Where do I measure my bottom floor to meet BFE requirements?

How to measure your bottom (lowest) floor and whether your home meets the BFE requirements is determined by your community’s building codes and floodplain management regulations, and the flood zone in which your home is located.

The term “lowest floor” is defined by the NFIP and building codes. It refers to the portion of the building that is raised above the ground on an elevated foundation. In Zone A, the elevation of the “lowest floor” is measured at the top of the floor of the elevated building. In Zone V, the elevation is measured at the bottom of the lowest horizontal structural member (beam) that supports the elevated building. 

To comply with the NFIP and building codes, a building must have its lowest floor elevated to or above the specified elevation, usually the BFE or higher.  The only way to know for sure if your home is elevated high enough to comply with the requirements is to have a licensed surveyor prepare an Elevation Certificate.  If your home was built in accordance with floodplain management rules in effect at the time it was constructed, your community may have a record of the surveyed information.

References: FEMA. 2012. Quick Reference Guide: Comparison of Select NFIP and Building Code Requirements for Special Flood Hazard Areas. Washington, DC. March 2012.

Last updated November 16, 2021