I have a brick outbuilding, around ~ 3.5mx2.5m in size. The equipment I want to store inside fit (power rack, barbell etc), but I am worried about preservation of the equipment (it is quite expensive stuff) since the outbuilding has occasional leaks and is not very dry. Other than plugging all the leaks, what kind of things do I need to do to the outbuilding so that metal things stored inside do not rust? Do I need some kind of dehumidifier or just heat it occasionally?