For a completed large project, FEMA funds actual costs, and denies any cost not supported by documentation. If actual cost records aren’t readily available but the completed scope is well documented, FEMA can fund it on an estimate. For a completed small project, FEMA may accept your certification of costs instead of documentation and fund it on the estimate.
For large projects: actual cost documentation for everything claimed (invoices, payroll, equipment logs, contracts and proof of payment). If actual costs are not readily available, documentation that defines the completed scope well enough for an estimate. For small projects: your certification of costs, plus records kept on file in case you later claim a net small project overrun.
On completed work, the record is the project. Missing payroll, equipment logs or proof of payment mean denied costs, and a request for information you don’t answer in time becomes a determination memo you then have to appeal.