Elevating an Existing Home
If you live in Louisiana, your primary objective in raising a home is likely to be flood avoidance, even if you're not in an identified flood hazard area. Elevation is the most effective on-site method of reducing future flood damage. New buildings in designated flood hazard areas must have the lowest floor at or above the elevation of the base flood, the Base Flood Elevation (BFE).
Elevation is required when a building has been substantially damaged or is being substantially improved. If the improvement is an addition of a room on the side, the addition - and sometimes the entire structure - must meet the requirements imposed on new construction.
Substantial means the cost of improvements (or repairs) as a percentage of the market value of the structure before improvement (or before damage) exceeds some threshold value. The maximum threshold value allowed by FEMA is 50%; in some Louisiana communities' local governments have lowered the threshold to 40% or even 25%.If substantial improvement is not tracked cumulatively, the structure can be improved 40% this year, 30% next year, and so on - without triggering the substantial improvement provisions. If it is tracked cumulatively, the 30% improvement after a 40% improvement would exceed 50% and trigger the requirement to elevate.