§ 62-4062. Specific standards.

In all areas of special flood hazard where base flood elevation data has been provided as set forth in section 62-4005 or section 62-4031(6), the following provisions are required:

(1)

Residential construction. New construction and substantial improvement of any residential structure shall have the lowest floor, including basement, elevated to a minimum of 12 inches above the base flood elevation. No portion of the structure, excluding the foundation, shall be below the base flood elevation. Should solid foundation perimeter walls be used to elevate a structure, openings sufficient to facilitate the automatic equalization of hydrostatic flood forces on walls shall be provided in accordance with standards of subsection (3).

(2)

Nonresidential construction. New construction and substantial improvement of any commercial, industrial or nonresidential structure shall either have the lowest floor, including basement, elevated to a minimum of 12 inches above the base flood elevation, or, together with attendant utility and sanitary facilities, be floodproofed to a minimum of one-foot above the base flood elevation, such that the structure is watertight with walls substantially impermeable to the passage of water and with structural components having the capability of resisting hydrostatic and hydrodynamic loads, the effects of buoyancy and anticipated debris impact forces. A professional engineer or architect licensed to practice in the state shall certify that the standards of this subsection are satisfied. Such certification shall be provided to the official as set forth in section 62-4032(5).

(3)

Elevated buildings. New construction and substantial improvements of elevated buildings that include fully enclosed areas formed by foundation and other exterior walls below the lowest floor shall be designed to preclude finished living space and designed to allow for the entry and exit of floodwaters to automatically equalize hydrostatic flood forces on exterior walls.

a.

Designs for complying with this requirement must either be certified by a professional engineer or architect or meet the following minimum criteria:

1.

A minimum of two openings shall be provided for each enclosed area subject to flooding, on different sides of each enclosed area if practicable, 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; and

3.

Openings may be equipped with screens, louvers, valves or other coverings or devices provided they permit the automatic flow of floodwaters in both directions.

b.

Electrical, plumbing and other utility connections are prohibited below the base flood elevation.

c.

Access to the enclosed area shall be the minimum necessary to allow for parking of vehicles (garage door) or limited storage of maintenance equipment used in connection with the premises (standard exterior door) or entry to the living area (stairway or elevator).

(4)

Manufactured homes and recreational vehicles.

a.

All manufactured homes to be placed or substantially improved on individual lots or parcels, or in expansions to existing manufactured home parks or subdivisions, or in substantially improved manufactured home parks or subdivisions, or which have incurred "substantial damage" as a result of a flood, must meet all requirements for new construction, including elevation and anchoring requirements. Within special flood hazard areas, manufactured homes shall be elevated on a permanent foundation such that the lowest floor of the manufactured home and all appurtenant building equipment is a minimum of 12 inches above the base flood elevation, and be securely anchored to an adequately anchored foundation system in accordance with the following specific requirements:

1.

Over-the-top ties shall be provided at each end of the manufactured home, with one additional tie per side at an intermediate location on manufactured homes less than 50 feet long and one additional tie per side for manufactured homes 50 feet long or longer;

2.

Frame ties shall be provided at each corner of the home, with four additional ties per side at intermediate points for manufactured homes less than 50 feet long and one additional tie for manufactured homes 50 feet long or longer;

3.

All components of the anchoring system shall be capable of carrying a force of 4,800 pounds; and

4.

Any additions to the manufactured home shall be similarly anchored.

b.

Additional requirements for manufactured homes are as follows:

1.

All manufactured homes to be placed or substantially improved on sites in an existing manufactured home park or subdivision must be elevated so that:

i.

The lowest floor of the manufactured home and all appurtenant building equipment is elevated a minimum of 12 inches above the base flood elevation; or

ii.

The manufactured home chassis is supported by reinforced piers, or other foundation elements of at least an equivalent strength, of no less than 36 inches in height above grade, whichever is higher.

iii.

The manufactured home must be securely anchored to the adequately anchored foundation system to resist flotation, collapse and lateral movement.

2.

For new manufactured home parks and subdivisions; for expansions to existing manufactured home parks and subdivisions; for existing manufactured home parks and subdivisions where the repair, reconstruction or improvement of the streets, utilities and pads equals or exceeds 50 percent of the value of the streets, utilities and pads before the repair, reconstruction or improvement has commenced; and for manufactured homes not placed in a manufactured home park or subdivision, the following are required:

i.

Stands or lots shall be elevated on compacted fill so that the lowest floor of the manufactured home and all appurtenant building equipment will be a minimum of 12 inches above the base flood elevation; or

ii.

The manufactured home chassis shall be supported by reinforced piers, or other foundation elements of at least an equivalent strength, so that the lowest floor and all appurtenant building equipment will be elevated a minimum of 12 inches above the base flood elevation.

iii.

Manufactured homes shall be securely anchored to an adequately anchored foundation system in accordance with the provisions of subsection (4)a.;

iv.

Adequate surface drainage and access for a hauler shall be provided; and

v.

In the instance of elevation on pilings, lots shall be large enough to permit steps, piling foundations shall be placed in stable soil no more than ten feet apart, and reinforcement shall be provided for pilings more than six feet above the ground level.

c.

All recreational vehicles placed on sites must either:

1.

Be fully licensed and ready for highway use; or

2.

Meet all the requirements for new construction, including the anchoring and elevation requirements of subsection (4)a. or (4)b.

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 security devices, and has no permanently attached structures.

d.

All new manufactured home parks and subdivisions located within an area of special flood hazard shall file an evacuation plan indicating alternate vehicular access and escape routes with the county emergency management director at the earliest possible date.

(5)

Floodways. Located within areas of special flood hazard established in section 62-4005 are areas designated as floodways. Since the floodway is an extremely hazardous area due to the velocity of floodwater, which carries debris and potential projectiles and has erosion potential, the following provisions shall apply:

a.

Encroachments are prohibited, including fill, new construction, substantial improvements and other developments, unless certification, with supporting technical data, by a professional engineer licensed to practice in the state is provided demonstrating that encroachments shall not result in any increase in flood levels during occurrence of the base flood discharge.

b.

If subsection (5)a. is satisfied, all new construction and substantial improvements shall comply with all applicable flood hazard reduction provisions of section 62-4061 and this section.

c.

The placement of manufactured homes (mobile homes) is prohibited, except in an existing manufactured home (mobile home) park or subdivision. A replacement manufactured home may be placed on a lot in an existing manufactured home park or subdivision provided the anchoring standards of section 62-4061(2) and the elevation standards of subsection (1) and the encroachment standards of subsection (5)a. are met.

(6)

Coastal high-hazard areas (V zones). These areas have special flood hazards associated with wave wash. Therefore, the following provisions shall apply:

a.

All buildings or structures shall be located landward of the reach of the mean high tide.

b.

All new construction and substantial improvements shall be elevated so that the bottom of the lowest horizontal structural member of the lowest floor (excluding the pilings or columns) is elevated to a minimum of 12 inches above the base flood elevation, with all space below the lowest supporting member either open and free of obstruction, or constructed with non-supporting breakaway walls as provided for in subsection (6)h., or enclosed by open wood lattice-work or insect screening as provided in subsection (6)m.

c.

All new construction and substantial improvements shall be securely anchored on pilings or columns when any portion of the first-floor level is located at or below the 100-year base flood elevation level as established on the flood insurance rate map. The elevation of the first-floor level shall be based upon technical reports, survey, plats and other data certified by a professional engineer or architect licensed to practice in the state and provided by the applicant for the permit.

d.

Pilings or columns used as structural support and structures attached thereto shall be designed and 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 shall be those required by applicable state or local building standards.

e.

Compliance with the provisions contained in subsections (6)a., (6)b., (6)c. and (6)d. shall be certified to by a professional engineer or architect licensed to practice in the state.

f.

There shall be no fill used as a structural support.

g.

There shall be no alteration of sand dunes or mangrove stands which would increase potential flood damage.

h.

Breakaway walls shall only be allowed below the base flood elevation, provided they are not part of the structural support of the building and are designed so as to break away, under abnormally high tides or wave action, without damage to the structural integrity of the building on which they are to be used. Breakaway walls shall have a design safe loading resistance of not less than ten and no more than 20 pounds per square foot.

i.

If breakaway walls are utilized, such enclosed spaces shall be usable solely for parking of vehicles, building access or limited storage.

j.

Prior to construction, plans for any structure that will have breakaway walls must be submitted to the building official for approval.

k.

Any alteration, repair, reconstruction or improvement to a structure started after the enactment of the initial ordinance from which this section is derived shall not enclose the space below the lowest floor unless breakaway walls are used as provided for in subsection (6)h.

l.

All buildings or structures seaward of the county coastal construction control line shall be located and constructed in accordance with article XII or other applicable ordinances.

m.

Open wood lattice-work or insect screening shall be allowed below the lowest floor, provided it is not part of the structural support of the building and is designed so as to break away, under wind and water loads, without damage to the structural integrity of the building on which it is to be used, and provided the following design specifications are met:

1.

No solid walls shall be allowed; and

2.

Material shall consist of open wood lattice-work or mesh screening only.

n.

If lattice-work or screening is utilized, such enclosed space shall not be designed to be used for human habitation, but shall be designed to be used only for parking of vehicles, building access or limited storage.

o.

Prior to construction, plans for any structures that will have lattice-work or screening must be submitted to the building official for approval.

p.

Any alteration, repair, reconstruction or improvement to a structure shall not enclose the space below the lowest floor except with lattice-work or screening, as provided for in subsections (6)m., (6)n. and (6)o.

(7)

Streets and roads. All streets, roads, alleys or other rights-of-way constructed within areas of special flood hazard shall have the crown of such right-of-way elevated, at a minimum, to the higher of:

a.

Five feet three inches above sea level.

b.

An elevation not lower than the base flood elevation, where such base flood elevations have been established.

Nothing in this subsection shall in any way diminish the authority of the county to require such rights-of-way to be constructed at higher elevations than those set out in this subsection when, in its discretion, the county deems such higher elevations to be necessary.

(8)

Standards for areas of shallow flooding (AO zones). Located within the areas of special flood hazard established in section 62-4005 are areas designated as shallow flooding areas. These areas have special flood hazards associated with base flood depths of one to three feet, where a clearly defined channel does not exist and where the path of flooding is unpredictable and indeterminate; therefore, the following provisions apply:

a.

All new construction and substantial improvements of residential structures shall have the lowest floor, including basement, elevated to the depth number specified on the flood insurance rate map, in feet, above the highest adjacent finished grade. If no depth number is specified, the lowest floor, including basement, shall be elevated at least two feet above the highest adjacent finished grade.

b.

All new construction and substantial improvements of nonresidential structures shall:

1.

Have the lowest floor, including basement, elevated to the depth number specified on the flood insurance rate map, in feet, above the highest adjacent grade. If no depth number is specified, the lowest floor, including basement, shall be elevated at least two feet above the highest adjacent grade; or

2.

Together with attendant utility and sanitary facilities, be completely floodproofed to a minimum of 12 inches above that level so that any space below that level is watertight with walls substantially impermeable to the passage of water and with structural components having the capability of resisting hydrostatic and hydrodynamic loads and effects of buoyancy.

c.

All new construction and substantial improvements shall have adequate drainage paths provided around structures on slopes, to guide floodwaters around and away from structures.

(Code 1979, § 14-103; Ord. No. 01-66, § 1, 10-16-01; Ord. No. 02-09C, § 6, 2-26-02; Ord. No. 2014-14, § 1, 5-1-14)