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.


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.


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