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Up on the roof

Antoine Gatt. Photo: Chris Sant Fournier

Antoine Gatt. Photo: Chris Sant Fournier

The LifeMedGreenRoof Project, set up within the Faculty for the Built Environment of the University of Malta, seeks to boost the eco credentials of our roofs, says project manager Antoine Gatt.

In recent years, we have seen an increase in the installation of photovoltaic panels. Does this show a shift towards a greener mentality?

There does seem to be an increase in green mentality and surely there is interest by a section of the population in green technology. However, the increase in photovoltaic panelsdoesn’t necessarily reflect an increase in green mentality: it just shows that the Maltese know their maths.

It pays to install photovoltaic panels and to shift towards sustainable practices. Creating a sustainable urban environment will benefit us greatly not only in terms of finances, as in the case of reducing energy bills, but also from a psychological and physical aspect. Increasing green infrastructure such as trees, public and private gardens, and green roofs in urban areas, will create more pleasing views and urban spaces, while increasing colour and seasonal interest which make the urban experience more pleasant.

Green infrastructure has the ability to enhance the quality of life in urban areas so it is a misfortune that we are still seeing gardens being destroyed to give way to higher density development for financial gain.

Having a green mentality means understanding the benefits that the natural environment provides with the consequence of moving towards integrating and protecting it. Moving towards sustainability requires a change in mentality in the way we do things and more social justice.

Despite this increase in photovoltaic panels installations, are local rooftops still underutilised?

In the past, rooftops were utilised for various domestic activities.People dried clothes, children played and others bred pigeons on the roof. There were those who socialised with their neighbours or slept on their roofs during the hot summer months. Unfortunately such activities have been greatly reduced due to a change in the way buildings are being constructed. The construction of penthouses has greatly reduced the living space on the roof.

In recent years, roofs have started being used to house photovoltaic panels. However such spaces can be utilised further for the advantage of residents and neighbours.

Roofs can take the place of the now rare private gardens. The technology exists to construct rooftop gardens very similar to those at ground level although some limitations exist depending whether the roof is being retrofitted or not. Green roofs – the technical term for such rooftop gardens – could be the answer many have been waiting for to enjoy a garden and grow anything from vegetables to flowers and trees.

Green roofs consist of spreading a growing medium, other than soil, over most or the entire roof area into which plants of various types can be grown. The types of plants grown depends on the depth of the growing medium which in turn depends on the structural integrity of thebuilding itself.

Green roofs provide a number of advantages to the owner and the community alike. They obviously provide amenity and recreational space and thermal insulation to the underlying rooms. They reduce the carbon footprint of buildings and energy bills and mitigate localised flooding as the growing medium absorbs a percentage of the rainfall and delays water run-off. Plants attract wildlife, which in turn provide ecosystem services. Green roofs also make photovoltaic panels more efficient by reducing the ambient temperature above the roof.

The LifeMedGreenRoof Project proposes a holistic approach, including insulation, the generation of alternative energy and the creation of wildlife habitat. Is such an approach affordable to all local households?

The installation of a green roof is not cheap and could be out of reach to some. However, the investment incurred will be repaid back in time, very similar to photovoltaic panels.

The LifeMedGreenRoof Project is in the process of constructing a demonstration green roof and the exact cost of construction will be known in the near future. The project also proposes the drafting of a document which will be presented to policymakers to highlight ways in which green roof technology could be widespread and rendered less of a financial burden. For instance, in other European countries we find financial incentives by local or central governments or legislation to encourage the use of green roof technology. Moreover, keep in mind that the installation of a green roof increases the value of one’s property.

The installation of a green roof increases the value of one’s property

The financial burden also relates to the type of green roof constructed. Green roofs are generally divided into two groups: intensive and extensive. The former have deep growing media and are very similar in aesthetic and practical aspects to the conventional ground floor gardens. Intensive green roofs require as much maintenance as ground floor gardens, although this also depends on the type of plants used.

On the other hand extensive green roofs have shallow growing media with low maintenance plants. Such extensive green roofs are constructed to provide effective insulation and improve the aesthetic characteristics of rooftops.

What are the main benefits of a green roof?

Modern green roofs were initially constructed for their aestheticappeal. They provide interest and colour. However in time people found that green roofs provide more benefits including the lowering of the urban air temperature which tends to be high (urban heat island phenomenon), and the lowering of the carbon footprint of buildings with the added bonus of lower energy bills. Green roofs also purify the air from airborne pollutants, muffle noise and provide psychological respite especially for the elderly.

Studies have also shown that green spaces increase the rate of recovery in convalescent people and help increase concentration in students. Efficiency in the workplace has also been observed due to the visual amenity.

In schools, green roofs can be used as educational tools whereas in the house they provide amenity space. Modern town planning has significantly reduced green spaces within urban areas, impacting negatively on the urban wildlife population. Green roofs provide a unique habitat for wildlife. The latter is important in providing ecosystem services. Think of the bees, which pollinate crops and flowers, geckos and bats, which consume hundreds of mosquitoes every night, or the bright colours of butterflies which capture our imagination and fascination.

How do green roofs enhance the urban aesthetic?

Aesthetics are as important in the creation of sustainable urban areas as other factors such as temperature control and flood mitigation. This is because humans rely heavily on sight and vision to carry out most daily activities. Vision also impacts on our psychological and emotional feelings. It is fair to say that aesthetics play an important role in our quality of life and well-being.

Whether green roofs are constructed for insulation purposes or as an amenity space, consideration has to be given to the aesthetic effect. The importance of aesthetics in human life should not be underestimated, as it gives meaning to our lives (Deep Ecology as an Aesthetic Movement, Environment Values 5, Tony Lynch, 1996). Thus by default, if green infrastructure ameliorates the aesthetic qualities of urban areas, then it positively contributes towards the quality of life.

The attractiveness of green roofs stems mainly from the fact that they provide interest and colour in the landscape. Gardens appeal to us because of their attractiveness and visual qualities (Creative Sustainable Gardening, Anthony D, 2000).

Green rooftop buildings serve solely as visual amenity to those neighbouring (overlooking) the edifice or who have direct access to the roof. If the edifice is a high rise building or an isolated one, then the benefits are very much reduced. Such benefits are only gained if the surrounding buildings are higher than the green roof itself as in the case of the Rockefeller Centre in New York or in a valley or lower altitude thanthe surrounding landscape, suchas Monaco.

The areas where the benefits of green roofs are mostly appreciated would be on the roofs of subterranean structures such as underground parking spaces and low buildings where the vegetationcan be observed in part or infull from road level or the surrounding buildings.

Considering that most of the new buildings being constructed are medium to high rise, then theinstallation of green roofs would benefit residents who would otherwise be overlooking bare, often black rooftops.

The LifeMedGreenRoof Project includes the installation of a green roof over the Faculty for the Built Environment. What challenges did this installation present?

Very little data is available on the performance of green roofs in the Mediterranean. Furthermore the Mediterranean environment is not one distinct climate but varies according to longitude, latitude and altitude. Milan, Malta and Tunisia are all Mediterranean, yet the climate varies considerably between one area and the other.

So, the first challenge we faced was the creation of two growing media specifically created for the local climatic conditions. Currently we are testing such substrates in 1m2 test trays. The tests being carried out at present relate to the ability of the growing media to support vegetation.

The second challenge is the choice of plants to grow on a green roof. Roofs have very particular microclimates: one of the project’s aims is to identify a number of native species of plants which are able to grow in a green roof environment. This is required to create low maintenance green roofs.

Apart from the plants’ resilience to climate, we have to consider also the aesthetic properties of the plants.

To date the tests being carried out are very positive and we hope to construct a demonstration green roof in the coming year.

Within the demonstration green roof, which will be open to the public, the roof will be planted with a variety of plants over and above those being currently tested.

The major challenge we face is convincing the authorities and the public of the benefits of green roofs and the installation of such technology nationwide over public, private and corporate buildings. Only by increasing the number of green roofs over a wide territory would major benefits be reaped.

What initial findings and data has this green roof generated?

Currently the findings generated relate to the creation of the green roof growing media and the choice of plants, and these to date seem very positive. However we still have another nine months of testing to carry out. Next year, after the construction of the demonstration green roof, we expect to carry out tests to prove the potential which green roofs have as insulation against heat especially in summer and the reduction of the use of air conditioning and the potential of green roofs at mitigating local flooding. We regularly post images on our Facebook page and update our website with the latest news and findings.

The green roof is also intended to act as a working demo. What ­interest has it generated from the commercial community and ­homeowners?

Many are those who appreciate the advantages of green roofs and are seeking more information about the progress of the project. Even considering that we are still in our early stages of research, we still meet with different stakeholders, including the general public, design sector and commercial community and discuss the benefits, advantages and challenges which green roofs pose. By so doing we are informing the public about this much needed technology, correct any misconceptions and we also learn about what such stakeholders feel are important issues with regards to the technology.

We have also published a short questionnaire on our website to learn more about people’s views on green infrastructure.

Who are your partners on the LifeMedGreenRoof Project and what added value to they give to the project?

There are four beneficiaries participating in this project, with the main beneficiary being the University of Malta. The other partners include the Malta Competition and Consumer Affairs Authority, Minoprio Analisi e Certificazioni and Fondazione Minoprio.

The partnership between the University of Malta, Minoprio Analisi e Certificazioni and Fondazione Minoprio is not coincidental. The Italian partners are strategically located and act as a hub of information due to their geographical location. Their proximity to centralEurope means that they inherit knowledge which is often inaccessible to Malta. Their expertise and experience will help the Maltese partners to carry out the relevant tests on substrate and vegetation and assist in the drafting of national guidelines.

Minoprio Analisi e Certificazioni, a member of Fondazione Minoprio, is a technical laboratory and research institute which collaborated with the Italian Green Roof Association in the drafting of the UNI Italian standards for green roofs. Furthermore Fondazione Minoprio and Minoprio Analisi e Certificazioni are working together with the Bolzano province, the Istituto Sperimentale di Laimburg and Casa Clima as a work group on Casa Verde - Gruens Haus, undertaking the responsibility and certification of green roofs and the refining of the Italian green roof standard. Thus their contribution in this project is valuable to the success of the project and the increase in knowledge on green roof techniques in the Maltese context.

On the other hand, the Malta Competition and Consumer Affairs Authority is a local public authority established in 2011 which amalgamated the Malta Standards Authority with the Consumer and Competition Department and Malta National Laboratory. Their experience in the drafting of standards is crucial when it comes to drafting of the green roof standard for Malta. Their experience and knowledge together with that of Minoprio Analisi e Certificazioni will help in the successful publication of a local green roof standard which will guarantee the proper construction of green roofs in the local context.

For more information about the LifeMedGreenRoof Project visit www.facebook.com/lifemedgreenroofproject and www.lifemedgreenroof.org or call on 2340 3621 during office hours.

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