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

1. (1) a residential structure;
2. (2) a commercial structure that does not exceed three stories in height or 20,000 square feet in area; or
3. (3) an appurtenance to a structure described by Subdivision (1) or (2).

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