From rubble to a new urban green space: integrating climate resilience into the reconstruction works of a cultural and creative centre in Bratislava, Slovakia

Bratislava is the capital and biggest city in Slovakia. A high proportion of built-up areas and paved surfaces characterizes the city and there is a lack of attractive recreational areas for the urban population (SECAP, 2024).

The increase of the urban population has already resulted in a significant decline of green areas (Holec et al., 2020). By 2050, the population of Bratislava is expected to further increase by 6.43% (Bratislava 2030), which contributes to drive the ongoing spread of built-up areas. Extensive residential development is also planned in the area around Nová Cvernovka. The decline of green areas in cities changes the microclimatic conditions and contributes to the urban heat island effect, i.e., higher air and surface temperatures in urban areas in contrast to the surrounding rural landscape (Holec et al., 2020). This results in increased vulnerability to climate change impacts such as heat waves, droughts and torrential rain, which have been occurring with increased frequency and severity in the last three decades (Lückerath et al., 2019; case study on EEA grants for Bratislava).  Projections for the whole country suggest increasing temperatures and a significant change in the annual pattern and timing of precipitation. This includes a slight to moderate increase in total precipitation in the cold season. The projections also show an increasing precipitation variability during the warmer part of the year, with longer seasonal dry periods and short rainy periods with heavier precipitation (Adaptation Strategy of the Slovak Republic to Climate Change).

Bratislava experienced a major industrial boom at the turn of the 19^th and 20^th century. During the post-socialist transformation, many former industrial sites were demolished, and only some historic buildings have been preserved (Kristiánová et al., 2016).

The former Secondary Industrial School of Chemistry, located in the Nové Mesto district in Bratislava, was originally built as an administrative building for the neighbouring chemical plants. When the building was abandoned in 2010, it started to fall into disrepair. When the Cvernovka Foundation reconstructed it into a cultural and creative centre, around 300,000 m³ of construction waste remained on the former school yard. As the permanent deposition of construction waste on the property is legally not allowed, it was supposed to be transported to a landfill. However, this would have caused considerable costs (around EUR 50,000), resulting in high transport-related CO₂ emissions, and would thus be neither economically, nor environmentally sustainable.   In Slovakia, the proportion of waste that is deposited in landfills is significantly higher than in the rest of the EU (more than 50 %) (Greener Slovakia – Environmental Policy Strategy). Additionally, large amounts of mixed municipal waste and construction waste are deposited in illegal landfills, leading to the potential contamination of soil, water, and air (IEP, 2016).

The main national strategy documents for adaptation to climate change are the Adaptation Strategy of the Slovak Republic to Climate Change, adopted in 2014 and updated in 2018, and the National Action Plan (2021). At the local level, the Bratislava Sustainable Energy and Climate Action Plan 2030 (SECAP, 2024) outlines measures to reduce emissions and enhance the resilience to climate change impacts. To adapt to climate change, the plan suggests developing green and blue infrastructure, fostering rainwater retention, enhancing biodiversity, increasing the protection of public health during heatwaves and improving crisis management. Moreover, the use of materials that prevent excessive absorption of solar energy was valued as to contribute to minimising the urban heat island effect. The revitalisation of parks and public spaces is a central element of the SECAP, which is fostered by the Living Places program.

The recovery of construction waste is in line with the Strategy for Municipal Waste Management in Bratislava 2021 - 2026: Transitioning to a Circular Economy, which was adopted in 2021. It aims to increase the rate of waste sorting and recycling, while reducing the rate of landfilling. The transition to a circular economy is also promoted in the Greener Slovakia – Environmental Policy Strategy (2019), but it does not explicitly include a strategy for the restoration and reuse of material from construction waste.

The main aim of the Nová Cvernovka park project was to manage construction waste in a sustainable way by recycling and reusing it for building a public park that prevents overheating during summer and retains water in the soil. This solution contributes to a number of environmental and social objectives in line with the local and national policies outlined above:

• Creating recreational space for the urban population: The project aims to address the lack of attractive recreational areas for the urban population in the Nové Mesto district by offering a park with diverse amenities (art installations, terrace with gastronomic offer, sauna, playground, cultural events).
• Increasing biodiversity: By expanding the green area, tnew habitat for birds and pollinating insects is provided.
• Reducing costs: Recycling and reusing construction waste on-site as building material contributes to reducing costs that would otherwise have incurred for the transport and disposal of the construction waste, and for the procurement of conventional building material.
• Efficient use of raw material: No additional building raw material needs to be extracted, produced, and transported to the construction site, which saves greenhouse gas emissions and reduces other environmental impacts.
• Awareness raising: Visitors of the Nová Cvernovka centre and park are inspired to think about environment-friendly alternatives to conventional waste management. This is supported by various educational and awareness-raising activities, specifically targeting younger generations.
• Strengthening the community: The Nová Cvernovka park is a community-driven project. The sorting and recycling of the construction waste was largely carried out by volunteers, and financial support was provided through a fundraising campaign.

Shaping the Nová Cvernovka park from recycled rubble

The rubble generated from the reconstruction works of the cultural and creative centre Nová Cvernovka was recycled and repurposed to create the built features of the surrounding public park (Suť na park).

The proposal emerged in response to the high costs and adverse environmental impacts associated with disposing construction waste in landfills. The community started by organising a festival that combined creativity, art, design, innovation and environmental thinking, with the aim to raise awareness about current environmental problems and possible solutions. Since reusing construction waste as building material is not a conventional solution, a self-made recycling mechanism for sorting construction waste powered by human energy (“Rubblebicycle”) was developed. Additionally, the community researched the material and organised a workshop to test how the material could be processed. Scientific expertise on compacted water-permeable surfaces was provided by a Professor at Czech University of Life Sciences in Prague.

The aim was to create a solid surface for the park’s built-features (e.g. pathways, walkable surfaces), able to retain water without becoming muddy.  Building a surface which is water-permeable and water-retaining at the same time, different layers of material are needed. This approach is based on the German DIN standard DIN 18315 | 2023-09 for unbound surfacing layers in road construction. In parks, this type of surface is normally built using granite. In the case of Nová Cvernovka, crushed concrete, bricks and ceramics have been used.

To obtain the material for the individual layers of the threshing surface, firstly, volunteers sorted the rubble manually into individual materials and fractions. Further, certified machines were used for obtaining the final recycled material. To ensure the safe transformation of waste into building material, this was tested according to the STN EN 933-1 (European standard for determining the particle size distribution using the sieving method). Laboratory reports confirming that the recycled material did not represent any environmental risks were commissioned. The individual components (from dust to larger components measuring 32 mm) were then mixed to obtain the required composition. Finally, they were applied in layers on the dredged surface. The mixture was continuously compacted and now builds a solid surface of 30 to 100 cm thickness.

In addition, dusty particles of the rubble were used to create other solid building elements as add-ons of the park, while the wood from the ceiling of the former school building was used to build flowerpots. The green area was expanded. Various plants create natural shading and habitat for wildlife, thus increasing biodiversity.

The walkable surface of the new park enables rainwater retention and evaporation, thus avoiding overheating and contributing to a pleasant microclimate. In general, the Cvernovka Foundation initiative proved that constructing the built parts of a public park from recycled construction waste is possible, and that it is even more environmentally and economically sustainable than the conventional approach.

Moreover, the creation of a floodplain meadow was completed in 2025. Its effectiveness could not be tested yet, since no sufficiently heavy and prolonged rainfall event occurred to assess its real-world performance.

Maintaining the Nová Cvernovka park

The walkable park surfaces require regular maintenance efforts. Maintenance includes the removal of weeds and self-seeded plants to avoid the disruption of the paving material.The clearing of leaves and organic waste in autumn by lightly raking the surface ensures that the permeability of the surface is maintained. Moreover, heavy use of the surface or torrential rainfall can cause unevenness, depressions, or small water channels on the surface. The area needs to be occasionally raked and levelled locally to prevent water from pooling in puddles. Resealing and consolidating the structure is especially important in spring, as freezing and thawing can cause the surface to heave. Over time, material loss occurs due to weather conditions (wind and rain). Once every few years, the fine surface layer of the recyclate needs to be replenished and compacted again. Moreover, the compacted aggregate surface needs to maintain a slight moisture level, which naturally binds the material together and prevents dust. Thus, the area must be lightly sprinkled with water especially during long, dry summer heatwaves.

The Nová Cvernovka park is a community-driven project that would not have been successful without the support of volunteers.

The initiative to transform construction waste into a public park was started by members of the Nová Cvernovka foundation, a community of people working in culture, art, creative industries and non-governmental organisations. In 2018, the “Nasuti” festival was organised, which combined contemporary art with innovation and ecological thinking to raise awareness of current environmental problems and solutions. The international exhibition “Human by Design” under the auspices of the Slovak Design Centre followed in 2019. It presented a recycling mechanism for sorting construction waste powered by human energy (“rubble bicycle”). The architectural studios Labak and 2021 created an architectural and landscape study for the revitalization of the park. Residents of the neighbouring area were involved in this process, to ensure the park is designed according to their needs.    

The project was also supported by expert knowledge. For example, scientific expertise on threshing surfaces was provided by the involvement of the Czech University of Life Sciences in Prague. An expert for sustainable transport from the civic association Cyklokoalícia supported the planning of a cycling path.

The development of the Nová Cvernovka park mainly relied on volunteer work of the creative community, who balanced their professional work with shifts of sorting construction debris by hand. Besides manual labour, a fundraising campaign was organised, which allowed the community around Nová Cvernovka to support the realisation of the project financially.  The VÚB Foundation supported the crowdfunding campaign as the main financial donor. The Spanish and Dutch embassies, with the support from the Bratislava Self-Governing Region, donated trees through the “10,000 Trees initiative”.

The main success factor of the initiative was the dedication of people from the Cvernovka foundation to pursue the idea of building a park from construction waste despite some obstacles:

• Current legislation does not facilitate such innovative approaches, as the storage of construction waste on the premises is legally not allowed. A three-year probation, granted by the district environment office, was thus decisive, as it enabled the foundation to explore possibilities to recycle and reuse the construction waste.
• On-site recycling is not the standard approach to deal with construction waste. Therefore, the lack of capacity and experience represented a barrier. Extensive research, material testing, and expert consultations were thus necessary to develop a solution for the reuse of the construction waste. The process included a workshop to test how the material could be processed, and the development of a self-made recycling mechanism for sorting construction waste powered by human energy (“rubblebicycle”).

Community involvement and awareness-raising activities were key to the success of the Suť na park initiative. The above-mentioned festival, organised to raise awareness of current environmental problems and solutions, subsequently inspired a wider community to get involved as volunteers or support the fundraising campaign (see Stakeholder participation). However, this also caused some uncertainty and downtime, as the resources were not available from the beginning.

Replication

The Nová Cvernovka park demonstrates that construction waste can be recycled successfully and re-used to create a water-permeable and water-retaining surface of built park structures. It serves as a blueprint for how urban brownfields can be revitalized through local initiative and public-private partnerships. In cooperation with 3E – Institute of Environmental Education, the approach was applied to another yard in the Nové Mesto district in Bratislava, proving the replicability in various urban environments (see https://www.sutnapark.sk/).

Costs

The selected solution was more cost-effective compared to conventional alternatives. The project avoided the costs associated to the transport and disposal of the construction waste into landfill which were estimated around EUR 50,000. Since the material was directly recycled onsite, additional financial resources for using new building materials were saved.

As the development of the Nová Cvernovka park is an ongoing process with continuous development, the total investment costs are uncertain and not available.  Around a third of the funding was provided by the Cvernovka Foundation. Moreover, around EUR 20,000 (e.g., for renting equipment and machines) were collected in an online fund-raising campaign. The work was carried out mainly by volunteers, which contributed to reduce the costs.

Additional costs are related to the ordinary maintenance of the park, as described in the Solutions section.

Benefits

The main benefit of the park is the contribution to climate change resilience. The water-permeable and water-retaining surface of the park enables rainwater retention and evaporation, thus creating a pleasant microclimate and reducing the urban heat island effect. The green area provides additional cooling and natural shading.

In terms of environmental benefits, reusing resources contributed to save approximately 20 tons of CO₂ emissions by avoiding waste disposal as well as the extraction, production and transport of conventional raw materials. The expansion and renovation of the park increases local biodiversity and creates habitat for pollinator insects and birds. The use of water retaining surfaces can also reduce the need for irrigation of the surrounding vegetation.

Beyond the environmental benefits and cost saving, the park also addresses social issues. It provides recreational space in a district characterized by a lack of attractive green areas, and serves as a venue for cultural events, community gatherings and educational activities. The participatory nature of the project has furthermore strengthened social cohesion within the Nová Cvernovka community and beyond.

The park is now especially popular among young people, cyclists and families, and regular social and cultural events such as concerts, discussions, and neighbourhood barbecues contribute to strengthen the community.

The Nová Cvernovka park is a long-term project, which progresses gradually. The initial idea emerged in 2016, after the reconstruction of the Nová Cvernovka cultural and creative centre, which was finalised within nine months. A three-year probation allowed the Cvernovka foundation to explore valid options to recycle and reuse the construction waste as building material for a public park. The time was also needed to secure sufficient human and financial resources, i.e., motivating people to contribute to a fundraising campaign or volunteer for the sorting and restoration of construction waste. After that, the on-site sorting and recycling of construction waste into building material was conducted within just a few months and the park was opened in July 2020.     

The Nová Cvernovka park is planned to serve as an attractive recreational area and a green space for climate resilience valuable for the urban population in the long term, also considering the planned future residential development in the area around the cultural center. 

However, the longevity of the park requires regular maintenance efforts (e.g., watering of plants, reprofiling, replenishing and compacting the surface, removing organic waste to maintain the permeability of the surface (see Solutions). This requires continuous commitment by the community.

Cvernovka Foundation 

info@novacvernovka.eu

Bratislava 2030: Starostlivé, dostupné a odolné mesto, v ktorom chceme žiť (2022): Bratislava-2030_publikacia_032023_compress.pdf (in Slovak only)

Bratislava Sustainable Energy and Climate Action Plan 2030 (SECAP) (2024): https://bratislavask.s3.bratislava.sk/upload/SECAP_Sustainable_Energy_and_Climate_Action_Plan_EN_6f81e109ad.pdf

Holec, J., Feranec, J., Šťastný, P., Szatmári, D., Kopecká, M., & Garaj, M. (2020). Evolution and assessment of urban heat island between the years 1998 and 2016: case study of the cities Bratislava and Trnava in western Slovakia. Theoretical and Applied Climatology, 141(3–4), 979–997. https://doi.org/10.1007/s00704-020-03197-1

Kristiánová, K., Gécová, K., & Putrová, E. (2016). Old industrial Sites – Conversion to parks: Potential of Bratislava. Procedia Engineering, 161, 1858–1862. https://doi.org/10.1016/j.proeng.2016.08.709