14.02.2026

Plan unsealing strategically – where, how much and with what effect?

Building design

Photograph of a German city from a bird's eye view by Markus Spiske, shot with a Canon 5d Mark III and Leica Summicron-R 2.0/50mm (1981).

Unsealing has long been more than just a fig leaf for the guilty conscience of urban societies. Unsealing surfaces not only makes them more beautiful, but also smarter – and creates measurable added value for the climate, cityscape, quality of life and biodiversity. But where, how much and with what effect? Strategic unsealing requires more than just spades and good intentions. It’s about data-based prioritization, innovative methods and a deep understanding of urban dynamics. Welcome to the supreme discipline of sustainable urban development – skillful restoration.

Why unsealing is indispensable from an ecological, urban climate and social perspective.
How a strategic approach maximizes the effects of unsealing.
Which planning tools and data-based methods enable the prioritization of suitable areas.
How much unsealing is required to achieve relevant effects – and how these effects can be made measurable.
Innovative implementation examples from Germany, Austria and Switzerland.
Typical stumbling blocks: legal, economic and cultural hurdles.
Long-term monitoring strategies and the role of participatory approaches.
A look into the future: how digitalization and urban data are revolutionizing unsealing.
Conclusion: Why unsealing must be part of the DNA of sustainable urban development – and how it can become a model for success.

Unsealing as a strategic task: from a compulsory exercise to a driver of transformation

When people talk about unsealing today, they often think of small urban garden projects, breaking up a parking lot or removing paving stones in the backyard. But in fact, the topic has become a highly relevant component of sustainable urban development in recent years. The reasons are obvious: sealed surfaces exacerbate urban heat islands, prevent water infiltration, promote flooding and destroy habitats. In view of increasingly extreme weather conditions, growing cities and a growing social awareness of climate adaptation, the question of targeted reclamation of open spaces is becoming a strategic focus.

This means that unsealing is no longer an optional extra, but a mandatory task that goes far beyond the symbolic. Cities and municipalities are under pressure to reduce land consumption and use existing areas more sustainably. At the same time, funding programs, European climate targets and national sustainability strategies demand measurable progress. This is leading to a remarkable dynamic: unsealing is becoming a touchstone for the innovative strength and future viability of municipalities, planning offices and landscape architects.

Unlike traditional green space projects, unsealing involves the deliberate dismantling of existing structures. This means removing paved surfaces – from asphalt to concrete to paving – revitalizing the soil and enabling new, multifunctional uses. This includes not only parks and meadows, but also urban gardens, rainwater management areas, temporary cultural venues and new mobility spaces. The trick is to turn an apparent weakness – too much concrete – into a strength: more quality of life, more resilience, more urban diversity.

However, if you want to strategically unseal, you have to think big. It is not enough to act selectively or focus on individual projects. Rather, an integrated approach is needed that involves different specialist disciplines, administrative areas and civil society. Unsealing is therefore a classic cross-cutting issue that affects planning, the environment, mobility, water management, social affairs and the economy in equal measure. The challenge: How can this balancing act be mastered in practice? And how can planning instruments, digital tools and participatory processes help to turn unsealing from a niche project into a driver of comprehensive urban transformation?

The change is tangible. More and more municipalities are setting themselves binding unsealing targets. Funding programs such as the federal program “Measures to adapt to climate change” or state initiatives in Bavaria and North Rhine-Westphalia are picking up speed. At the same time, new alliances are emerging between environmental associations, citizens’ initiatives, companies and city councils. The goal: to understand unsealing as a strategic task, to achieve measurable effects and to dare to be truly innovative. Those who act now will shape the city of tomorrow – and secure themselves a place in the Champions League of urban development.

Where and how much to unseal? Data-based prioritization in complex urban spaces

The key question of unsealing: Where does it have the greatest effect? And how much must be removed in order to achieve tangible improvements for the climate, biodiversity and quality of life? The answer lies in the triad of analysis, prioritization and impact monitoring. Modern urban planning no longer relies on gut feeling or political expediency, but on an increasingly sophisticated database. In particular, geographic information systems (GIS), digital city models and urban data platforms are opening up new possibilities for analyzing areas, creating scenarios and monitoring success.

The first step is to precisely record the extent of sealing. Satellite data, drone flights, cadastral information and soil samples are combined for this purpose. This creates a differentiated picture of the surfaces: from completely sealed traffic areas to partially sealed inner courtyards and unused fallow land. It is crucial to differentiate between areas that can be technically unsealed (e.g. parking lots, abandoned railway tracks) and those that are out of the question for functional or legal reasons (e.g. critical infrastructure, listed buildings).

A central tool is the overlaying of sealing maps with urban climate data. Where do heat islands occur? Where are fresh air corridors or infiltration areas missing? Where are the risks of flooding highest? By combining this with population data, mobility flows and social indicators, so-called hotspots can be identified – i.e. places where unsealing promises particularly high ecological, climatic or social effects. Even small interventions can have a big impact, especially in densely built-up neighborhoods with little green space.

But how much space is enough? Research shows that even small reductions in sealing can bring significant local improvements. For example, it is often enough to remove just 10 to 15 percent of the area of a neighborhood from sealed surfaces to significantly reduce the risk of flooding after heavy rainfall. For noticeable temperature reductions, somewhat larger scopes are necessary, especially if fresh air axes or cold air generation areas are affected. This is where scenario technology comes into play: digital models simulate how different degrees of unsealing affect the microclimate, biodiversity or the water balance. In this way, targets and priorities can be defined based on evidence.

In addition to ecological criteria, economic and social aspects play a central role. Which areas can be unsealed at a reasonable cost? Where is there acceptance among owners, residents or users? Where will new conflicts of use arise, for example between parking space, delivery traffic and urban greenery? The earlier these questions are addressed in the planning process, the greater the likelihood of success. The key lies in overarching cooperation: urban planners, landscape architects, water management experts, sociologists and economic experts must all pull together – supported by intelligent data platforms and participatory tools.

Finally, impact monitoring must not be forgotten. What use is the best unsealing measure if its effects cannot be measured or traced? Monitoring approaches – from soil sensors and satellite images to citizen feedback – provide valuable data on effectiveness. They help to prove the return on investment for the urban climate, biodiversity and quality of life – and to anchor unsealing as a permanent component of urban transformation strategies.

Methodological diversity: innovative instruments and best practice examples

The practice of unsealing is remarkably diverse today – and often surprisingly creative. In addition to the classic methods of removing road surfaces, parking lots and industrial areas, more and more innovative approaches are coming into play. Modularity, temporary uses, participatory processes and the integration of digital tools are opening up new scope for the transformation of urban spaces.

One outstanding example is the city of Zurich, which is systematically unsealing and redesigning public spaces with its “Stadtgrün 2025” program. Not only are traffic islands and parking lots being removed, but schoolyards, courtyards and commercial areas are also being rethought. The close integration with the city’s climate and biodiversity strategy is crucial – as is the consistent use of GIS-based analyses to prioritize and monitor success. Similar approaches can be found in Vienna (“GrünStadtKlagenfurt”), Hamburg (“Blue-Green-Streets”), Munich (“Grüne Inseln”) and increasingly also in medium-sized and small municipalities.

One trend is the transformation of previously purely technical infrastructure into multifunctional spaces. Abandoned railroad embankments are becoming linear parks, abandoned industrial sites are being transformed into urban gardens, and parking lots are mutating into temporary cultural venues or rainwater reservoirs. Such measures are particularly effective when they are flexible and modular: mobile planting islands, greened rainwater troughs, temporary play and recreation areas. This not only creates ecological added value, but also social amenity value and new spaces for encounters.

Digital tools are increasingly playing a key role. With the help of “urban digital twins” – digital twins of the city – scenarios can be played out, effects simulated and participation processes visualized. This allows citizens, administrators and politicians to decide together where and how unsealing makes the most sense. Monitoring and maintenance are also supported digitally: Sensors record soil moisture, temperatures or biodiversity, while apps enable feedback and participation in real time.

Participatory approaches are also becoming increasingly important. Unsealing is particularly successful when it is seen as a community task. Citizen participation, neighborhood workshops and cooperative planning ensure acceptance, identification and sustainable maintenance of the new areas. This not only creates green oases, but also social innovations and new forms of urban neighborhoods.

The variety of methods shows that there is no one best way of unsealing. Successful projects combine classic engineering skills with innovative materials, digital planning and social creativity. Those who remain open to new ideas and bring different disciplines together transform deconstruction into progress – and take urban development to the next level.

Legal, economic and cultural stumbling blocks – and how to avoid them elegantly

As beautiful as the vision of strategic unsealing sounds, the reality is often more complicated. Legal and administrative hurdles, economic interests and cultural reservations slow down progress in many places. Those who do not act strategically here quickly get stuck in a maze of responsibilities, regulations and resistance.

A central problem is the question of ownership. Many potential unsealed areas are in private hands – from housing associations to companies and individuals. Without incentives, subsidies or regulatory pressure, the willingness to dismantle remains low. Creative models are needed here: from cooperation agreements and tax benefits to urban development contracts that enable unsealing in return for redensification or building rights.

Building law is not always a friend of unsealing either. Development plans, parking space regulations or monument protection requirements often make flexible conversions difficult. If you want innovative solutions, you have to make use of legal leeway – for example through experimental clauses, special uses or temporary permits. The combination of unsealing with interim uses, cultural projects or urban agriculture in particular offers new opportunities here.

From an economic perspective, the question of costs and benefits arises. Unsealing is not a cheap pleasure – deconstruction, soil remediation and redesign cost money. Funding programs, climate funds and municipal budgets help to bear the financial burden. It is equally important to communicate the long-term benefits: less heat, less flooding, better quality of life and higher property values. Proving these added values wins partners in business, politics and civil society.

Finally, culturally, unsealing is often a question of habit. Asphalted squares are seen as “clean”, green spaces as “high-maintenance” or “unsafe”. Only education, participation and visible success can help here. Pilot projects, district festivals, temporary installations and creative interim uses show how attractive unsealed spaces can be – and break down reservations. Change takes time, courage and convincing images.

Those who recognize stumbling blocks early on and deal with them elegantly make unsealing a model for success. An integrated strategy that takes legal, economic and cultural aspects into account from the outset – and reacts flexibly to new challenges – is crucial. This turns a supposed problem into a real locational advantage for the city of tomorrow.

Outlook: Digitalization, monitoring and the future of urban unsealing

The unsealing of the future is digital, data-based and networked. Modern technologies open up new opportunities to make decommissioning not only more efficient, but also smarter and more participatory. Digital twins, GIS-supported area analyses, sensor technology and big data are turning classic demolition into a highly precise control instrument for urban development.

Urban digital twins – digital images of the city – make it possible to simulate unsealing as part of complex urban processes. How does the microclimate change when a street is demolished? How does a new green space affect the water balance, biodiversity or social interaction? By linking with real-time data and scenario technology, such questions are no longer answered retrospectively, but in advance. This makes planning more flexible, transparent and comprehensible.

Monitoring is becoming increasingly important in this context. Sensors continuously record soil moisture, temperature, air quality and biodiversity. Apps and online platforms allow citizens to contribute their experiences, wishes or problems. This creates an ongoing feedback system that makes successes visible, highlights deficits and enables adjustments to be made. Unsealing becomes a learning process that adapts dynamically to new challenges.

Digitalization also opens up new potential for participation. Virtual city walks, digital participation platforms and interactive maps make planning accessible and comprehensible. This allows different groups – from residents and businesses to politicians – to decide together where and how to unseal. This increases acceptance, identification and the sustainability of the measures.

Looking ahead, unsealing will become an integral part of urban transformation strategies. It is no longer an isolated measure, but an integral part of climate resilience, biodiversity promotion, mobility transition and social urban development. Those who take advantage of the opportunities offered by digitalization will anchor unsealing as a dynamic, learning and participatory element in the DNA of the city of tomorrow – and set standards for truly sustainable urbanity.

Conclusion: unsealing is far more than the technical restoration of urban surfaces. It is a strategic, interdisciplinary and increasingly digital task that has the potential to make cities more resilient, liveable and sustainable. Targeted and evidence-based unsealing creates measurable added value for the climate, biodiversity and urban society. The strategic approach is crucial: data-based prioritization, innovative methods, integrated planning and participatory processes. Legal, economic and cultural hurdles are real, but can be overcome – with creativity, cooperation and perseverance. The future of unsealing is networked, digital and open to change. It belongs in every plan, in every urban development concept and on the agenda of the urban avant-garde. Those who invest today will reap green dividends tomorrow – and write a new chapter in sustainable urban design.

21.12.2024

Trade

Where will people of the future eat?

Building design

Part of the jury (from right to left): Frank Waldecker

Eating is and will remain a basic human need. What may change in the future, however, is where and how we eat. The student competition “Restaurant of the Future – Gastronomy 4.0” addresses this exciting topic. The jury meeting took place on January 17, 2018.

Eating is and will remain a basic human need. What may change in the future, however, is where and how we eat. Baumeister and the trade magazine Gastronomie-Report took on this exciting topic by jointly organizing the student competition “Restaurant of the Future – Gastronomy 4.0”. The jury meeting took place last Wednesday.

Every two years since 2004, Gastronomie-Report has organized the world’s only ideas competition for the gastronomy of the future – in 2018 for the first time with the architecture magazine Baumeister, which is why there is now a stronger focus on architecture. The participating students addressed the question of what the restaurant could look like in 20, 40 or 60 years – determined by digital and global developments – and what opportunities architecture offers to create gastronomic experiences.

In a jury meeting on January 17, 2018 at the Callwey publishing house, the 30 or so entries were discussed and evaluated. In addition to Willy Faber from Gastronomie-Report and Sabine Schneider and Anja Koller from Baumeister, the jury included other experts from the fields of architecture and gastronomy: These were Munich restaurateur Frank Waldecker, industrial designer and architect Philipp Zimmermann, Sascha Arnold from Arnold/Werner Architekten and Ann Sophie Brune-Bau, industrial designer and architect.

The designs

The architecture students’ designs inspired the jury members to engage in intensive and controversial discussions. It became clear that it is difficult to predict the directions in which society will develop – however, the designs give a foretaste of the exciting ideas that budding architects have in terms of restaurant design and the trends that are emerging. The general tenor was on topics such as scarcity of resources, sustainability and recycling as well as the transparency of production processes and experiential gastronomy.

Students from the following universities took part in the competition: Burg Giebichenstein University of Art and Design Halle, Berlin University of the Arts, University of Stuttgart, RWTH Aachen, FH Dortmund, Münster School of Architecture, FH Aachen, RheinMain University of Applied Sciences, TU Braunschweig, University of Hanover, TU Berlin, TU Munich, TU Dortmund, TU Cologne, TU Kaiserslautern, TU Delft (Netherlands), Staatliche Akademie der Bildenden Künste Stuttgart.

And so it goes on!

The first three places will be announced at Intergastra 2018, which will be held in Stuttgart from February 3 to 7. The first prize winner will receive 1,500 euros, the second 1,000 euros and the third 500 euros. In addition, everyone who submitted a work to the competition will receive a one-year subscription to Baumeister.

24.01.2025

Rigole: Innovative drainage concepts

Building design

Infiltration trenches serve as underground storage structures that absorb rainwater and slowly release it again. Credit: Wikicommons

Increasing urbanization and climate change pose enormous drainage challenges for cities around the world. Heavy rainfall events and rising floods are endangering infrastructure and the quality of life of residents. One innovative solution for overcoming these challenges is infiltration trenches, which are becoming increasingly established as sustainable drainage solutions. They offer an environmentally friendly way of storing excess rainwater and draining it away in a controlled manner.

Infiltration trenches are underground storage structures that absorb, store and slowly release excess rainwater. They consist of a layer of permeable material that allows water to seep into the ground instead of being discharged into the sewer system. In many cases, infiltration trenches are designed as part of an infiltration drainage system that also incorporates natural resources such as soil and plants into the water balance.

Essentially, infiltration trenches are infiltration-capable rainwater storage tanks that serve as an efficient solution for drainage and flood prevention in urban areas. They typically consist of the following components:

Inlet systems: These direct the rainwater into the infiltration trench. This can be done via gutters, manhole covers or channels.
Storage area: This part of the infiltration trench consists of a permeable material such as crushed stone or gravel, which stores the water and prepares it for infiltration.
Filter or geotextile layer: This layer prevents the ingress of dirt or sediment that could clog the system.
Outlet system: A controlled outlet allows the slow and controlled release of water into the ground or into the sewage system to prevent overloading.

Infiltration trenches work according to a simple but effective principle: they collect excess rainwater and channel it into the ground, where it can either seep away or gradually drain into the groundwater. The principle is based on the soil’s natural ability to filter and store water.

Water absorption: Rainwater is directed into the infiltration trench via the inlet systems.
Storage: The water is collected in the permeable storage layers of the infiltration trench, which temporarily store it while it awaits infiltration.
Infiltration: The water slowly infiltrates into the ground, reducing pressure on the sewer system and the risk of flooding.
Slow release: If the storage capacity of the infiltration trench is exceeded, the outlet ensures that the excess water drains away in a controlled manner.

The speed of infiltration depends on the soil conditions and the capacity of the infiltration trench. This slow and targeted release regulates the amount of water runoff and at the same time minimizes the risk of erosion and flooding.

The use of infiltration trenches for the drainage of urban areas offers numerous advantages:

Prevention of flooding: Infiltration trenches reduce the load on the urban drainage system as they absorb some of the rainwater and delay runoff. This reduces the risk of flooding after heavy rainfall events.
Promotion of groundwater recharge: Infiltration of rainwater recharges the groundwater, which is particularly important in areas where water is scarce.
Reducing the load on the sewage system: Infiltration systems reduce the need to expand expensive and energy-intensive sewage systems, as they efficiently control water runoff and reduce the load on the sewers.
Promotion of biodiversity: The storage of rainwater can lead to the greening of urban areas and the promotion of green spaces, which improves the urban climate and increases the quality of life.
Cost efficiency: Compared to conventional drainage systems, infiltration systems are more cost-effective as they require little maintenance and can be easily integrated into urban infrastructures.

The integration of infiltration systems in urban areas requires careful planning and consideration of the local conditions. In cities where the soil is not very permeable or where space is limited, alternative solutions such as infiltration trenches with water-permeable concrete slabs or special materials that enable good water absorption must be considered.

Another important aspect is the cooperation between urban planners, engineers and the population. Often, infiltration trenches need to be used in combination with other sustainable drainage solutions such as green roofs, rain barrels or infiltration swales to create a comprehensive solution for rainwater harvesting.

Cologne, Germany: In Cologne, infiltration trenches have been installed in various parts of the city to relieve the sewer system and prevent flooding during heavy rainfall. A particularly successful example is the “Green Belt” in Cologne, where infiltration trenches are part of a comprehensive drainage concept that also takes green spaces and sustainable urban development into account.
New York City, USA: In New York, infiltration trenches have been integrated into several neighborhoods as part of the “Green Infrastructure” project. This has led to a significant reduction in surface runoff and helped to relieve pressure on the sewer system during peak periods.
London, Great Britain: In London, the Sustainable Drainage Systems (SuDS) scheme was launched, with infiltration systems installed in several new development areas and public spaces. This helps to manage water runoff and mitigate the effects of heavy rainfall.
Singapore: Singapore has introduced infiltration trenches as part of its comprehensive strategy to improve urban water management. Here, infiltration trenches are often combined with other solutions such as rainwater storage and green roofs to protect the city against flooding.

Infiltration trenches are a promising solution for the sustainable drainage of cities, which are increasingly struggling with flooding due to heavy rainfall and urbanization. Not only do they offer ecological benefits by promoting water absorption and storage in the soil, but they also help to reduce the burden on sewers and infrastructure. The integration of infiltration trenches into urban drainage systems is an important step towards sustainable and climate-resilient urban development.

More on the topic and our STOP THE FLOOD campaign here.