As used in this chapter, unless the context otherwise requires: “Improvement” means any newly constructed single family dwelling unit, any conversion condominium unit being conveyed by the declarant and any fixture or structure which is made a part thereof at the time of construction or conversion by any building contractor, subcontractor or declarant; “purchaser” means the original buyer, his heirs or designated representatives, of any improved real estate; “real estate” means any fee simple estate; and “vendor” means any person engaged in the business of erecting or creating an improvement on real estate, any declarant of a conversion condominium, or any person to whom a completed improvement has been granted for resale in the course of his business.