A common problem in the urban landscape is that of hard, impervious surfaces such as pavements, concrete buildings or asphalt roads, preventing the infiltration of rainwater into the soil. This has the effect of increasing flood risk while limiting the recharge of groundwater reserves. Hard grey surfaces also retain large quantities of heat energy and contribute to the urban heat-island effect.

Plants, trees and green spaces on the other hand can intercept water allowing it to infiltrate into the soil. Through evapotranspiration and the provision of shading, vegetation can help to cool the urban environment.

To reduce the area of impervious surfaces, the City of Antwerp organised the initiative of “Break Out” (Flemish: BreekUIT) which made citizens aware of the issue through a series of webinars and encouraged them to depave their property. For each 0.1 m² of hard surface that citizens removed on their own courtyard, terrace, front or rear facade, they received a free plant in return.