Except in the case of buildings that are unsafe and the demolition of which is required pursuant to the provisions of Chapter 26, Title C, Part I, Article 8, or its successor, of the New York City Administrative Code, no demolition permit shall be issued by the Department of Buildings for any development within the Subdistrict until:

(a)        the owner of the property has obtained a building application approval for the new development or enlargement; and

(b)        the owner shall have presented evidence of having a commitment from a domestic bank, insurance company or real estate investment company, for construction financing, which shall be in the form of a letter trust.