Green Renovation: Sustainable Solutions to Climate Challenges

Our rapidly warming climate underscores the urgency of climate change mitigation every day. Extreme heat, deteriorating air quality, and peak rains increasing in number and severity profoundly impact our urban environment. The construction sector plays a pivotal role in addressing these challenges. In doing so, we observe a significant shift in strategy: renovation is increasingly preferred over new construction. By renovating existing buildings and enhancing their sustainability, the construction sector can make a substantial contribution to reducing CO2 emissions. Sustainable renovation not only improves energy efficiency but also strengthens the resilience of buildings against extreme weather conditions. Property owners and managers, government agencies, and policymakers, as well as environmental organizations and sustainability consultants, play a crucial role in championing this transition. Together, we can and must construct a sustainable future that safeguards both our cities and the environment.

Green Renovation: What Are the Opportunities and Possibilities?

Green renovation is crucial for the city’s climate adaptation. Why? Greenery cools the environment, reduces flooding, and increases infiltration capacity, which can also combat drought. By identifying the various problems caused by climate change, we illustrate the opportunities and possibilities for green renovation.

1. Extreme Rainfall -> Collect and Retain Water on the Green Roof (Where It Falls First)

We are increasingly faced with extreme weather challenges. Intense downpours, powerful storms, and prolonged periods of drought and heat are on the horizon. Moreover, the cost of protecting land from flooding is significant. Extreme weather can also lead to shortages of drinking water and food.

To mitigate flooding caused by extreme rainfall, traditional roofs can be equipped with green roofs. For rainwater management, special green roofs have been developed that can retain excess rainwater for extended periods. Thus, rainwater is collected and temporarily stored at its initial point of contact. The water is then released to the sewer system in a controlled manner, preventing flooding at street level. This type of green roof is often referred to as retention roof, Purple-Roof, or blue-green roof. The Purple-Roof, which can also be installed on existing roofs with slopes, has undergone extensive testing, proving it to be an effective green roof construction for rainwater management. Approximately half of all roofs are flat roofs, and most of these are currently not utilized. Therefore, there are significant opportunities here for collecting rainwater exactly where it falls. A major advantage of a Purple-Roof is its lightweight design, allowing it to be installed on existing buildings and thus suitable for roof renovation. This type of green roof generally complies with the local water board’s or municipality’s water regulations.

2. Heat Stress in the City -> Green Wall or Green Roof Offers Cooling Effect

With the rise of global warming, heat stress in cities is becoming an increasingly serious issue. In the past 130 years, global temperatures have risen by 1 degree. If greenhouse gas emissions continue at their current rate, the global average temperature will keep rising. This increase in temperature will not only shorten winters but also trigger the growing and flowering season earlier in the year. These changes have profound consequences for both humans and nature. Animal and plant habitats shift due to higher temperatures, which can lead to the extinction or migration of species from their original habitats. At the same time, climate change can actually expand some habitats. Notable examples include the permanent establishment of the Asian tiger mosquito and the Asian hornet outside Asia.

However, there are also risks for people in high urban temperatures. Heat can cause symptoms of fatigue, difficulty concentrating, and shortness of breath. And for individuals with cardiovascular diseases, the risk of heart attack or stroke increases. When the outside temperature becomes too high, the body struggles more to dissipate heat, risking overheating. This is particularly dangerous for the elderly or those with underlying conditions, as research by the American RIVM indicates: 250 people die annually due to heat, 31% of which can be attributed to climate change.

The study ‘The Heat-Proof City’ by the University of Applied Sciences of Amsterdam demonstrates that a 10% increase in greenery leads to a half-degree reduction in city heat. A straightforward method of greening petrified surfaces in the city is by adding a green roof or green facade to existing buildings. Greenery retains a significant amount of moisture and thus cools the surrounding area.

Therefore, the application of greenery to petrified surfaces is of paramount importance for the city. In the image below, captured with a thermal camera on a hot summer day, you can clearly see the temperature difference between a green and a non-greened/petrified surface.

In fact, not only does the presence of a green roof or green facade make the outdoor environment more pleasant, but for the indoor climate, a green roof or living wall also creates a more comfortable setting. The air conditioning system does not have to work as hard, which also leads to energy savings.

An additional advantage of greenery is its positive impact on biodiversity. Green roofs and green walls provide habitats for insects and small birds, promoting biodiversity in urban areas.

3. Poor air quality -> plants in green facade or green roof purify air

Climate change not only warms the air, the quality of the air we breathe also deteriorates significantly on hot days. This is because there is more ozone and more pollutants, pollen, and mold in the air on hot days. Reduced air quality has health implications, think of respiratory problems or allergies. Infectious diseases also get more space in warmer and more humid climates.

Plants are known for their air-purifying properties. Plants extract CO2 from the air and convert it into oxygen. Thus, they naturally create healthier air quality. The more plants, the better the air quality worldwide. Applying a green façade to a building has a great effect on the air quality in its immediate surroundings. Thanks to the high plant density of a SemperGreenwall, 1m2 of green wall removes 2.3 kg of CO2 from the air per year. In addition, this one square meter produces as much as 1.7 kg of oxygen.

So, when undertaking a facade renovation, choose to install a green facade right away. Green walls can serve as a replacement for a building’s outer shell. This is because a SemperGreenwall is completely waterproof and water-resistant.

Similarly, on the roof, Sedum plants, grasses, and herbs absorb pollutants from the air. Think of particulates and CO2. So opting for a green roof is also a good idea during a roof renovation.

Case studies: what does green renovation look like in practice?

Do you wonder what green renovation looks like in practice? Below we show a number of case studies. These are just some of the many projects we have had the pleasure of contributing to over the past decades:

Building sector collaboration – key to tackling climate change

The urgency of climate change calls for direct and concerted action from all stakeholders in the construction sector. Policymakers, businesses, and consumers each have a crucial role to play in reducing the construction sector’s impact on our climate. It is time to work together on solutions that both reduce our carbon footprint and contribute to a healthy, resilient living environment.

At Sempergreen, we are committed to sustainable construction and renovation. As an expert and trusted partner in this sector, we offer innovative green solutions that improve air quality, reduce heat stress, and promote biodiversity. Our green facades and roofs contribute to a healthier urban climate and help your project meet the highest sustainability standards.

Let’s take responsibility for a better future together. Sempergreen is ready to support you with expert advice and high-quality, sustainable products. Through ‘Replanting the Planet’, together we can build a world that flourishes both economically and ecologically.