Substantial Damage means the cost to repair a building in the SFHA to its “before damage” condition will equal or exceed 50% of the market value of the structure before the damage.
The determination applies to repairs from any source of damage, including flooding. There may be exceptions for designated historic structures and corrections of existing code violations, which should be outlined in the community’s floodplain ordinance.
Substantially Damaged buildings must meet the requirements in the community’s floodplain ordinance that apply to Substantial Improvements and new construction.
Substantial Improvement means the cost of repairs and improvements will equal or exceed 50% of the market value of the structure before the improvement.
Substantial Improvements must meet the same requirements that apply for new construction. There may be exceptions for designated historic structures and corrections of existing code violations.
FEMA Resources
Substantial Improvement (SI) /Substantial Damage (SD) Desk Reference (pdf)
Answers to Questions About Substantially Improved/Substantially Damaged Buildings (pdf)
FEMA's Substantial Damage Quick Guide
Substantial Damage Estimator
Substantial Damage Estimator
Other Resources
NH Flood Hazards Handbook and
checklist
An Introduction to SI & SD (OPD video)
Sample SI/SD Application Packet
Sample Guide for Property Owners
Making Substantial Damage Determinations (
video) (
slides)
Determining SD/SI – (2009 Powerpoint)
Quick Reference
SD Determination Process
- Identify that a determination needs to be made
- Communicate permit requirements to property owners.
- Verify the cost of repairs to the structure
- Verify the market value of the structure
- Make the determination and issue to the property owner.
- Ensure compliance with your ordinance through permitting process
SI Determination Process
- Review permit application to confirm determination needs to be made.
- Verify the cost of improvements to the structure.
- Verify the market value of the structure
- Make the SI determination and issue it to the property owner.
- Ensure compliance with your ordinance through permitting process
Flood Insurance and FEMA Grants
NFIP-insured property owners of buildings determined to be Substantially Damaged due to flooding are eligible for Increased Cost of Compliance (ICC) funds. See our Insurance page for more information.
For FEMA hazard mitigation grants, a cost-effectiveness methodology may apply for projects involving a Substantially Damaged building. Learn more on our
Mitigation and Resilience page.
Communities may also apply for
FEMA funds following a major disaster declaration to assist in administering and enforcing building and floodplain management codes. This includes the process of making SD determinations.