The old building of the cityhall of Rotterdam is going to be renovated during 2013. Temporary it is an empty building with facades that have been shut off with wooden panels. The municipality started a design competition which is won by 2012 Architects.
In less than 3 month the design is being brought to reality and the facade is turned into a vertical garden that changes with the seasons.
The dense grid of the panels is used as a blank page on which the shape of some trees is painted. Reused flower pots are connected to the wooden panels, and a selection of 15 types of plants is spread among the facade.
Rain water is collected from the roof and stored in 8 reused tanks of 1000L each on the last floor. A timer regulates the intensity on which the water is distributed by gravity to each of the pots by a dripping system.