Green roof over the school - a symbolic and tangible response to climate change

During the renovation of the Szent Antal Ferences Grammar School in Esztergom, better known as „Franka”, the 2,200 square metre intensive green roof built on top of the new sports hall is an outstanding achievement not only in terms of aesthetics but also in terms of construction quality, emphasises the statement sent to our newspaper by Mapei Kft. in a statement sent to our newspaper. This is recognised by the 2025 Roof of the Year Award, which was presented to Balogh Szig-Bád Kft., the company responsible for the waterproofing work.

This green space is not only important from a sustainability point of view, but also serves a community function for the people who visit the institution. The landscaped area also features a walkway, flower boxes, grassed areas, thermo ash seating and a three-stage outdoor stage

- emphasise.

"Green roofs are a clear response to climate change, especially in the fight against the urban heat island effect. But the long-term viability of such a system depends primarily on waterproofing - the Achilles heel of green roofs. It is therefore of paramount importance to use reliable, root-resistant and durable materials for the construction. We are proud that Mapei's solutions have created this masterpiece," said Bela Markovich, Managing Director of Mapei Kft..

The natural properties of colours and materials have been turned against the heat

The benefits of green roofs contrast best with a traditional flat roof covered with tarmac. Flat roofs insulated with black tar act as a heat trap in hot weather: the dark surface absorbs the sun's rays, which are converted into heat, so the roof can reach temperatures of up to 70-80°C. The heat is transferred downwards into the building, especially if the insulation is inadequate, and the resulting heat stays inside. As tar and concrete cool slowly, the temperature does not drop significantly at night, making the interior stuffy, increasing the energy demand for cooling and contributing to the urban heat island effect," explains Béla Markovich.

In contrast, the green roof is a veritable oasis. Roof vegetation and growing media provide shade, insulation and heat storage, reducing overheating in summer and heat loss in winter. This means not only more comfortable interiors, but also lower energy consumption and energy bills. According to a comprehensive US government report, a green roof installed on a public building pays for itself in an average of 6.2 years, while generating an average annual return of 5.2 percent for its owner. And over its lifetime, it returns more than twice the value of the investment.

Green roofs also add a lot of functionality to the urban environment. They significantly reduce stormwater runoff, relieving the strain on overloaded sewer systems - a well-designed green roof can reduce the amount of water coming off the roof by up to 65 percent. They also cool the air naturally: evaporation from vegetation can significantly reduce the urban heat island effect. It is also ecologically beneficial, providing habitat for pollinators and birds, while protecting the roof structure from UV radiation and weather extremes - potentially doubling its lifetime.

Flooding on the roof: how waterproofing was tested

Waterproofing has always been one of the biggest challenges for green roofs: constant moisture, root pressure, mechanical stress and weather all combine to make them extremely demanding. In the case of this project, this was achieved with a special waterproofing layering system, including root-resistant bitumen slabs, with the help of the experts at Mapei.

"Green roof leaks are difficult and expensive to repair - you need to be sure. So, as a final dress rehearsal for waterproofing, a flood leak test was carried out to deliberately flood the freshly finished roof surface. By carrying out such a test, you can be sure that the surface will withstand the weather and use over the long term."</big