Common RFI topics: dimension conflicts between sheets, missing detail callouts, unclear material specifications, scope ambiguity at trade boundaries, conflicts between architectural and structural drawings.
Each RFI gets a number, a date, a description, and a response. Many GCs require subcontractors to submit RFIs through a specific tracking system (Procore, e-Builder, BlueSky); each carries a deadline for response.
At bid time, estimators sometimes need RFIs to clarify a scope item before pricing. Late RFIs that change scope mid-bid can justify a clarification or assumption in the bid letter.