225 ILCS 316/23

(a) As used in this Section, "technical submissions" includes the designs, drawings, and specifications that establish the scope of a landscape architecture project; the standard of quality for materials, workmanship, equipment, and systems; and the studies and other technical reports and calculations prepared in the course of the practice of landscape architecture. (b) A registered landscape architect shall not exercise authority in preparing technical submissions that require the involvement of an architect, professional engineer, structural engineer, or professional land surveyor licensed in Illinois. (c) The registered landscape architect who has contract responsibility shall seal a cover sheet of the technical submissions and those individual portions of the technical submissions for which the registered landscape architect is legally and professionally responsible.