If you have purchased a condo or co-op, the bank will require insurance to protect its investment in your home. You may, however, need more insurance to cover your personal items, liability or fees that may be charged to you regarding shared areas of the building like the lobby.
You will need two separate policies to protect your investment:

1. Your own insurance policy.  
   This provides coverage for your personal possessions, structural improvements to your apartment and additional living expenses if you are the victim of fire, theft or other disaster listed in your policy. You also get liability protection.
2. A "master policy" provided by the condo/co-op board.  
   This covers the common areas you share with others in your building like the roof, basement, elevator, boiler and walkways for both liability and physical damage.

To adequately insure your apartment, it is important to know which structural parts of your home are covered by the condo/co-op association and which are not. You can do this by reading your association’s bylaws and/or proprietary lease. If you have questions, talk to your condo association, insurance professional or family attorney.
Source: iii.org

---