Green spaces in buildings as a remedy for the negative effects of unsustainable urbanisation
Over the past few decades, the urbanisation process has raced ahead at a frantic pace, often unthinkingly and unsustainably, which has had its own impact on climate change. How is the rapid expansion of construction work affecting the management of natural resources in cities and the comfort of residents’ lives? How can green building contribute to improving local microclimates?
In the nineteen twenties, a man who is now one of the best-known names in world architecture published an essay in “L’Esprit Nouveau” (The New Spirit) magazine. The man was Le Corbusier and the essay set out his now famous five points of modern architecture. In line with his professed philosophy of design, which was grounded in three elements, namely, sun, space and greenery, he indicated a clear direction for contemporary building. The five assumptions he applied have remained an indicator of modernism in architecture to this day. They call for the use of a structure of columns to endow a building with a sense of lightness, horizontal, ribbon windows to increase the flow of natural light into the interior, the use of a ground plan freely designed without dividing the space into closed-off rooms, freely designed façades and flat roofs which can be transformed into green terraces and roof gardens.
The steady advance of urbanisation and the construction boom which have been observed over the course of the past few decades have brough negative consequences in their wake. As the land on which our cities and towns stand has been excessively concreted and tarmacked over, so the volume and speed of surface run-off has risen. This, in turn, overloads the sewage system and increases the risk of floods. At the same time, groundwater levels are diminishing without pause. All these factors are causing the deterioration not only of urban microclimates, but also the quality of residents’ lives.
One example of this would be the emergence of urban heat islands, which degrade the environment, impoverish cityscapes and result in significant rises in water and energy consumption during periods of drought. Further urbanisation leads to further concreting and tarmacking, driving the vicious circle of water management and flood prevention measures. The predicted increase in the extreme weather events such as long-term drought and violent precipitation, which are the consequence of global heating, will simply intensify these problems.
Returning to roofing roots
The notion of modern design which includes the provision of green spaces is clearly visible in twenty-first century commercial building. This is particularly true of the last decade, which has shown a consistent pursuit of ecological trends, with designers blazing the pro-climate trail. Alongside aesthetic and functional qualities, environmental and people friendliness have become the holy grail for contemporary architecture. Thanks to the growth of towns and cities along ecological lines, a new type of urban garden is emerging, in other words, the green roof. Green roofs crown modern properties, retaining rainfall, improving the microclimate, enhancing insulation and providing a home for bees.
Marta Weber-Siwirska, EngD, an assistant professor at the Wrocław University of Environmental and Life Sciences’ Institute of Landscape Architecture, president of the Polish Green Roofs Association and member of the Board of the World Green Infrastructure Network, provides some facts and figures:
The first green roofs came about when humans as a species left their caves and went wandering in search of food. What we’re talking about here are huts roofed and insulated with turf. (Nowadays), green roofs contribute to improving the local microclimate by mitigating the effect of urban heat islands. When the temperature is measured two metres above a green roof, it produces an average that’s around two degrees Celsius lower than for a traditional roof. In extreme cases, a roof with just a pitch covering can heat up to temperatures of eighty or even a hundred degrees Celsius, while the maximum temperature of a green roof will be between twenty-five and forty degrees, depending on what type it is. Green roofs also function as thermal isolation. The difference between the temperature in interior spaces under a green roof and those which aren’t can be as much as five degrees Celsius. This translates into economic benefits that spring from savings on air-conditioning or heating and can be calculated in concrete sums. Estimates put it at as much as nineteen per cent or more in a complete calculation of a building’s energy consumption. Green roofs can retain from fifteen to ninety per cent of rainwater. What’s more, the twenty-centimetre substrate layer muffles noise up to fifty decibels, which corresponds to normal office sounds.
The advantages of providing green roofs in building designs also include the fact that they help to ensure the biodiversity that conditions human life. The presence of plant life in human surroundings has a salutary effect on the quality of daily life in terms of producing oxygen and absorbing carbon dioxide. Not only that; their leaves also trap air pollutants in the form of dust. The calculation is a straightforward one; the more plants there are in our surroundings, the cleaner the air we breathe will be.
More than half the new buildings in Central and Eastern Europe to have received BREEAM and/or LEED certification of their ecological credentials are located in Poland. A great many of them have roofs, terraces or elevation walls designed to serve as green spaces. Most buildings of this type in Poland feature custom-designed aluminium systems.
The largest living wall in the country can be seen in the north-west, in the city of Szczecin. There, the Posejdon, Poland’s the first office and services building to have almost zero energy consumption, boasts a section of its elevation which has been converted into a fifteen-metre-high, vertical wall. Created on a single plane, it is a living wall measuring one hundred and fifty square metres. The structure, which is waterproof, fire-resistant and provides the right conditions for vegetation, has been planted with an astonishing six thousand, five hundred plants. The building, which has already received an international BREEAM certificate with a classification of ‘Excellent’, has a chance of elevating that to ‘Outstanding’ during the audit carried out as soon as it has been handed over. This is a major distinction for all the organisations engaged in working in the development, particularly given that an important part of it, the former Posejdon Center, is almost ninety years old.
The excellent results in terms of energy management were also possible thanks to the insulation, which was designed and made in line with the highest standards. One of the crucial elements contributing to the thermal insulation is the ALUPROF MB-SR50N HI+ façade system, with a structurally advanced thermal isolation zone. The use of aluminium profiles is what made it possible to bring all the elements of the historical part of the complex together in a striking composition with the glazed elevation above. The construction delineates new standards for the regeneration of much-loved buildings. Posejdon demonstrates that it can be done with respect for historical context and concern for the natural environment.
A gesture towards users and the environment
Another example of a modern property where the designers have provided its users with green space is ConcordiaDesign in Wrocław, in south-west Poland. Located on the city’s much-loved Wyspa Słodowa (Malt Island), it stands on the site of a four-storey apartment house which was built in 1845 and was the only building there not reduced entirely to rubble by the air raids of the Second World War. The challenge of restoring the historical remains and uniting them with the newly designed part while respecting all the relevant conservation and environmental standards, fell to a Dutch practice, MVRDV. Its architects managed splendidly! The developer’s main concept was to maintain the open nature of the island as it was and to build the Concordia Design community in symbiosis with the surroundings. One way in which this was achieved was by the use of sweeping glazing, which gives the impression that the boundaries between the interiors and the neighbouring edifice have dissolved. The fifth floor is the highest. It features an open terrace surrounded by an aluminium and glass balustrade, with views over the historical centre of the city spreading out below it. It is also home to Poland’s largest green wall. Measuring three hundred and sixty square metres, it contains ten thousand plants.
Michał Karbowiak, Community Manager for Concordia Design Wrocław smiles as he provides more details:
Actually, Concordia Design Wrocław has two green walls! The smaller one’s located in the co-working area. The larger one, on the roof terrace, is one of the largest in the country. It holds more than ten thousand plants and it’s a year-round, vertical garden. It’s a tourist attraction in itself alone. Our visitors are always amazed by it and love using it as a background for selfies that they then share on social media.
The building features state-of-the-art energy-saving solutions. The lighting is LED and its intensity can be controlled. There is a building management system and a heating system where the energy consumption can be adjusted to actual requirements. There is also aluminium joinery which was tailor-made for the building. The glazed walls were created using the ALUPROF MB-SR50N EFEKT semi-structural façade system, while the windows and doors were designed on the basis of the ALUPROF MB-86 SI system. Glazing was installed throughout the building’s façade and proved possible to use it in both the modern and restored, historical sections of the building, creating classic windows with glazing bars. Other strengths of the MB-86 include the excellent thermal insulation and high durability of the profiles, meaning that they lend themselves to creating large-scale, heavyweight structures while maintaining superb airtightness parameters.
A sprawling meadow at the heart of Silesia’s metropolis
One of the more interesting ways of using green space for a public building is the roof of MCK, the International Congress Centre in the southern Polish city of Katowice. It was built on the regenerated land of the former ‘Katowice’ mine and stands at the heart of a new district known as the Culture Zone, close to the famous Spodek sports arena, Muzeum Śląskie (the Silesian Museum) and the Polish National Radio and Symphony Orchestra building.
The green roof, which runs down to a grassy valley, has become one of the centre’s the leading features. The roof, which is now widely recognised, features a jagged, saw-toothed geometry with a span reaching up to thirty metres. The entire stretch is usable space intended to bear large loads, which constituted no easy construction task for the designers and contractors working on the building. The lower section of the roof, known as the Valley, runs diagonally to a path that residents and tourists can take from the square in front of the Spodek right up to the vicinity of the Polish National Radio and Symphony Orchestra building. There are also viewing points where visitors can admire the panorama of the Upper Silesian regional capital spread out before them.
The elevation is covered in a black, expanded metal mesh. This acts as a shade against excessive sunlight without limiting the views of the surroundings which are guaranteed by the plentiful glazing. The ALUPROF MB-SR50N mullion and transom system was used for the building, making it possible to create an aesthetic façade with visible, slender dividing lines and, at the same time, to ensure a solid, hard-wearing structure. The centre also features ta second ALUPROF solution, the MB-70HI window and door system, which guarantees excellent thermal and acoustic insulation parameters.
Green urbanity and urban greenery. The future for the building industry
Installing green roofs on newly constructed buildings and when an existing roof is being renovated is obligatory in numerous European towns and cities. In an era of climate change and the requirements introduced in a number of countries, green spaces are part of the definite and unavoidable future for the building industry.