Which of the following documents does the contractor use to determine the quantities of materials needed for the contract?

The correct document that a contractor uses to determine the quantities of materials needed for a contract is the drawings. Drawings are a critical component of construction documents, as they provide detailed visual representations of the project. They include plans, elevations, sections, and other details that specify dimensions, materials, and construction methods.

By analyzing the drawings, a contractor can accurately calculate the amount of materials required for each aspect of the project. This ensures that there is an adequate supply of materials to complete the job efficiently, which is essential for maintaining timelines and budgets.

The other options serve different purposes. A warranty statement outlines the guarantees provided by the contractor regarding the quality of work and materials but does not contain information about quantities. General conditions establish the rights and responsibilities of each party involved in the contract, focusing more on the overall project management rather than specific material quantities. Addenda are modifications or clarifications to the original contract documents and can provide additional information, but they do not serve as the primary source for determining material quantities.