R.I. Gen. Laws § 34-41-4.18: Substantial completion of units.

In the case of a sale of a time share interest unit where delivery of a public offering statement is required, a contract of sale may be executed, but no interest in that unit may be conveyed or finally transferred until the unit is substantially completed, as evidenced by a recorded certificate of substantial completion executed by an independent registered architect or engineer, or by issuance of a certificate of occupancy authorized by law.