Collier County Government offices will be closed Monday, May 27, 2019, in observance of Memorial Day.

Analysis of Substantial Improvement or Repair of Substantial Damage

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How To Determine Substantial Improvement According to FEMA's 50% Rule

What is Substantial Improvement and FEMA's 50% Rule?

Substantial Improvement is defined as any reconstruction, rehabilitation, addition, or other improvement of a structure, the cost of which equals or exceeds 50 percent of the market value of the structure before the "start of construction" of the improvement. This term includes structures which have incurred "substantial damage," regardless of the actual repair work performed.

Projects that are considered substantial improvement must meet current Florida Building Code, 6th Ed. (2017), as well as the provisions of the Collier County Flood Damage Prevention Ordinance.

Learn more from FEMA's Answers to Questions About Substantially Improved/Substantially Damaged Buildings brochure, dated August 2018 (published November 2, 2018).


Forms and Templates to Determine Substantial Improvement and Substantial Damage

The forms below are required to be submitted when the scope of work for a building permit includes reconstruction, rehabilitation, addition, or other improvement to the structure. These forms will assist in the determination of whether the scope of work will be a substantial improvement or repair of substantial damage.

Have Questions?
Please contact Howard Critchfield, Senior Engineer (239) 252-5858 or to set up an appointment to discuss your project. Please bring any related documents, such as elevation certificates, construction documents, estimates, insurance reports, and surveys to the meeting. 
Floodplain Management
To confirm flood zone and base flood elevation information, contact the Floodplain Management section at 239- 252-2942 or
Elevation Certificate
To check if an elevation certificate is available for a structure, visit this webpage and search by postal address:




Main Campus:  2800 North Horseshoe Drive, Naples, FL 34104

Phone: (239) 252-2400


Updated 04/29/2019