This subchapter applies only to contractors and workers preparing to construct, constructing, altering, repairing, extending, or demolishing:

(1) a residential structure;

(2) a commercial structure that does not exceed three stories in height or 20,000 square feet in area; or

(3) an appurtenance to a structure described by Subdivision (1) or (2).

Acts 1993, 73rd Leg., ch. 269, § 1, eff. Sept. 1, 1993.