Interpretation #9551
Published July 07, 2026
Original Request
- Code Version
- 2023
- Code
- RESIDENT
- Code Description
- Chapter
- 3
- Section
- R322
- Topic
- Construction in a flood hazard area
Question
Is it the intent of Section R322.1 to require compliance with the more restrictive flood zone when more than one zone exists, without exception?
Answer Published 07/01/2026 at 7:54 AM
No. The FBC requirements for Coastal A Zone do not apply if the entire footprint of the building is located landward of the Limit of Moderate Wave Action (LiMWA). R322.1 states that “Buildings and structures that are located in more than one flood hazard area shall comply with the provisions associated with the most restrictive flood hazard area.” FBCB 1612.1 includes the same, although phrased slightly differently.
Note that SFHAs between the LiMWA and the Zone V boundary (or shore if there is no Zone V boundary) are shown on FIRMs as “Zone AE.” However, the FBC defines those areas as Coastal A Zone. A building can be “entirely within the AE Zone” yet be entirely or partially in the Coastal A Zone if it is seaward of the LiMWA. A small number of communities have amended their regulations to include an “expanded” Coastal A Zone by applying a “setback” distance landward of the LiMWA.
Note that SFHAs between the LiMWA and the Zone V boundary (or shore if there is no Zone V boundary) are shown on FIRMs as “Zone AE.” However, the FBC defines those areas as Coastal A Zone. A building can be “entirely within the AE Zone” yet be entirely or partially in the Coastal A Zone if it is seaward of the LiMWA. A small number of communities have amended their regulations to include an “expanded” Coastal A Zone by applying a “setback” distance landward of the LiMWA.
Commentary
None.