To add to what Randy and Joker already said, you might direct your investor to the CFPB's March 2016 construction webinar where they discuss how the waterfall applies from a construction loan perspective:
A creditor must disclose the purpose as refinance if the consumer intends to use the credit to construct a dwelling on real property that the consumer already owns and to satisfy an existing loan secured by that real property.
If the credit will be used to finance the initial construction of a dwelling on the property and will not be used for any purchase or refinance purpose, the creditor must disclose the purpose as construction.
While your situation is a bit different (not construction), the March 2016 webinar made it clear that previously owned dirt would exclude "purchase" as an option.
Adam Witmer, CRCM
All statements are my opinion, not those of my employer, and should not be taken as legal advice.www.compliancecohort.com