Do Your Foundation Openings Meet FEMA Requirements?

The objective of the National Flood Insurance Program is to protect buildings that are constructed in flood hazard areas. 

According to the FEMA Technical Bulletin 1, Openings in Foundation Walls and Walls of Enclosures, NFIP regulations require that residential buildings in A zones to have the lowest floor elevated to or above the base flood elevation. Enclosed areas are permitted under elevated buildings, provided these areas meet certain requirements, including use of flood damage-resistant materials and installation of openings to allow for automatic entry and exit of floodwaters. Enclosres under buildings in V zones must meet the same requirements, with the exception that openings are not required and walls must be non-supporting breakaway walls, open lattice-work, or insect screening.

If enclosure walls are not designed with openings to relieve the pressure of standing or slow-moving water against them (called hydrostatic loads), the walls can be damaged or fail during a flood.

Crawl Space Foundation Openings Affect Flood Insurance Rates.

If crawl space foundation openings are not compliant with FEMA requirements, the floor of the crawl space  becomes the "lowest floor". This can result in higher flood insurance premiums, especially if the floor of the crawl space is more than a foot or two below the base flood elevation.

Enclosures That Require Openings

  -Solid perimeter foundation walls (crawl spaces or under floor spaces)

  -Solid perimeter foundation walls (with full-height under floor spaces)

  -Garages attached to elevated buildings

  -Enclosed areas under buildings elevated on open foundations in A zones

  -Enclosed areas with breakaway walls under buildings elevated on open foundations in A zones

  -Solid perimeter foundation walls on which manufactured homes are installed

  -Accessory structures (detached garages and storage sheds)

Engineered Openings, such as hydrostatic flood vents, that are certified by a registered design professional may be installed, provided they are issued an Evaluation Report by the ICC-ES. This report will need to be provided to the homeowner's insurance agent to document compliance.

To read or aquire the full FEMA Publication, Openings in Foundation Walls and Walls of Enclosures, Technical Bulletin / August 2008, click here

Contact Lowcountry Basement Systems for a Free Evaluation to determine if your foundation openings are FEMA compliant.