Living Architecture: Green Roofs and Walls

By Graeme Hopkins and Christine Goodwin

Extensively illustrated with photographs and drawings, Living Architecture highlights the most exciting green roof and living wall projects in Australia and New Zealand within an international context.

Cities around the world are becoming denser, with greater built form resulting in more hard surfaces and less green space, leaving little room for vegetation or habitat. One way of creating more natural environments within cities is to incorporate green roofs and walls in new buildings or to retrofit them in existing structures. This practice has long been established in Europe and elsewhere, and now Australia and New Zealand have begun to embrace it.

The installation of green roofs and walls has many benefits, including the management of stormwater and improved water quality by retaining and filtering rainwater through the plants’ soil and root uptake zone; reducing the ‘urban heat island effect’ in cities; increasing real estate values around green roofs and reducing energy consumption within the interior space by shading, insulation and reducing noise level from outside; and providing biodiversity opportunities via a vertical link between the roof and the ground.

This book will appeal to a wide range of readers, from students and practitioners of architecture, landscape architecture, urban planning and ecology, through to members of the community interested in how they can more effectively use the rooftops and walls of their homes or workplaces to increase green open space in the urban environment.

• Language: English
• Publisher: CSIRO PUBLISHING
• Release date: May 16, 2011
• ISBN: 9780643103085

Book preview

Preface

Our personal and professional interest in living architecture, green roofs and living walls has been nurtured over many years of living and working in a variety of Australian cities and regional areas. In our projects, we have responded to a range of climatic zones – from alpine to tropical, from cool temperate to semi arid lands – to focus on the integration of landscape and architecture to create a greener, more liveable environment. Green roofs and living walls have been a significant part of our work, long before the contemporary recognition of these terms, but this abiding interest has become a passion in recent years.

The turning point for Graeme Hopkins was when he was awarded a Churchill Fellowship in 2005 to travel overseas ‘to study the latest information, technology and projects featuring elements that make up a bushtop landscape (refers to the Australian bush or wilderness), which recreates particular ecosystems on the top of buildings and on vertical walls’ (Hopkins 2006). His travels took him to the USA and Canada, and then on to Japan, Singapore and Malaysia, where Christine Goodwin joined him for the second half of the study tour. Since then, we have devoted most of our professional activity to the promotion, development and implementation of green roofs and living walls, and this book marks a significant step along this journey.

We wish to thank the CSIRO for assisting us present the concept and practice of living architecture to the wider community, and we wish to express our gratitude to all those who so generously allowed us to include their research and projects. We hope that this book will inspire design professionals, developers, legislators and individual home owners to clothe their buildings in green and enjoy the benefits. Although we include specific projects to bring the text to life and to demonstrate the diversity of practice, this is not intended as a definitive survey of Australian and New Zealand green roofs and living walls. There are many more exciting and innovative projects out there, or on the drawing boards of many designers, so we urge readers to keep exploring the possibilities and to keep looking skywards.

Graeme Hopkins and Christine Goodwin

Fifth Creek Studio, Montacute, South Australia

CHAPTER 1

Context and classifications

It is generally accepted that Mayday, 23 May 2007 is the date that the global human population passed a significant milestone, when the number of people living in cities exceeded the rural population for the first time. A major feature of this demographic shift is that denser cities result in greater built form, with more hard surfaces and less green space, landscape areas and permeable surfaces. Even in Australian and New Zealand cities, where the average household has decreased from 5.3 to 2.6 people over the last 100 years, residential subdivision lot sizes are reducing dramatically, while the average physical size of individual dwellings is increasing, leaving little room for vegetation or habitat.

The demographics and lifestyles of the current generation are quite different to earlier generations, with people now marrying later, living longer and enjoying more cosmopolitan lifestyles. The environment of our cities has been adapted to these conditions with the provision of promenades, outdoor cafes, meeting places and entertainment areas, but this has put greater pressure on the natural environment, especially endemic ecosystems.

These dramatic changes in population densities and the urban environment are helping to fuel the unprecedented climate change currently taking place, while, in turn, the damaging impacts on the urban environment are being exacerbated by this climate change. The results of globally increasing temperatures, melting of the polar icecaps and rise in sea levels, among other devastating impacts, will be felt most severely in cities and urban areas, including those of Australia and New Zealand. The Garnaut Climate Change Review commissioned by the Australian Government in 2007 warned that ‘On a balance of probabilities, the failure of our generation on climate change mitigation would lead to consequences that would haunt humanity until the end of time’ (Garnaut Climate Change Review 2008). This warning still stands, despite the failure of nations to make any binding commitments at the Copenhagen Climate Summit in December 2009.

One way of creating more natural environment within cities and helping to mitigate climate change, as well as accommodating the other competing pressures for space, is to use the rooftops and vertical surfaces of buildings. Rooftop gardens or green roofs have been long established in Europe, and were more recently introduced to North America and Asian countries, such as Japan and Singapore. Australia and New Zealand have a relatively short history in this area, but are now embracing the move towards green roofs and walls and, while there are some climatic differences to consider, the technologies being developed in the southern hemisphere have particular relevance to northern hemisphere summers and to this time of globally changing climate.

A green roof replacing ground-level green space

The concept of green roofs is very simply illustrated by the diagram above, where the footprint of a building is replaced with a green roof, with no net loss of green open space or habitat. Living walls on the vertical surfaces of the building can further add to this positive environmental effect. Together, green roofs and walls create a living architecture, where the formerly inert built form of concrete, steel, timber and glass comes alive – breathing, cooling, cleansing and recycling.

Green roofs and living walls are, of course, not the only answer to all our environmental problems, but are part of a broader urban green infrastructure (instead of the usual engineered infrastructure) approach that integrates a range of methods and processes to address stormwater management, temperature control, pollution reduction, reclamation of urban wastelands, public health and lifestyle, and also provides a raft of economic benefits. Through carefully designed green infrastructure, we can create and modify microclimates within cities, making these environments more habitable to humans and other fauna and flora.

Later in this book, we examine the context of the living architecture of green roofs and walls within city-wide green infrastructure, but firstly we look directly at the rooftops and walls that surround us. We start with a brief historical perspective to provide some understanding of the origins of living architecture. We will consider green roofs within an international, and then Australian and New Zealand, context, followed by a similar appraisal of living walls. A brief summary of the terminology of green roofs and living walls follows.

International context of green roofs

The earliest references to green roofs relate to the Hanging Gardens of Babylon and other roof gardens on stone temples that were developed around 600 BC in Mesopotamia. These provided a green, cooling effect in the hot arid climate of the Middle East. In contrast, in cold northern Europe during the Viking era of around 800–1000 AD, sod roofs were implemented, where ‘turf, and occasionally seaweed, was used to line the walls and roofs of homes for protection from harsh winds, extreme cold, and rain’ (Peck 2008).

In the early 1900s, internationally influential architects Swiss-born Le Corbusier and American Frank Lloyd Wright included rooftop gardens and terraces in some of their projects, with particular emphasis on using these spaces as outdoor living rooms. For instance, Wright’s Larkin building in Buffalo of 1904 included a paved roof garden, and in 1930 Le Corbusier completed the Beistegui apartment in Paris, featuring a surrealist-inspired roof garden. Reference was made to this international architectural movement in Adelaide’s Advertiser newspaper on 13 April 1907, in an article titled ‘Flat roofs and roof gardens – a suggestion to Adelaide householders’. Several commercial roof gardens planned for Adelaide and a proposal for the City of Unley Town Hall were mentioned (Aitken 2009).

Between the World Wars, two international gardens stand out as particularly significant: the Derry and Toms Department Store roof garden in London and the Rockefeller Centre series of roof gardens in New York, which were completed in the mid 1930s (Osmundson 1999).

The Second World War saw a virtual halt to large-scale building projects, including any significant rooftop garden development, so it was not until the 1960s when there was a revival in the green roof industry. This was particularly evident in Germany, Switzerland, Austria and Norway, occurring as a counter to the decline of green space and the harshness of the urban environment.

The German green roof movement also led to the development of lightweight, extensive green roof systems during the 1970s-1980s. Formerly green roofs were mainly intensive, comprised of a relatively deep growing medium that supports high plant diversity, and requires regular maintenance. In contrast, extensive systems are low maintenance, being comprised of shallow, lightweight growing media suitable for tough, drought-tolerant plant species such as sedums.

Grin Grin horticultural complex, Fukuoka, Japan

Subaru’s Singapore headquarters 4WD testing track on rooftop

Arguably, North America has become as significant as Europe today in terms of implementation of green roofs, with cities including Toronto, Vancouver, Chicago, Boston, Portland, Phoenix, Washington DC and New York virtually exploding with a dazzling variety of projects. However, it is probably in Singapore and Japan that some of the most innovative and experimental projects are occurring, particularly in cities such as Tokyo, Kyoto, Osaka and Fukuoka.

In South Korea and China there are a number of new towns and eco-cities planned, incorporating green roofs as part of their focus on sustainability. For instance, a new multi-functional administrative city is being created in Korea, based on the visionary design by Balmori Associates and Haeahn Architecture. The design features an extensive series of interconnected green roofs as an integral part of the city master plan aiming to ‘merge together art, landscape, and form and ... create public spaces that allow people to interact with nature’ (Merkel 2007). Although such exciting developments point to a potential green roofs and walls super-movement in Asia, some projects have stalled because of unachievable timeframes and budgets. As climate change takes hold, and the need to mitigate the environmental problems of large cities becomes even more crucial, the expansion of the green roofs and living walls industry seems assured, albeit within a sustainable timeframe and context.

Australian and New Zealand context of green roofs

Australia and New Zealand have the advantage of an extensive body of worldwide research and project precedents to draw upon, plus the challenges of relatively small population and economic bases, in addition to specific climatic extremes that require some different approaches and solutions to those suitable for the northern hemisphere. Indeed, we need to look firstly within our own lands and histories to develop ideas and directions that have the most relevance for us.

In both Australia and New Zealand, settlement by the British occurred in relatively recent times, with Australia’s colonisation dating from 1788, and British sovereignty secured in Aotearoa New Zealand with the Treaty of Waitangi in 1840. The Australian Aborigines and the Maori – the original, traditional owners of each nation – have a history of using a wide range of natural resources within their respective, climate responsive, vernacular architectural practices. This includes employing techniques of cladding their timber or stone structures with thatched or woven vegetable materials. Although perhaps not strictly green roofs or living walls in the contemporary context discussed in this book, the basic principle of vegetation providing human shelter and comfort is instructive within our exploration of living architecture.

Contemporary green roofs did not make a sudden, dramatic appearance in Australia and New Zealand, but have evolved from a variety of earth-covered dwellings, roof gardens, and elevated podiums and terraces. Although we now make a distinction between earth-covered buildings and contemporary green roofed buildings, there are some similarities to be noted. Earth-covered structures range from those that are built entirely underground, such as the dugout dwellings and commercial premises developed since the early 1900s in response to extreme heat in the opal mining community of Coober Pedy in outback South Australia, to the 1970s-1980s resurgence and progression of ‘terratecture’ theory and construction of above-ground buildings that are waterproofed and then back filled. Examples of these latter earth-sheltered buildings are found in the Sydney region, particularly those designed by the architect and landscape architect Sydney Baggs, and architect David Baggs.

Coober Pedy underground house

Cherryville underground house

In the 1980s, an Australian franchise was taken up for the US-based Terra-Dome Corporation, with a number of concrete dome homes constructed, especially in rural Victoria. At Cherryville in the Adelaide Hills, a terra dome home constructed in the early 1980s remains a fine example. Also in South Australia, earth-sheltered houses designed by architect Pauline Hurren, and by building designer Paul Mitchell, might now be described as having green roofs. Earth-covered building technology shares many of the advantages of green roofs, such as temperature control, stormwater management and increased biodiversity opportunities, but the form of the structures is relatively restricted compared with the potential diversity of contemporary green roofed buildings.

The formation of Green Roofs Australia (now Australasia) in 2007, New Zealand’s Living Roofs in 2009 and the more recent formation of Green Infrastructure Network Australia, together with research undertaken by several Australian and New Zealand universities and a handful of commercial and private organisations, is spearheading a burgeoning of green roofs and walls within our cities and, interestingly, in environmentally sensitive environments such as national parks and scenic coastal locations. A brief survey of developmental green roofs in Australia and New Zealand will help to contextualise the current and future developments discussed in this book.

Readers Digest building, Surry Hills (1967)

This heritage-listed building was designed by architect John James, and was the first office in Sydney designed to house a computer system. The large rooftop garden by Bruce Mackenzie features tall trees such as native Acacia, Casuarina and Melaleuca in 2-m deep soil.

Art Gallery of New South Wales (1968–1970)

Designed as part of the Art Gallery redevelopment by architect Andrew Anderson, the elevated lawn over the Cahill Expressway provides a vista to Sydney Harbour as well as additional open space.

Adelaide Festival Centre (1973–1980)

Designed by Hassell Architects, this complex of buildings on the banks of the River Torrens in Adelaide, is linked at terrace level by elevated podium planting beds, public artworks and pedestrian access walkways, providing public open spaces to complement those at ground level below.

Capita Centre (now Castlereagh Centre) Sydney (1984–1989)

Harry Seidler and Associates designed this building with an internal light well/atrium that changes its orientation within the building to form ledges, which are planted with Sydney endemic plantings.

Detail of planting on Capita Centre, Sydney

Australian Parliament House (1988)

After a ‘temporary’ building served the Australian national parliament for more than 80 years, the design of the new permanent building by architects Mitchell, Giurgola and Thorp features large areas of lawn and detailed planting zones to encourage pedestrian access over the building, thus adding to the accessible open space. The building was opened on 9 May 1988 and continues to be considered an iconic national symbol.

Capital Centre Canberra roof gardens (1988)

Architect and landscape architect Graeme Hopkins designed and constructed a series of small landscape gardens that acted as rainwater detention basins on a high-rise building in Canberra. These gardens were designed to function without soil or vegetation because the structural design of the building did not allow for soil loadings. The use of pebbles in different colours and patterns created a dry watercourse effect. ‘The spaces between the pebbles were used as the detention factor, allowing water storage for a short time before being released into the stormwater system’ (Goodwin and Hopkins 2005). This project represents an early occurrence of water sensitive urban design (WSUD) on a building, rather than on the ground.

Tourist resorts of 1980s-1990s

From the 1980s, many tourist resorts and residential complexes were designed with rooftop gardens on podium levels as part of a tropical-inspired design style. One example is the 1989–1990 Sapphire Beachfront Apartments development at Coffs Harbour in New South Wales, where Graeme Hopkins designed and constructed landscape podiums and balconies using palms and plant communities that were growing on the site prior to the new development. These palms, trees and shrubs were relocated to a temporary nursery for 18 months and then planted within the building complex during construction. Plants were carefully chosen and used in the design to work with the building structure to create microclimates for courtyards, to deflect and alter wind turbulence around the buildings and to create a cooling effect for accommodation units. The plantings also play a role in absorbing the carbon dioxide and monoxide emitted by the three-storey car parks.

Parliament House, Canberra, where much of the functional building space is located under the extensive lawn

Rooftop pebble gardens on Capital Centre Canberra

Sapphire Beachfront Apartments multi-level rooftop gardens in Coffs Harbour

Tourist resorts and accommodation complexes such as the Sapphire example were to provide prototypes for the growing demand for green roofs on medium- to high-density residential buildings.

Woollahra Municipal Council (1997–2001)

Design firm Terragram, headed by Vladimir Sitta, undertook the redesign of the publicly accessible gardens and design of a new roof garden for the restored and upgraded Woollahra Municipal Council building on an historic site, as an integral part of the masterplan for the entire Redleaf area in Sydney’s eastern suburbs. The building redevelopment by architects Keith Cottier and Michael Heenan uses ecologically sustainable development (ESD) principles, including drawing air into the building through thermal chimneys that take advantage of the evaporative and cooling effects of the vegetation.

Roof garden of Woollahra Municipal Council (Vladimir Sitta)

The Conservatorium of Music is almost invisible below landscaped terracing

Sydney Conservatorium of Music (2001)

The 2001 redevelopment, incorporating an historic building by colonial architect Sir Francis Green-way, was completed by the NSW Government Architect Chris Johnson and the architectural practice of Daryl Jackson, Robin Dyke and Robert Tanner. Landscape architects Clouston Associates designed the roof garden/elevated podium to provide thematic and visual connections with the adjacent Royal Botanic Gardens.

Christie Walk Adelaide roof garden (2002)

Designed by Ecopolis Architects, this is a medium-density cooperative housing development that demonstrates the combination of ecologically sustainable and community enhancing features. It is a relatively early example of a community project strongly focused on sustainability, with a green roof as an integral part of its design, serving both as a recreation roof and a food-producing garden. There are now a number of more recent community based projects with green roofs. This project is examined in more detail later in the book.

Hocking Place Adelaide bushtop (2006)

The term ‘bushtop’ has been coined in reference to the Australian bush or wilderness. Designed by Fifth Creek Studio, the habitat of this bushtop green roof specifically targets certain bird species, and also provides the tenants of this public housing building with an aesthetically pleasing private recreational open space resource in the centre of the city. This project is also examined in more detail later.

NZI Centre

Although a very recently completed project (2009), this Auckland building designed by Jasmax Architects sets a precedent in New Zealand sustainable design, with the green roof contributing points towards the 5 Green Stars certification awarded by the New Zealand Green Building Council. The green roof helps to reduce stormwater runoff, with water being recycled for flushing toilets in the building.

Sod roof revival

Some of the formative green roof projects in New Zealand are based on the European tradition of sod roofs, with a 1960s-1970s mini-revival occurring mainly in the South Island, associated with concerns for more environmentally sustainable lifestyles and building practices.

Kawakawa public toilets

Also of special interest is the influence of the renowned Austrian artist and architect Frederick Hundertwasser, who spent the final 20 years of his life living in the North Island of New Zealand. His green roof public toilet block in Kawakawa has become a major tourist attraction and has also inspired a niche market for organic tiling (individual and organic style similar to the exuberant tiling style of Spanish architect Antoni Gaudi). Images of this extraordinary public facility are included in Chapter 4.

International context of living walls

The development of green or living walls can be traced back through a variety of vegetated shade devices designed to counter extreme climatic conditions in an aesthetically pleasing manner.

As with green roofs, the famous Hanging Gardens of Babylon mark an early point in this development and there are many other well documented examples through to the 17th century AD throughout the Mediterranean region. The Romans trained grape vines on garden trellises and on villa walls, and in Medieval castles secret gardens were concealed behind climbing roses.

Buildings dating from early European settlement in both Australia and New Zealand used the cooling effect of creepers growing on their facades, while fences and trellises have been used for fruit growing and decorative climbing plants to provide a functional and visual screening effect in suburban backyards for just as long. Contemporary green or living walls continue these benefits, along with the many additional benefits that are now recognised.

In the 1920s, the British and North American garden city movement promoted the integration of house and garden using features such as pergolas, trellises and self-clinging plants. By 1988, the introduction of stainless steel cable systems enabled more sophisticated design of green facades, and in the 1990s cables and wire-rope net systems and modular trellis panel systems entered the North American marketplace. The first application of a trellis panel system was in 1993 at Universal CityWalk in California, followed by the indoor living wall with biofiltration system installed in the Canada Life Building in Toronto in 1994.

In Zurich, Switzerland, the MFO Park with a multi-tiered park structure using 1300 climbing plants was constructed in 2002, providing a new interpretation of an urban park as a vertical, spatial and architectural green open space.

The Japanese government sponsored the massive Bio Lung exhibit at Expo 2005 in Aichi, which was comprised of 30 different modular green wall systems that were available in Japan at the time. The Japanese living wall industry continues to develop and expand.

Australian and New Zealand context of living walls

Given the current concern for environmental and urban ecology issues for the environment of our cities, there is a growing interest in how to green our cities