards and becoming trendsetters. The influence of online and social media to promote living architecture is here to stay, and here are some more of the most popular trends that are sure to remain:
Passive Design & Cybertecture; Greenroofs Plus Solar Panels; Net-Zero Water Approach; Green Affordable Housing; Green Collar Jobs; Therapeutic Greenroofs & Walls as Horticultural Therapy; Biomimicry ; Green Inside and Out; Eco-Cities and Mega Developments; Rooftop & Vertical Farming; and Bioclimatic Skyscrapers.
Challenges Faced in MENA Climates
Razzle-dazzle aside, impervious cover has become a function of contemporary land uses. As a result of new land use practices in highly developed areas in non-arid areas of the world, we have over-stressed sewer systems that at times cannot handle the sheer amount of excess stormwater runoff. Yet in the MENA region, stormwater management is certainly not the problem, but the exact opposite: management of water resources and water conservation. Can living roofs and walls be a sustainable option here given the need for irrigation and high maintenance? Of course they can – with the right materials and practices.
Aside from the extreme heat, wind exposure and humidity in the UAE, it is critical to identify design obstacles to overcome, and have the ability to use local resources like any global region. Since the local soils are basically sand and are low in nutrients and salt-heavy, “sweet soil” (a mixture of sand and organic matter such as coco husk) is the soil choice at ground level. According to the president of Green Living Technologies International (GLTI), George Irwin, the problem for its use in living architecture is that it is also great drainage material, and lacking the necessary nutrient holding capability, it can be leached away through irrigation. Since a true deep microbial rich compost is not naturally occurring here, it is necessary to add some type in the growing media mixture. GLTi uses their own patented bioSoil.
In addition, there should be some water retention inherent in the system itself; for example, the GLTi greenroof system has a drain board and water retention mat combination with a high water holding capability. In fact, their greenroof system has been used as the base in the center areas of highways prior to the backfilling of sweet soil simply to retain irrigation water for the plants.
Having installed several greenroofs and walls in the area using a local nursery, George says there are hundreds of native and adaptive ground covers and grasses applicable to extensive roofs. But he advises to use nothing less than 6″ of growing media. Of course, it makes sense to use plants which thrive in the highly-saline maritime conditions, too. And since water is applied through irrigation, it must be applied efficiently. Greywater recycling programs should be investigated for maximum retention of the precious resource.
Another important piece of the puzzle is the physical structure itself. To avoid melting, any plastic components in the assembly have to be buried and cannot be unexposed. For greenwalls, plastic materials can fail time and time again; the heat in the UAE is simply too strong, breaking down the plastic very quickly. For this reason, stainless steel is often used in modular greenwall applications.
Due to the area’s infrequent rainfall, critical waterproofing skills necessary for a sound greenroof may be inadequate. Because the greenroof will receive regular irrigation, it is crucial to apply a quality single ply or a liquid applied membrane for waterproofing.
Finally, keep in mind the potential of renewable solar and wind energy to power the irrigation of the building integrated greenery.
Living Architecture in the MENA Region
Multidisciplinary professionals – from architects to engineers, city planners to landscape architects and beyond – are redefining sustainability in the context of building and environmental design. We’re examining our environmental impacts on the Earth from a more integrated, holistic approach and using technologies which encourage energy efficient and environmentally friendly building envelopes, including the ubiquitous “fifth façade” – the rooftop, and more recently the walls as well.
Continuing to advance a green economy with sustainable development is essential to our resource-constrained world. Using these wonderful examples of green leadership and living architecture as a basis for learning tools, design inspiration, and best practices, a great potential for further future robust eco-development is underway in the United
Arab Emirates and in many areas of the MENA region. The correct selection of materials, designers, and a firm maintenance plan are key to “greening” the harsh environs of the built desert, and making it a more ecologically smart landscape.
Linda S. Velazquez, ASLA, GRP, LEED AP, is founder and publisher/editor of Greenroofs.com (1999) where she writes and reports extensively about greenroofs and is principal of Sky Gardens
Design, a greenroof design and consulting firm. Linda holds a Bachelor’s of Landscape Architecture from the University of Georgia with honors (2000), is Member of the American Society of Landscape Architects, a LEED Accredited Professional, and an accredited Green Roof Professional. Linda is published as a collaborator in numerous
books and journals, magazines and online media. She speaks internationally at conferences around the world and develops and conducts presentations to groups and corporate clients. Linda’s role as Greenroofs.com Publisher and Editor allows her to write and film exclusive features, interview others, and collect project and market information from around the world, from public and private stakeholders, designers and students alike.
Greenroofs.com – Media Partners for Smart Landscape Summit 2014.
Founded in 1999, Greenroofs.com is is an internet news media organization: the international greenroof & greenwall industry’s open source resource and online information portal.