Incomplete Design Documents Are the Primary Driver
The single largest generator of RFIs is incomplete structural drawings. When the EOR issues drawings with unresolved items — connection loads not shown, member sizes to be confirmed, openings in concrete not coordinated — every unresolved item becomes an RFI. Detailers cannot make engineering decisions; they can only request them. A project that kicks off on 70% complete design documents will generate significantly more RFIs than one that starts with a complete IFC package.
Connection Design Ambiguity
When the structural drawings don't clearly define who designed the connections — or what the governing loads are — every connection that isn't standard becomes an RFI. If the EOR says 'design by fabricator' without providing loads, the detailer must ask for loads. If the EOR shows a connection type without showing the required plate thickness, the detailer must ask. Connection-related RFIs are the most disruptive because they block drawing production on everything that uses that connection.
Coordination Gaps Between Disciplines
When structural drawings conflict with architectural, MEP, or civil drawings, the conflict must be resolved before detailing can proceed. Common conflicts: beam locations that conflict with ductwork routing, column locations that shift between structural and architectural plans, slab openings that require steel coping that isn't shown on structural drawings. These RFIs are not the detailer's fault — but they are the detailer's responsibility to identify and document.