Flanders is one of the best-known productive regions of Europe. Concentrating the majority of the Belgian industry and workforce, the Region features a continuous and dense infrastructure throughout its landscape: slabs of asphalt and concrete, tiles, sheds, wide roads, unused vegetated remnants of space, and industrial platforms. These elements cover approximately 4.5% of the urbanisation of the region and 15% of its overall land take, becoming a major question when it comes to the soil impermeabilization and water management question. This work looks at industrial platforms as umbrellas spread right across the Flemish territory. Umbrellas that every year repel approximately millions of m3 of rainwater. What if this water were retained instead? GreenWithGrey is one of the strategic projects of the “Proeftuinen Ontharding,” a programme aiming at tackling the very diffuse – and land consuming – urbanisation of Flanders through strategic desealing actions. Within this framework, GreenWithGrey explores possibilities for desealing Flemish industrial platforms to tackle questions such as providing more room for water and strengthening the regional water cycle. GreenWithGrey achieves the ongoing transition through a mix of doing and undoing, of actions and policies, of top down and bottom-up strategies.