42-234.2 Specific Standards

In all Special Flood Hazard Areas where BFE data has been provided, as set forth in this Subpart A, the following provisions in addition to those required in §42-234.1 (General Standards) are required:

  1. Residential Construction. New construction and substantial improvement of any residential structure (including manufactured/mobile homes) shall have the reference level, including basement, elevated no lower than the Regulatory Flood Protection Elevation.
  2. Nonresidential Construction. New construction and substantial improvement of any nonresidential structure shall have the reference level, including basement, elevated no lower than the Regulatory Flood Protection Elevation. Structures located in A, AE and AO Zones may be flood proofed to the Regulatory Flood Protection Elevation in lieu of elevation provided that all areas of the structure, together with attendant utility and sanitary facilities, below the required flood protection elevation are watertight with walls substantially impermeable to the passage of water, using structural components having the capability of resisting hydrostatic and hydrodynamic loads and the effect of buoyancy. For AO Zones, the flood proofing elevation shall be in accordance with §42-234.7 (Standards for Areas of Shallow Flooding (Zone AO)). A registered professional engineer or architect shall certify that the flood proofing standards of this subsection are satisfied. Such certification shall be provided to the Floodplain Administrator as set forth in §42-349 (Floodplain Development Permits) C (2) (Certification Requirements), along with operational plan and the maintenance and inspection plan.
  3. Manufactured/Mobile Homes. No manufactured/mobile homes shall be permitted except replacement manufactured/mobile homes in an existing manufactured home park, existing manufactured home subdivision, or replacement manufactured/mobile homes on an individual parcel, provided the following conditions are met:
    1. Manufactured/mobile homes shall be elevated so that the reference level of the manufactured/mobile home is no lower than the Regulatory Flood Protection Elevation.
    2. Manufactured/mobile homes shall be securely anchored to an adequately anchored foundation to resist flotation, collapse, and lateral movement in accordance with the State of North Carolina Regulations for Manufactured Homes adopted by the Commissioner of Insurance pursuant to NCGS §143-143.15. Additionally, when the elevation would be met by an elevation of the chassis 36 inches or less above the grade at the site, the chassis shall be supported by reinforced piers or engineered foundation system. When the elevation of the chassis is above 36 inches in height, an engineering certification is required.
    3. All enclosures or skirting shall be in accordance with §42-234.2 (Specific Standards) D (Elevated Structures).
    4. An evacuation plan must be developed for evacuation of all residents of all substantially improved or substantially damaged manufactured/mobile home parks or subdivisions located within flood prone areas. This plan shall be filed with and approved by the Floodplain Administrator and the local Emergency Management coordinator.
  4. Elevated Structures. Enclosed areas, of new construction or substantially improved structures, which are below the Regulatory Flood Protection Elevation shall:
    1. Not be designed to be used for human habitation, but shall only be used for parking of vehicles, structure access, or limited storage of maintenance equipment used in connection with the premises. Access to the enclosed area shall be the minimum necessary to allow for parking of vehicles (garage door) or limited storage of maintenance equipment (standard exterior door) or entry to the living area (stairway or elevator). The interior portion of such enclosed area shall not be partitioned or finished into separate rooms, except to enclose storage areas;
    2. Be constructed entirely of flood resistant materials at least to the Regulatory Flood Protection Elevation;
    3. Include, in Zones A, AO and AE, flood openings to automatically equalize hydrostatic flood forces on walls by allowing for the entry and exit of floodwaters. To meet this requirement, the openings must either be certified by a professional engineer or architect or meet or exceed the following minimum design criteria;
      1. Provide a minimum of two (2) openings on different sides of each enclosed area subject to flooding;
      2. The total net area of all openings must be at least one (1) square inch for each square foot of each enclosed area subject to flooding;
      3. If a structure has more than one (1) enclosed area, each area must have flood openings to allow floodwater to automatically enter and exit;
      4. The bottom of all required openings shall be no higher than one (1) foot above the adjacent grade; and,
      5. Flood openings may be equipped with screens, louvers, or other opening coverings or devices provided they permit the automatic flow of floodwaters in both directions.

Foundation enclosures made of flexible skirting are not considered enclosures for regulatory purposes, and, therefore, do not require openings. Masonry or wood skirting, regardless of structural status, is considered an enclosure and requires openings as outlined above.

  1. Additions/Improvements.
    1. Additions and/or improvements to pre-FIRM structures where the addition and/or improvements in combination with any interior modifications to the existing structure are:
      1. Not a substantial improvement, the addition and/or improvements must be designed to minimize flood damages and must not be any more nonconforming than the existing structure.
      2. A substantial improvement, both the existing structure and the addition and/or improvements must comply with the standards for new construction.
    2. Additions to post-FIRM structures with no modifications to the existing structure other than standard door in the common wall shall require only the addition to comply with the standards for new construction.
    3. Additions and/or improvements to post-FIRM structures where the addition and/or improvements in combination with any interior modifications to the existing structure are:
      1. Not a substantial improvement, the addition and/or improvements only must comply with the standards for new construction.
      2. A substantial improvement, both the existing structure and the addition and/or improvements must comply with the standards for new construction.
    4. Where a fire wall or independent perimeter load-bearing wall is provided between the addition and the existing structure, the addition(s) shall be considered a separate structure and only the addition must comply with the standards for new construction.
  2. Recreational Vehicles. Recreational vehicles (RVs) shall either:
    1. Be on site for fewer than 180 consecutive days and be fully licensed and ready for highway use (a recreational vehicle is ready for highway use if it is on its wheels or jacking system, is attached to the site only by quick disconnect type utilities, and has no permanently attached additions); or
    2. Meet all the requirements for new construction. (See also §42-61 (Supplemental Requirements to the Table of Permitted and Special Uses) SR 4.15 (Recreational Vehicle Park).
  3. Temporary Nonresidential Structures. Prior to the issuance of a Floodplain Development Permit for a temporary structure, applicants must submit to the Floodplain Administrator a plan for the removal of such structure(s) in the event of a hurricane, flash flood or other type of flood warning notification. The following information shall be submitted in writing to the Floodplain Administrator for review and written approval:
    1. A specified time period for which the temporary use will be permitted, time specified may not exceed three (3) months, renewable up to one (1) year;
    2. The name, address, and phone number of the individual responsible for the removal of the temporary structure;
    3. The timeframe prior to the event at which a structure will be removed (i.e. minimum of 72 hours before landfall of a hurricane or immediately upon flood warning notification);
    4. A copy of the contract or other suitable instrument with the entity responsible for physical removal of the structure insuring the availability of removal equipment when needed; and
    5. Designation, accompanied by documentation, of a location outside the Special Flood Hazard Area to which the temporary structure will be moved.
  4. Accessory Structures. When accessory structures (sheds, detached garages, etc.) are to be placed within a Special Flood Hazard Area, the following criteria shall be met:
    1. Accessory structures shall not be used for human habitation (including working, sleeping, living, cooking or restroom areas);
    2. Accessory structures shall not be temperature controlled;
    3. Accessory structures shall be designed to have low flood damage potential;
    4. Accessory structures shall be constructed and placed on the structure site so as to offer the minimum resistance to the flow of floodwaters;
    5. Accessory structures shall be firmly anchored in accordance with §42-234.1 (General Standards) B(1);
    6. All service facilities such as electrical and heating equipment shall be installed in accordance with 42-234.1 (General Standards) B(2);
    7. Flood openings to facilitate automatic equalization of hydrostatic flood forces shall be provided below Regulatory Flood Protection Elevation in conformance with §42-234.2 (Specific Standards) D (Elevated Structures) (3);
    8. An accessory structure with a footprint less than 150 square feet does not require an elevation or flood proofing certificate (a Floodplain Development Permit is still required). Elevation or flood proofing certifications are required for all other accessory structures in accordance with §42-349 (Floodplain Development Permits) C (2) (Certification Requirements).