Paper products like important documents that may rot due to high humidity;
Electronics such as computers;
Home furnishings, especially antiques, that may suffer wood rot if stored in high humidity.
Furs (store in a cold environment during the summer months when not in use to prevent the oil loss from excessive heat and humidity, which causes the skin to harden); mattresses, dampness can destroy mattresses with mould growth and rust in the metal springs; and musical instruments such as pianos may be sensitive to changes in environmental conditions, especially humidity. They may get rusty and the wood can rot.
It’s more expensive, but if your stuff requires some sort of climate control to stay in top condition, choose a warehouse that offers it. Find out how the warehouse monitors the climate-controlled spaces, and inquire about an alarm system to warn if temperature or humidity are not at the correct levels, and if there is a back-up generator to deal with power outages.
Also, ask about temperature and humidity chart recorders or other devices to monitor the conditions in the controlled areas.
If you do not use climate-controlled storage facilities
, many companies exclude damage because of mould, high humidity or vermin, as these are considered normal risks of storage.