Land use is a major aspect of sustainable development, as it determines the production of ecosystem services. However, among the various uses, soil sealing is of particular concern, as it is the most dangerous land degradation process. It threatens our food security, water and air quality, climate regulation and biodiversity but it keeps on developing despite many public policies. This article considers soils as common goods and aims to examine how public action or market tools can be complemented by the mobilisation of several levels of public and private actors around a polycentric equilibrium. But, because of a frequent lack of shared vision about soil sealing, this equilibrium requires to make social norms evolve in favour of enhancing old buildings rather than using new soils. This requires creativity and a stakeholders engagement: a social innovation whose conditions this article is trying to specify.