So, all construction loans are non - reportable???
No that is not accurate. Refer to the commentary of REG C:
Paragraph 3(c)(3)
1. Temporary financing. Section 1003.3(c)(3) provides that closed-end mortgage loans or open-end lines of credit obtained for temporary financing are excluded transactions. A loan or line of credit is considered temporary financing and excluded under § 1003.3(c)(3) if the loan or line of credit is designed to be replaced by separate permanent financing extended by any financial institution to the same borrower at a later time.
2. Loan or line of credit to construct a dwelling for sale. A construction-only loan or line of credit is considered temporary financing and excluded under § 1003.3(c)(3) if the loan or line of credit is extended to a person exclusively to construct a dwelling for sale. See comment 3(c)(3)-1.ii through .iv for examples of the reporting requirement for construction loans that are not extended to a person exclusively to construct a dwelling for sale.