Is indirect materials same thing as factory overhead?

Answer 1

Not really.
Factory overhead is there no matter what. If you own the building, you need to pay the mortgage, property taxes, phone bill, etc. None of these lead directly to the production of goods. Even if you produce nothing for a month, you would still incur these expenses.

Indirect materials are only used in the production of your goods. They are too minimal to keep track of directly. These are typically small things like screws, nails, glue, or paint. You may be able to apply a formula to come up with a base cost to apply to your end products, but you will never assign costs based on the individual components (Example 300 pounds of nails were used on a house so you charge their cost to the house).