For a small addition built to codes established in 1990, how high must it be elevated if the updated BFE is 6 feet?

In the context of floodplain management, the Base Flood Elevation (BFE) represents the minimum elevation to which floodwaters are expected to rise during a base flood event. When state or local floodplain regulations are updated, new constructions or substantial improvements, including additions, must often adhere to these updated standards.

For a small addition being constructed, if the updated BFE is at 6 feet, the elevation requirement typically dictates that the lowest floor of the building—whether it's a new structure or a substantial improvement—must be elevated to at least the BFE level. Given that the building codes from 1990 may differ from the current standards, the addition must now comply with the updated floodplain management requirements.

The elevation requirement would not only involve meeting the BFE itself but could include an additional freeboard level for safety. Freeboard is an added factor of height that provides an extra cushion against flooding. A common practice is to require buildings to be constructed at least 1 to 2 feet above the BFE to mitigate the risks of flooding, thus aligning adjusted elevation with best flood risk reduction practices.

Considering these factors, the requirement to elevate the small addition to at least 4 feet above grade represents a scenario where it is sufficiently higher than