Where will all Home Maintenance these people be accommodated then? How is the enormous energy demand of megacities covered? Will it be possible to reduce pollution and CO2 emissions? And what are the consequences of rising sea levels for densely populated coastal strips? Architects and urban planners are facing major challenges.Building in the sky
Early on, European cities had to struggle with space problems. Already in the Middle Ages there was not enough living space to accommodate all the newcomers who could no longer make a living in the countryside.
Medieval architects therefore tried to solve the problem by building upwards. The old town of the Scottish capital Edinburgh with its narrow skyscrapers is a well-preserved example of medieval urban development. But the material set limits for the architects for a long time.
Only with the inventions of steel skeleton construction and the electric elevator towards the end of the 19th century was it possible to build houses much higher. Completed in Chicago in 1885, the home insurance building with its ten floors and 42 meters height is considered the first modern skyscraper in the world.
Today, the tallest skyscraper in the world – the Burj Khalifa in Dubai – has more than 160 floors and is 828 meters high. But there are already plans to break through the magic one-kilometer mark.
However, such tall skyscrapers are primarily prestige objects for their builders and architects. As a concept for creating living space in cities in the future, they are only suitable to a limited extent. Construction and maintenance costs are far too high for this.
And yet, there are serious plans in Tokyo to build a “sky city” in a building large enough for 36,000 residents and 100,000 jobs.
On the whole, however, an opposite trend can be observed: height records are out in the construction of skyscrapers for residential purposes, while “green” and energy-efficient high-rise buildings are gaining in importance.
Building upwards is therefore only conditionally the solution for the future. At the same time, cities in the densely populated regions of Germany cannot grow endlessly in width.
The designation of new building areas on the edge of city and municipal boundaries also raises ecological concerns. The few remaining open spaces should rather be preserved as local recreation areas and green corridors.
That’s why the magic word in cities today is: “condense”. This principle provides for a much narrower development within the urban core zones. By making better use of the already fully developed, but not yet developed vacant lots and brownfields, additional required living space is to be created.
If an already developed area is expanded more densely – i.e. roads, sewerage, electricity, public transport are already available – the development becomes cheaper for the municipalities. Conurbations such as the Ruhr area or the metropolitan areas of Stuttgart and Munich already largely follow this principle.Bionics – nature as a model
However, it is not only new concepts for large-scale development that are being sought. New building materials are also on the rise. Here, scientists are increasingly consulting bionics. This branch of science takes nature as a model and tries to copy its mechanisms technically.
For example, scientists wanted to develop a material that was at least as stable, load-bearing and flexible as steel, but also many times lighter.
The result: the technical plant stalk. It was modeled after bamboo or horsetail. From a mechanical point of view, these plants are lightweight constructions that are surprisingly stable with their hollow stems and thin stalk walls, which they prove in the field under high wind loads.
The technical plant stem is braided and impregnated and also extremely light and durable. With its cavities, it is suitable for the construction of supporting structures in the architecture of the future.
The self-cleaning house façade paint is also a product of bionics. On lotus and kohlrabi leaves, it has been observed that dirt does not adhere to them.
When it rains, the leaf cleans itself automatically and thus always remains clean. Due to bulging cells on the surface, on which needle-shaped points grow again, water always rolls off.
But not only plants, but also animals serve as models for materials researchers, for example the fire beetle. He lays his eggs in burnt wood. To do this, he needs to know where there was a fire in the forest.
This, in turn, can be sensed to many thousands of meters with an infrared sensor. Scientists have discovered how the beetle sensor works and transferred this principle to a novel smoke detector. Energy and CO2 emissions
One of the biggest challenges for the future of housing is the question of energy consumption. The era of fossil fuels will come to an end sooner or later. At the same time, CO2 emissions must be drastically reduced worldwide.
The future of housing construction is therefore also about sustainable energy concepts and environmental protection. Houses have to drastically reduce their energy consumption, in the best case even produce energy.
New housing estates with so-called low-energy houses are springing up in Germany. Depending on the building regulations, these houses may only have a very low energy requirement for heating and hot water preparation. The savings potential is achieved above all through greatly improved thermal insulation.
The passive house, on the other hand, does not require any heating thanks to an optimised interplay of ventilation, thermal insulation and solar radiation on the windows and is regarded as a consistent further development of the low-energy house.
But it can be even better: The plus-energy house is no longer a vision of the future, but feasible. Here, the house, which is heated according to the same principle of the passive house, even becomes a power plant that feeds excess energy into the power grid.
The plus-energy house produces 100 percent renewable energy by means of solar collectors and heat storage and runs as an emission-free operation. And if too much electricity is produced, it can be sold to the local energy supplier. Innovative concepts and bold visions
Global climate change and growing poverty in Third World countries are also giving rise to new forms of construction. Some of them have already become reality, while others are still bold visions. Floating houses are already part of the repertoire of innovative architects.
The Dutch stand out in particular, looking for new ways to cope with the constant danger of flooding.
So they invented houses that are built almost directly on the water and can rise with the flood. Entire settlements have already sprung up in Leeuwarden, Maasbommel or in the Amsterdam district of Ijburg.
In the Third World, on the other hand, it is particularly important to keep a house as cost-effective as possible. After a party in the Honduran capital Tegucigalpa, for example, the German carpenter Andreas Froese thought about how to recycle all the discarded PET bottles.
Together with some residents, he systematically layered the bottles on top of each other, filled them with rubble and earth and bricked them up with mortar. The resulting house should even withstand medium-strong earthquakes and would perhaps be a construction concept for the future.
The German entrepreneur Gerd Niemöller has chosen another cheap material for building houses: paper.
In a special process, the plastic-coated paper walls are pressed into a honeycomb shape and are thus very stable. For the construction of a 34 square meter paper house with kitchen, bathroom and two bedrooms, only the wood of a tree would be needed.
In the future, the paper house is to shape the image of numerous slums in the Third World – at least that’s Niemöller’s vision.
However, at a price of about 4000 euros per house, this plan is quite absurd. Unless local governments get involved or there are enough aid organizations to solicit donations.