GREEN ROOF AND WALLS FOR BUILDINGS Guidelines for Public Administration and Territorial Bodies

By project NACAO

Published on 31 March 2025

Italy

About this good practice

The implementation of plant systems such as Green Roofs and Vertical Greenery Systems represents an innovative solution to improve the urban environment, reduce CO2 emissions and positively influence the microclimate. These systems improve the thermal comfort of buildings, filter dust and mitigate the effects of heat islands thanks to plant evapotranspiration and shading. In order to support the Public Administration and local authorities in the implementation of these infrastructures, ENEA (National Agency for New Technologies, Energy and Sustainable Economic Development) – Department of Energy Efficiency Unit, has developed specific Guidelines dedicated to Green Roofs and Walls. This tool provides a comprehensive knowledge framework and provides a legislative overview at European and national level, as well as a summary of national calls to finance green infrastructure. The presence of plant systems in the vicinity of a building also affects the energy interactions between the building and the external environment, improving summer comfort for outdoor spaces and performing the function of thermal insulation, with consequent limitation of thermal oscillations. In addition, green roofs and walls are able to mitigate summer temperature peaks thanks to plant evapotranspiration and shading against direct solar radiation on buildings and surrounding surfaces, allowing to mitigate the physical effects of heat islands in city centres.

Expert opinion

European cities experience more frequent and severe effects of climate change. Urban areas experience these impacts more acutely due to their design, dense infrastructure, sealed surfaces and high population density. Green roofs and green walls are elements of green infrastructure, which can help to mitigate these impacts. Green roofs help to regulate temperature inside the building, catch up to 60% of stormwater, thus reducing water runoff and mitigate the urban heat island effect. Moreover, they are important for increasing biodiversity and can be used for urban food production. Green walls include most of the benefits of green roofs. Additionally, they can reduce surface temperature of the building behind them by as much as ten degrees Celsius, reduce sound reflections and lower energy costs of cooling in summer months by over 20%. The guidelines developed in this good practice are an excellent way to make green roofs and walls more spread in Italy, by providing practical and regulatory support with their implementation. Other regions in Europe would benefit by transferring this good practice and implementing it in their area.

Magda Michaliková

Works at Interreg Europe Policy Learning Platform

Resources needed

The Guidelines were drafted as part of Italia in Classe A campaign, promoted by the Ministry of Environment involving internal expertise as regular staff work. Local authorities voluntarily contributed by an online questionnaire. No extra budget was used outside of the Italia in Classe A program.

Evidence of success

Guidelines has generated significant interest, 436 views on 4/7/24, freely available online, inspire public administrations' policies. Green roofs and walls reduce summer cooling (25-50%) and winter heating (10-30%) costs improving the energy efficiency of buildings. They lower building surface temperatures by 20-30°C, helping to mitigate the urban heat island effect. These actions lead to quantifiable environmental outcomes, highlighting their role in promoting sustainable policies.

Potential for learning or transfer

The EU Commission also recognises that efficient, energy-efficient buildings that integrate ecological elements such as roof gardens and green walls with innovative building materials can bring environmental, social and health benefits to cities. The guidelines provide practical and regulatory support for the implementation of sustainable building solutions, helping local governments and other public bodies to understand the benefits and techniques of applying green roofs and walls, thus facilitating their deployment and integration in urban contexts. The use of these solutions as roofs of structural parts of a building represents an innovative system that allows to reduce energy consumption to cool buildings in hot periods and for heating in cold ones. The guidelines provide an overview of a topic that is increasingly considered to be a real building component.