Should costs for building materials purchased by the builder (myself) used for construction jobs be listed under "miscellaneous expenses?"

Line 22 of Schedule C, Supplies, would be a more appropriate place for this entry.  Really, the important thing isn’t so much where you report it, as that you do report it.

You should make sure that you’re not double-counting certain expenses. 

I read somewhere that materials used in the building process are not deductible....only tools.  Are there certain building material expenses that I should omit?  Thanks. 

Building materials used for the job would be supplies. See Publication 535 (2020), Business Expenses | Internal ...for the complete listing of what expenses are allowed.

See Self-Employed Individuals Tax Center for complete details.