Existing Buildings
This is simpler to understand with an existing building that’s going to be elevated. It’s the distance from the ground to the Base Flood Elevation (BFE) level, plus up to a maximum of four additional feet. The BFE level differs by location; in some instances, buildings on a single lot may have different BFE levels if a flood zone line runs through the lot. Review How to Read Flood Maps for more information.
Flood Levels
Determining how high above ground the minimum flood level (BFE) is for any site can’t be determined until it’s known how high above sea level the land is at. The level of the grade is usually determined by obtaining an Elevation Certificate for the location or building from a land surveyor.
Examples
These examples include mathematical expressions. In the following examples the addition symbol (+) will be used and the equals symbol (=).
- Example 1: If an Elevation Certificate shows a building is located within an "AE-6 Inch flood zone, and the land is four-feet above sea level, then the BFE is two-feet above the ground (4 feet + 2 feet = 6 feet).
- Example 2: If an Elevation Certificate shows a building is located within an "AE-8 Inch flood zone, and the land is three-feet above sea level, then the BFE is five-feet above the ground (3 feet + 5 feet = 8 feet).
New Construction
There are now minimum elevation standards for new buildings. The Building Height Exception doesn’t being to be calculated until those minimums are exceeded. Given that the maximum exception is Base Flood Elevation (BFE) plus four-feet, a maximum three-feet of height exception is possible.
Examples
These examples include mathematical expressions. In the following examples the addition symbol (+) will be used and the equals symbol (=).
- Example 1: Where the minimum standard is BFE +1 foot, a building constructed to this height wouldn’t be eligible for any height exception.
- Example 2: Where the minimum standard is BFE +1 foot, a building constructed to BFE +2’, it would be eligible for a height exception of one-foot.
- Example 3: Where the minimum standard is BFE +1 foot, a building constructed to BFE +4’, it would be eligible for a height exception of three-feet.