Setting a good example for sustainable architecture: all-natural materials for Berlin school extension

Contemporary architecture and sustainability are becoming inseparable. The energy efficiency of buildings, the sustainable use of construction materials and the ways in which buildings can contribute to reducing the impact of climate change are inspiring and motivating architects across the world. The extension of the Free Waldorf School in Berlin is one of those cases that makes us dream of a well designed, eco-friendly tomorrow.


Berlin, Germany

Project completion


Designed by

MONO Architekten

Project type

New build

Building type


Roof surface

450 m2

Roofing membrane

Elevate RubberGard EPDM 1,5 mm

In 2015, German architectural practice MONO Architekten was assigned a very ambitious redevelopment project at the Free Waldorf School in Prenzlauer Berg, Berlin. Their task was to extend the original prefabricated building from the 1970s by creating a brand new after-school building.

For this new structure, architects at MONO chose to completely depart from the school's original architectural style and use more contemporary, organic shapes instead. Their design for the new after-school centre consists of a cluster of curved pentagonal volumes of different sizes and heights, with the roof slopes going in different directions. Topped with green roofs, the overall effect is reminiscent of lush mossy stones.

Sustainability was at the core of the project, and MONO Architekten used natural and renewable materials wherever possible. The structures of the extension are timber framed and walls are built from straw and clay plaster. Untreated larch wood planks of various widths serve as exterior cladding, which truly evokes the feeling of a calm oasis in the middle of the busy European capital. The extensive green roof system perfectly completes this approach by providing more space for nature. And it’s not just about looks.

In addition to their aesthetic value, green roofs offer many benefits, particularly in urban settings. To start with, they have an overall positive effect on people’s health and well-being, providing a good environment for social interaction, something especially important in a public space such as a school. For the extension of the Free Waldorf School, a mix of low-growing herb grasses was the vegetation of choice. During the flowering season, it will offer a colourful picture to the children and attract beneficial insects such as pollinators, improving  local biodiversity.

Green roofs also help mitigate the “urban heat island effect” by returning moisture to the environment. Moreover, they provide thermal and sound insulation. Both advantages are very important in school settings. 

To accommodate the creative vision of the architects, the roofing membrane for the new after-school extension had to be sustainable, efficient, versatile and flexible, offering a perfect fit for the irregular shapes of the building. It also had to be lightweight and robust enough to provide a durable basis for the green roof system.


With this long list of requirements, MONO Architekten specified an EPDM roofing membrane for the project. 

The sustainable features of EPDM are widely recognized by institutions and environmental organizations. Greenpeace, GreenTeam and the Dutch Institute for Building Biology and Ecology (NIBE) have named it as the roofing membrane with the least environmental impact that offers a durable, long-term solution for modern architecture. In its latest evaluation, NIBE states that EPDM roofing membranes are the most environmentally friendly choice for flat roofs. What are the specific criteria of this evaluation? Carried out every two years, it compares the initial costs (material and installation costs) as well as all hidden environmental costs (raw material consumption, energy consumption during production) of roofing membranes from different manufacturers. 

How exactly did EPDM make a good fit for the Free Waldorf School project in terms of design freedom? First of all, it’s single-ply, which means it can adapt to irregular shapes very easily, following the geometry of the support and accepting its various expansions and retractions without ever saturating or breaking. Unlike many other roofing membranes, it also returns to its original structure after stretching. 

Finalized in June 2017, the project was one of the winners of Germany’s Federal Timber Construction Plus 2018 competition, in the category "Public Building - New Buildings & Existing Buildings". The German Federal Ministry of Food and Agriculture grants this prize every two years, rewarding exemplary buildings made with renewable raw materials.

This project was  also nominated for the Deutsches Architekturmuseum (DAM) Award for Architecture 2020, one of the most renowned architecture awards in Germany.


Extensive green roof system


Elevate RubberGard EPDM roofing membrane


PIR insulation (MF)


Vapor control membrane (bitumen)


Wooden roof deck

There is a lot to
discover about EPDM

EPDM is the most future-proof roofing solution when it comes to sustainabilityperformance and design freedom. Learn more about the role it played within this project and many others by discovering its benefits.

How did EPDM elevate this project?

Green Roofs

Green roofs cool down and insulate. Reduce noise. Create habitats for birds and insects. All great features. However, it’s only made to last when it’s designed carefully and installed on the non-toxic root-and water resistant EPDM membrane.


Freedom of design is key to those creating big things. Thanks to its flexibility and availability in big, single-ply sheets, EPDM supports creative solutions. It also enables future transformations and placing new objects on the roof.

The future of roofs is green

Roofs represent about 20–25% of the total urban surface area. What is particularly visible on satellite photos is that we are not making the most of our roofs yet: more often than not, they stay empty. At the same time, as cities continue to grow and expand, becoming warmer and noisier in the process, roofs are expected to go beyond their primary function of ensuring watertightness. More than just “covers” on top of buildings, they need to contribute to their energetic efficiency, sustainability and overall reduction of the environmental impact. Green roofs are among the best solutions that address all these needs.