Are engineering fees hourly or fixed?

Engineering fees can be fixed, time-based, or a defined combination of both. A fixed fee fits a sufficiently bounded scope with known deliverables and assumptions. Hourly or other time-based billing can be more transparent when existing conditions, agency direction, or design changes are uncertain. A hybrid may fix core documents while treating added services separately. The contract should explain rates or fee logic, authorization, records, and limits; no fee structure transfers AHJ authority or permits work outside the engineer's competence.

The correct application of engineering fee structures starts with the actual project, not a generic promise. Confirm the jurisdiction, adopted code, design scope, existing conditions, required deliverables, and professional responsibility before relying on a conclusion. A responsible engineer documents assumptions and identifies information that still needs verification.

Project type, occupancy, existing construction, site conditions, code edition, agency requirements, and changes made after the original design can change the work. A concise answer is useful for orientation, but the signed or sealed project record must reflect the current scope and the authority's process.

• Confirm the authority having jurisdiction and current checklist
• Use current drawings, calculations, field evidence, and equipment information
• Separate engineering decisions from owner, architect, contractor, utility, and agency decisions
• Record assumptions, limitations, and questions requiring direct AHJ confirmation