A storage unit needs to be solid and secured, otherwise, what's the point? But different storage units have different levels of defence against one force that you might not have considered: the weather. Before you hire a storage unit, do you need to think about how weatherproof the unit will be?
Repel the Weather
Clearly, even the most basic storage unit needs to repel the weather—keeping out wind and rain. Weatherproofing doesn't technically require any effort on your part beyond choosing the most appropriate unit in the first place. It's not as though you need to make modifications to any unit you've hired, aside from some basic precautions.
One of these basic precautions is during extreme weather when your storage unit is semi-detached (external structure connected to other units, each with its own entrance). That garage door entrance should already contain weatherstripping to keep the rain out—but double-check this before you rent the space. A lack of weatherstripping (particularly the vinyl or rubber tubing at the base of the door) allows heavy rain to easily penetrate the unit.
However, rain isn't the type of moisture that should be most concerning. Relative humidity is the moisture in the air expressed as a percentage of moisture the air is capable of containing. Australia's relative humidity can be extreme, and this excess moisture can wreak havoc inside a sealed storage unit, damaging paper, warping wood and allowing mould and mildew to form.
Managing humidity inside a storage unit can be related to how you use the unit. Is it going to be sealed up for weeks or even months? Or will you be a regular visitor, opening up the unit every few days? If it's the latter option, there's not much to worry about. Your regular visits will air out the unit quite adequately, and you can even invest in a small dehumidifier to periodically turn on inside the unit. But what about when you have at-risk items inside the unit and don't plan to visit all that often?
Control the Climate
If humidity poses a threat to what you plan to store inside the unit, you need to avert this threat by choosing the right unit. It will cost a little more, but a climate-controlled unit has its relative humidity controlled via HVAC and insulation. Items are stored in the climate that will best preserve them.
Weatherproofing a storage unit isn't technically about changing anything, and is more about choosing a unit that's weatherproof enough to serve your needs. For more information about storage units, contact a local facility.