Openings

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

Definition/Description

In A Zones, all new construction and substantial improvements may have fully enclosed areas below the lowest floor that are usable solely for vehicle parking, building access, or storage, in an area other than a basement, which are subject to flooding These enclosed areas must be designed to automatically equalize hydrostatic flood forces on exterior walls by allowing the entry and exit of floodwaters. Designs to meet this requirement must be certified or meet the following criteria:

1. A minimum of two openings having a total net area of not less than one square inch for every square foot of enclosed area subject to flooding,
2. The bottom of all openings shall be no higher than one foot above grade. Garage doors do not meet the National Flood Insurance Program (NFIP) minimum requirements for openings.

NFIP Requirement

• 60.3 - Criteria for land management and use
  • (a) (3) - Reasonably Safe from Flooding
  • (c) (5) Openings Requirement in A Zones

Guidance

• IS-9 Managing Floodplain Development Through The National Flood Insurance Program (NFIP) (pages 5-33 to 5-35)
• Openings in Foundation Walls and Walls of Enclosures (Technical Bulletin 1) (2008)

Related Keywords

• Certifications
• Enclosure
• Flood-Resistant Material
• Crawlspace
• Elevation