Flood Openings in Basement Walls Can Save on Insurance Costs
Ideally, you would never want to buy or build a home in a Flood Zone. But it happens.
The National Flood Insurance Program (NFIP) Regulations and Building Codes require that any residential building constructed in Flood Zone Type A have the lowest floor, including basements, elevated to or above the Base Flood Elevation (BFE). And some of these details can save you money on both insurance and energy use.
Flood Vent Requirements
Enclosed areas (enclosures) are permitted under elevated buildings provided that they meet certain use restrictions and construction requirements such as the installation of flood vents to allow for the automatic entry and exit of flood waters.
As used by the NFIP, an “enclosure” is an area that is enclosed on all sides by walls. Several examples of enclosures that require openings are described below:
- Solid perimeter foundation walls (crawlspaces or under-floor spaces)
- Solid perimeter foundation walls (below-grade crawlspaces)
- 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)
FEMA has this to say on the topic: "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. If the walls are “load-bearing” walls that support the elevated building, failure of the walls may result in damage to, or collapse of, the building. To address this concern, the NFIP (National Flood Insurance Program) regulations require that enclosure walls contain openings that will allow for the automatic entry and exit of floodwaters. These openings allow floodwaters to reach equal levels on both sides of the walls, thereby lessening the potential for damage caused by a difference in hydrostatic loads on opposite sides of the walls. In A zones, the requirement for flood openings applies to all enclosed areas below new elevated buildings and below substantially improved buildings."