§ 275-14. Specific standards.

In all areas of special flood hazard where base flood elevation data has been provided as set forth in § 275-6, Basis for establishing areas of special flood hazard, and § 275-12B, Use of other base flood and floodway data, the following standards are required:

A. 

Residential construction. New construction and substantial improvements of any residential structure shall:

(1) 

Have the lowest floor, including basement or cellar, elevated to or above the base flood elevation.

(2) 

Have fully enclosed areas below the lowest floor that are subject to flooding designed to automatically equalize hydrostatic flood forces on exterior walls by allowing for the entry and exit of floodwaters. Designs for meeting this requirement must either be certified by a licensed professional engineer or architect or meet or exceed the following minimum criteria:

(a) 

A minimum of two openings having a total net area of not less than one square inch for every square foot of enclosed area subject to flooding shall be provided;

(b) 

The bottom of all such openings shall be no higher than one foot above the lowest adjacent finished grade; and

(c) 

Openings may be equipped with louvers, valves, screens or other coverings or devices, provided that they permit the automatic entry and exit of floodwaters.

B. 

Nonresidential construction. New construction and substantial improvements of any commercial, industrial or other nonresidential structure, together with attendant utility and sanitary facilities, shall either have the lowest floor, including basement or cellar, elevated to or above the base flood elevation, or be floodproofed to the base flood level.

(1) 

If the structure is to be elevated, fully enclosed areas below the base flood elevation shall be designed to automatically (without human intervention) allow for the entry and exit of floodwaters for the purpose of equalizing hydrostatic flood forces on exterior walls. Designs for meeting this requirement must either be certified by a licensed professional engineer or a licensed architect or meet the following criteria:

(a) 

A minimum of two openings having a total net area of not less than one square inch for every square foot of enclosed area subject to flooding;

(b) 

The bottom of all such openings shall be no higher than one foot above the lowest adjacent finished grade; and

(c) 

Openings may be equipped with louvers, valves, screens or other coverings or devices, provided that they permit the automatic entry and exit of floodwaters.

(2) 

If the structure is to be floodproofed:

(a) 

A licensed professional engineer or architect shall develop and/or review structural design, specifications and plans for the construction and shall certify that the design and methods of construction are in accordance with accepted standards of practice to make the structure watertight, with walls substantially impermeable to the passage of water and with structural components having the capability of resisting hydrostatic and hydrodynamic loads and the effects of buoyancy.

(b) 

A licensed professional engineer or licensed land surveyor shall certify the specific elevation (in relation to mean sea level) to which the structure is floodproofed.

(3) 

The local administrator shall maintain on record a copy of all such certificates noted in this section.

C. 

Construction standards for areas of special flood hazard without base flood elevations.

(1) 

New construction or substantial improvements of structures, including manufactured homes, shall have the lowest floor (including basement) elevated to at least two feet above the highest adjacent grade next to the proposed foundation of the structure.

(2) 

Fully enclosed areas below the lowest floor that are subject to flooding shall be designed to automatically (without human intervention) allow for the entry and exit of floodwaters for the purpose of equalizing hydrostatic flood forces on exterior walls. Designs for meeting this requirement must either be certified by a licensed professional engineer or a licensed architect or meet the following criteria:

(a) 

A minimum of two openings having a total net area of not less than one square inch for every square foot of enclosed area subject to flooding;

(b) 

The bottom of all such openings shall be no higher than one foot above the lowest adjacent finished grade; and

(c) 

Openings may be equipped with louvers, valves, screens or other coverings or devices, provided that they permit the automatic entry and exit of floodwaters.