During a design-level flood, storm, wind, or erosion event, a home owner should expect the following from a "successful" coastal building

• The building foundation must remain intact and functional.
• The envelope (walls, openings, roof, and lowest floor) must remain structurally sound and capable of minimizing penetration by wind, rain, and debris.
• The lowest floor elevation must be sufficient to prevent floodwaters from entering the elevated building envelope during the design event.
• The utility connections (e.g., electricity, water, sewer, natural gas) must remain intact or be restored easily.
• The building must be accessible and usable following a design-level event.
• Any damage to enclosures below the Design Flood Elevation (DFE)* must not result in damage to the foundation, the utility connections, or the elevated portion of the building.

Because of the additional hazard associated with wave action in V zones and in A zones in coastal areas, it is recommended that the minimum elevation requirements of the NFIP be exceeded in these areas:

• It is recommended that the bottom of the lowest horizontal structural member of V-zone buildings be elevated 1 foot or more above the Base Flood Elevation (BFE), i.e., add freeboard.
• It is recommended that the lowest horizontal structural member of A-zone buildings in coastal areas be elevated 1 foot or more above the BFE (i.e., add freeboard).

If the lowest enclosed area is used for anything other than parking of vehicles, building access, or storage, the floor of that area is considered the lowest floor. This will violate NFIP requirements and drastically increase flood insurance premiums.

• Note that any below-BFE finished areas, including foyers, will violate NFIP requirements, sustain unreimbursable flood damage, and increase flood insurance premiums.
• The floor of a basement (where "basement" means the floor is below grade on all sides) will always be the lowest floor, regardless of how the space is used.
• Walls of enclosed areas below the BFE must meet special requirements in coastal areas (see Fact Sheet No. 27).

As part of the agreement for making flood insurance available in a community, the National Flood Insurance Program (NFIP) requires the community to adopt a floodplain management ordinance that specifies minimum design and construction requirements. Those requirements include a certification of the structural design and the methods of construction. Specifically, NFIP regulations and local floodplain management ordinances require that:

1. a registered professional engineer or architect shall develop or review the structural design, specifications, and plans for the construction, and
2. a registered professional engineer or architect shall certify that the design and methods of construction to be used are in accordance with accepted standards of practice for meeting the following criteria:
   • the bottom of the lowest horizontal structural member of the lowest floor (excluding the pilings or columns) is elevated to or above the Base Flood Elevation (BFE); and
   • the pile or column foundation and structure attached thereto is anchored to resist flotation, collapse, and lateral movement due to the effects of wind and water loads acting simultaneously on all building components. Water loading values used shall be those associated with the Base Flood. Wind loading values used shall be those required by applicable state or local building standards.
     
   The community, through its inspection procedures, will verify that the building is built in accordance with the certified design.

The single most common and costly siting mistake made by designers, builders, and owners is failing to consider future erosion and slope stability when an existing coastal home is purchased or when land is purchased and a new home is built. Purchase decisions—or siting, design, and construction decisions — based on present-day shoreline conditions often lead to future building failures.

Homes in many coastal areas are often exposed to winds in excess of 90 mph (3-second peak gust). Choose building materials (e.g., roof shingles, siding, windows, doors, fasteners, and framing members) that are designed for use in high-wind areas.

Loads acting on a building follow many paths through the building and must eventually be resisted by the ground, or the building will fail.

• Loads accumulate as they are routed through key connections in a building.
• Member connections are usually the weak link in a load path.
• Failed or missed connections cause loads to be rerouted through unintended load paths.