To be considered "substantially damaged," a building in a flood hazard area must meet a set of criteria and comply with certain requirements.
FEMA uses the term "substantial damage" to trigger a review of compliance with building code requirements applied to damaged buildings in flood hazard areas.
Those requirements are:
- The current community floodplain management regulations, and
- The flood provisions of the International Codes.
Substantial damage does not trigger all building code requirements for new construction.
Buildings must comply with flood provisions when the cost of restoring the structure to its before-damaged condition would equal or exceed 50 percent of the market value of the structure before the damage occurred.
The Substantial Damage Estimator Tool
FEMA developed the tool to assist state and local officials in estimating substantial damage for residential and non-residential structures per the National Flood Insurance Program requirements adopted by the communities. The tool assesses damage caused by flood, wind, wildfire, seismic and other events.
The above Version 3.0 of the tool enhances three key areas of performance, data accessibility and usability while improving the user experience with multiple enhancements that address user feedback.
Using the Tool
Communities participating in the National Flood Insurance Program are required to determine if any damage meets the criteria for Substantial Damage when the damage is to a structure located in a mapped 100-year floodplain.
The tool also determines if a substantially damaged structures in a mapped 100-year floodplains requires additional repairs to meet Substantial Improvement criteria. Improvements may include rehabilitation, remodeling, and lateral or vertical additions.
User Manuals & Guides
Understand the proper uses and guidance for the SDE 3.0 tool.
Follow the installation guide for the SDE 3.0 tool.
Follow FEMA P-758, Substantial Improvement Substantial Damage Desk Reference to implement National Flood Insurance Program (NFIP) requirements for Substantial Improvement/Substantial Damage.
Frequently Asked Questions
Have additional questions? Download the Answers to Questions About Substantially Improved/Substantially Damaged Buildings in FEMA P-213.
Or read the frequently asked questions about the SDE 3.0 tool online.
Forms & Checklists
Utilize the SDE 3.0 forms.
One-Pagers & Best Practices
Learn more about the SDE tool in the SDE 3.0 fact sheet.
Access the job aid to better understand the concept of Substantial Damage (SD) and how to determine if a building meets this criterion.
Read the best practices for FEMA P-784.