Substantial Improvement

Older buildings - built prior to December 31, 1974 - were grandfathered into the flood insurance program at their current heights. That grandfathered status expires once the building has been Substantially Improved; which means repaired or remodeled to 50% or more of the building’s market value.

Value

View these important points about the value of the building:

  • Only the building’s value, not the value of the entire property, is considered.
  • If a lot has multiple buildings, then only the value for the building being renovated is considered.
  • The 50% threshold is determined by the cumulative value of work performed during the past five years.

Elevation

Once the Substantial Improvement threshold has been, or will be reached, it usually requires the building be elevated to current height requirements above flood levels.

Building Permit

Each building needs its own Building Permit Application, even if they’re on the same lot. Only one set of plans is needed, not a set for each application.

Procedure Documents

  1. Additions Exert from Florida Building Code (PDF)
  2. Substantial Improvement Brochure
  1. What is the 50% rule?
  2. What's a "regulated flood zone?"
  3. How is the market value of my building determined in connection with the 50% rule?
  4. I believe my house is worth more than the Adjusted Property Appraiser's value, so my 50% threshold should be higher. How do I validate this?
  5. How is the value of improvements determined?
  6. Instead of elevating my home, can I dry floodproof it?
  7. Does the 5-year rule reset with a change of ownership?
  8. Instead of elevating my commercial building, may I dry floodproof it?
  9. How high does my building need to be elevated?
  10. My lot is above sea level, so how high on the lot must I raise my house?
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