Technological greenery between secular traditions, new technologies and formal research

Author: Arch. Edoardo Bit

1. Introduction

Italy can boast of a strong tradition in the field of integrating building systems and living vegetal organisms. Since ancient times our country has been able to provide historical examples of the techniques known today as "roof garden" - concerning the integration of plant systems and roofs, feasible or otherwise - and "vertical greenery", i.e. the placement of plants on facades with the relative biological devices. Two cases that come immediately to mind are the famous Torre Guinigi in Lucca (Fig.1), and the pergolas and facades covered with climbing plants that can still be seen in the historical fabric of Rome (Fig.2).

So, by giving well-known examples and historical techniques, the aim of this article is to analyse the progress of these methods in recent years.

Picture 1. Lucca, Torre Giunigi: view. Historical example of a roof garden, dating from the fourteenth century. There are also some holm oaks on the accessible roof of the tower.

 

Picture 2. Rome's historic centre: basic construction. The building is covered by a large vine, which spread autonomously several decades ago. (© Edoardo Bit)

2. Product innovation and technical standards

If the intensive design research under way involves a continuous implementation of technological systems for the roof garden and vertical greenery, the national situation is also characterised by important legislative and standardisation activity. Italy was, in fact, the first European country to give rise to a technical standard directed solely at roof gardens (namely UNI 11235: 2007, entitled Criteria For Design, Execution, Testing And Maintenance Of Roof Gardens), while, from a parliamentary viewpoint, it is worth remembering that in the recent Law 10/2013, Rules for the development of urban green spaces, Article 6 of the legislation is specifically aimed at describing the different forms of technical greenery existing today, as well as connecting to specific climatological and environmental benefits of their use.

Placing the accent on existing architecture, however, much has been done in recent years in the context of integrating plants into the design. If roof garden technology is now truly established globally (for example, two recent and important projects like the Vulcano Buono shopping mall in Nola, by Renzo Piano Building Workshop (Fig.3), and the new hospital in Mestre (Fig.4) by Emilio Ambasz & Associates), it is more interesting, in this article, to focus on the level of refinement achieved by the green wall.

Picture 3. Renzo Piano Building Workshop, Vulcano Buono, Nola (in the background).

Picture  4. Emilio Ambasz & Associates, Ospedale dell'Angelo Mestre: the project features a wide-ranging implementation of varying roof garden systems using diverse technologies. The healthcare facilities are below the grass in the foreground. (© Edoardo Bit)

There has been a sharp increase in experiments related to the theme of the green façade in the last decade, within the national borders, affecting all the various systems currently known. The vertical garden may in fact be based on the simpler and historicized matrix of "plant coverings ", or on more refined practices from a construction and systems point of view, like the technique of "vertical vegetative enclosures", brought into vogue in recent decades, on a worldwide level, by the Mur Végétal patent of the French botanist Patrick Blanc.

 

3. Green coverings and vertical vegetative enclosures

 

The plant covering is a low-tech methodology based on traditional agro-technical techniques: it involves climbing plants arranged in natural soil or in pots at high altitude, which grow vertically spreading along specific substructures (Fig.5). Another fundamental peculiarity of green coverings is that they are, since they are able to use not only evergreen plants but also deciduous plants, which are optimal for integration into transparent windows or continuous glazed walls, as a sun protection system (Fig.6).

Picture 5. Act_romegialli, Green Box, CeRiDo, 2011: building renovation based on the green covering technique. (© Marcello Mariana)

Picture  6. Arnold Gapp, multipurpose building, Marlengo, 2009: A large transparent facade of the library is protected from direct sunlight by vegetative covering, planted in pots. (© Edoardo Bit)

The vertical vegetative enclosing is, on the other hand, an extremely sophisticated technique from a technological point of view, as well as being based on advanced cultivation practices: soil-less systems, hydroponics etc. The vertical vegetative enclosures are made, unlike the previous case, with the system directly on the surface of the construction boundary (arriving at incorporating up to 60-90 plants per square metre), which is why these systems can only be used with evergreen flora and not climbing plants. In Italy there are several installations of vertical vegetative enclosures, from the 1990s on, when Renzo Piano hosted one of the first works of Patrick Blanc in the Genoa Aquarium project.

To date, in Italy, there are two main areas of use for the vegetative enclosing technology, which vary according to the environment of use: indoors or outdoors. The indoor vertical greenery is certainly the most widespread: in addition to considering flora basically as a furnishing accessory, like other noble materials (e.g. marble and granite), it also allows it to be used on smaller surfaces, and is therefore cheaper (Fig.7).

Picture 7. Studio Ricatti, Diesel Headquarter, Breganze (Vicenza): example of a vegetated enclosure in a confined environmental system.

Examining, however, the outdoor installations, the cases, although not many, are all of great value. The green facade of the Fiordaliso Shopping Centre (Fig.8) in Rozzano near Milan, designed by the architect Francesco Bollani, is still today the largest vertical vegetative enclosure in Europe, measuring 1,230 m2. Another much smaller dimensions but equally interesting case is the Trussardi Café in Milan, designed by Carlorattiassociati Srl, a design company run by the architect Walter Nicolino and the engineer Carlo Ratti (Figs.9-10). The Trussardi Café is an architectural gem located in the heart of Milan and, in addition to the multiple plant species of the system (i.e. composed of multiple types of plants at the same time), stands out also because the outer vertical green surface is perfectly mirrored within the building.

Picture 8. Francesco Bollani for Sviluppo Srl, Fiordaliso Shopping Centre, Rozzano, 2011. (© Francesco Bollani)

Picture 9. Carlorattiassociati Srl, Trussardi Café, Milan, 2008: night view outside. The technique used is the Mur Végétal, patented by the Frenchman Patrick Blanc. (© Armin Linke)

Picture 10. Carlorattiassociati Srl, Trussardi Café. View of the interior spaces, characterised by multiple species of plants, like the outside. (© Max Tomasinelli

4. Technological greenery for the reforestation of the anthropogenic environment

Continuing the theme of striving for maximum design hybridization between nature and architecture, another interesting phenomenon of recent times concerns experiments related to the use of technological greenery for urban reforestation.

The territorial expansion of towns and cities results, on the one hand, results in the consumption of land, and on the other the constant decrease in the presence of greenery in urban areas; a reason why those architectural experiments which consider the building itself as a potential factor for reintroducing plants into the city are getting a great deal of attention, where all possible surfaces of the building, containing various kinds of green systems (hanging, vertical, plants at an altitude etc.), become elements aimed at promoting urban biodiversity and the vegetal resilience of the anthropic space. In this regard, two examples, which are far apart conceptually but close formally, are the Vertical Forest in Milan, designed by Stefano Boeri (Fig.11), and the building 25 Green by Luciano Pia in Turin (Fig.12).

Picture 11. Stefano Boeri Architects, Vertical Forest, Milan, 2014: view of one of the two skyscrapers. Using altogether simple techniques (small roof garden surfaces and tree specimens arranged in high-rise flower beds), an extremely contemporary architectural look is obtained: the photo dates back to 2013, when the building was still under construction. In 2014 the Vertical Forest won the "International High-rise Award" that, every two years, identifies the most innovative skyscraper in the world. (© Edoardo Bit)

Picture 12. Luciano Pia, 25 Green, Turin. The design conception is substantially similar to that of the previous one, although the resulting form is very different. Also in this case the architectural image is characterised by a broad use of roof gardens and trees arranged in vases. (© Beppe Giardino

5.Towards Expo 2015: technical green for agricultural production

For the reasons set out so far, it is more than evident how important our country was in the past, and still is, in one of the most flourishing areas of experimentation for contemporary architecture, namely that aimed at the maximum interpenetration possible between building space and natural vegetation. And this has more value when you consider that 2015 is the year of the Expo for Italy. And therefore, as is the tradition, the World Fair will be the place to test and see, through the various morphologies and construction technologies of the pavilions of the various countries, what the most important design experiments now in place are on a global level - most of which provide an enhanced use of green facades and roofing (Fig.13).

Picture 13. James Biber, United States of America Pavilion at the Milan Expo 2015: rendering. The large multi-species green facade of the project winner of the international competition hosts vegetable plants (© James Biber).

At the Milan Expo site, from May to October 2015, the most innovative forms of technological greenery in architecture will be on display, with another point of interest regarding the analysis of the new specific function of the system itself. Many of the green sheaths at the exhibition area of Rho, in line with what the main theme of Expo 2015 is (Feeding the Planet, Energy for Life), will not just be purely ornamental or of a solely landscape value, but will have an agricultural function, aimed at the production of edible plants within the boundaries of cities and towns.

 

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