It strikes me that the easiest way to formalise this would be to pass a by-law allowing roof sspace to be used for these purposes (and nly those purposes) provided the relevant owners signed an agreement that they are responsible for relevant maintenace and repairs related to the installations. That way you won't get, say, a new owner coming in and saying that air-con is on common property therefore the Owners Corp has to fix it when it breaks down. Anybody else with any thoughts?
Jimmy