Breakaway Wall

The purpose of this page is to define breakaway walls, a commonly used term in floodplain management.

Definition/Description

A wall that is not part of the structural support of the building and is intended through its design and construction to collapse under specific lateral loading forces, without causing damage to the elevated portion of the building or supporting foundation system. Any walls below the lowest floor in a building in a V Zone should give way under wind and water loads without causing collapse, displacement, or other damage to the elevated portion of the building or the supporting pilings or columns.

NFIP Requirement

• 59.1 - Definition
• 60.3 - Flood plain management criteria for flood-prone areas
  • (e)(4) - V Zone Elevation Requirement
  • (e)(5) Free of Obstruction Requirement

Guidance

• IS-9 Managing Floodplain Development Through The National Flood Insurance Program (NFIP) (pages 5-50, 5-51)
• 9-99, Design and Construction Guidance for Breakaway Walls Below Elevated Coastal Buildings (Technical Bulletin 9) (2008)
• Flood Damage-Resistant Materials Requirements (Technical Bulletin 2) (2008)
• Free-Of-Obstruction Requirements (Technical Bulletin 5) (2008)

Related Keywords

• Coastal High Hazard Area
• Hydrodynamic Forces
• Obstructions

Special Topic Resources

• Certification Requirements  
  • Design and Construction Guidance for Breakaway Walls Below Elevated Coastal Buildings (Technical Bulletin 9) (2008) p. 4
•  Solid Breakaway Wall Panels  
  • Coastal Construction Manual (FEMA 55) 12.4.6 Breakaway Wall Enclosures

Supplemental Information for Breakaway Wall

Communities may wish to limit the area enclosed by solid breakaway walls to less than 300 square feet because:

1. Flood insurance rates increase dramatically for enclosures larger than 300 square feet.
2. Larger areas encourage conversion to habitable living areas, which are difficult to detect and enforce as violations.