S40 - FEMA - Substantial Improvement and Substantial Damage rule
Kind: Federal regulation Group: Regulatory
URL: https://www.fema.gov/floodplain-management/financial-help/substantial-improvement-substantial-damage
Why this source was used
The FEMA “50% Rule” (44 CFR 59.1, 60.3) is triggered when renovation cost equals or exceeds 50% of the structure’s pre-project market value in a designated floodplain. Once triggered, the entire structure must be brought into compliance with current NFIP new-construction standards, including elevation to Base Flood Elevation. Costs are tracked cumulatively. This is a critical code-compliance escalation trigger unique to renovation and one of the most consequential regulatory thresholds a renovation project can hit.