The rooftop is 5m by 30m and is south facing with a thick north wall with rooms. The roof can easily be cover with polycarbonate and turn into a greenhouse. The system will be on top of a dormitory and has a lot of unused bunk beds. The growbeds frames are adapted from the buck beds.
The weight bearing of the tank is one of the key question and still have to find good structure engineers to help calculating the load and adjust. The filter tank is a smaller problem.
Another view into the green house. This would make nice urban escape.