Terrebonne Parish, LA Hurricane Preparedness: Flood Elevation (2026)

Sec. 9-60 covers the coastal high hazard areas within Terrebonne Parish's special flood hazard zones, mapped as zones V1-30, VE, and V, which the code describes as subject to high velocity waters from tidal surges and hurricane wave wash. On top of every other Chapter 9 requirement, new construction and substantial improvements there must be elevated on pilings and columns so the bottom of the lowest horizontal structural member of the lowest floor sits at or above the minimum elevation required by the effective building code, the 2021 IBC as amended, with the piling or column foundation anchored to resist flotation, collapse, and lateral movement from combined wind and water loads.

A registered professional engineer or architect must certify the design. Space below the elevated floor has to stay open or use breakaway walls, open lattice, or insect screening rated to collapse under wind and water loads without damaging the structure above; a breakaway wall's design load has to fall between ten and twenty pounds per square foot unless an engineer certifies a higher-rated design that will still fail before the base flood load hits the elevated structure. Filling for structural support of buildings is banned outright, as is manmade alteration of sand dunes and mangrove stands that would raise flood damage potential.

Enclosed space below the lowest floor can only be used for vehicle parking, building access, or storage, never for human habitation, and any plans involving breakaway walls have to go to the floodplain administrator for approval before construction starts.