In Walker v. Thornsberry (1979) 97 Cal. App. 3d 842, the product supplied by the manufacturer was a prefabricated metal restroom. The product was delivered to the jobsite in pieces that were bolted together and attached to a concrete foundation by employees of the manufacturer. The issue was whether the exemption of section 7045 applied to finished products even though substantial on-site work was conducted. The court noted that the manufacturer did not install the concrete foundation, rough plumbing or plumbing fixtures, stalls, roofing or painting. Because the manufacturer's employees only assembled the pieces and bolted the structure to the foundation, the court reasoned that their labor was merely incidental and that the activity was within the exemption of section 7045. (Id. at p. 847.)