text: In Finland, green roofs are still scarce. Some experimental green roofs have been built in big cities. However, the capital city of Helsinki has published guidelines for enhancing the building of green roofs in the city. There is on-going research on the topic as the conditions in the southern Europe are very different from those in the north and knowledge acquired there can't be directly applied to colder climates. The fifth dimension – [https://www.researchgate.net/project/Fifth-Dimension-Green-Roofs-and-Walls-in-Urban-Areas-research-program Green roofs and walls in urban areas -research program] aims to produce high-level scientific and broadly applicable knowledge on optimal green roof and -wall solutions in Finland.