§ 151-18  Standards for Construction.
   In all Special Flood Hazard Areas the following standards are required:
   (A)   Anchoring.
      (1)   All new construction and substantial improvements shall be anchored to prevent flotation, collapse or lateral movement of the structure resulting from hydrodynamic and hydrostatic loads, including the effects of buoyancy; and
      (2)   All manufactured homes shall meet the anchoring standards of § 151-22(B).
   (B)   Construction materials and methods.
      (1)   All new construction and substantial improvements shall be constructed with materials and utility equipment resistant to flood damage;
      (2)   All new construction and substantial improvements shall be constructed using methods and practices that minimize flood damage;
      (3)   All new construction and substantial improvements and other proposed new development shall be constructed with electrical, heating, ventilation, plumbing and air conditioning equipment and other services facilities that are designed and /or located so as to prevent water from entering or accumulating within the components during conditions of flooding; and
      (4)   Within Zones AH or AO, adequate drainage paths shall be constructed around structures on slopes to guide floodwaters around and away from proposed structures.
   (C)   Elevation and floodproofing.
      (1)   Residential construction.
         (a)   Residential construction, new or substantial improvement, shall have the lowest floor, including basement, elevated to or above the RFE:
            1.   In an AO Zone, the Base Flood Elevation is determined from the FIRM panel, or elevated at least two feet above the highest adjacent grade if unspecified.
            2.   In an A Zone where a BFE has not been determined, elevated to or above the RFE.
            3.   In Zones AE and AH, the BFE is determined from the FIS and/or FIRM.
            4.   A garage attached to a residential structure, constructed with the garage floor slab below the RFE, must be designed to allow for the automatic entry and exit of flood waters and must be used solely for parking, access and/or storage. See § 151-18(C)(3).
         (b)   Upon completion of the structure, the elevation of the lowest floor including basement shall be certified by a registered professional engineer or surveyor, and verified by the community's building inspector to be properly elevated. Such certification and verification shall be provided to the FPA.
      (2)   Non-residential construction.  Nonresidential construction, new or substantial improvement, shall have the lowest floor either elevated to conform with § 151-18(C)(1), or together with attendant utility and sanitary facilities:
         (a)   Be floodproofed below the elevation recommended under § 151-18(C)(1)  so that the structure is watertight with walls substantially impermeable to the passage of water; and
         (b)   Have structural components capable of resisting hydrostatic and hydrodynamic loads and effects of buoyancy.
         (c)   Upon completion of the structure, the elevation of the lowest floor including basement shall be certified by a registered professional engineer or surveyor that the standards of this section are satisfied. Such certification shall be provided to the FPA.
      (3)   Flood openings.  All new construction and substantial improvement with fully enclosed areas below the lowest floor (excluding basements) that are usable solely for parking of vehicles, building access or storage, and which are subject to flooding, shall be designed to automatically equalize hydrostatic flood forces on exterior walls by allowing for the entry and exit of flood water. Designs for meeting this requirement must meet or exceed the following criteria:
         (a)   For non-engineered openings:
            1.   Have a minimum of two openings, on different sides of each enclosed area, 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.
            3.   Openings may be equipped with screens, louvers, or other coverings or devices provided that they permit the automatic entry and exit of flood water; or
         (b)   For engineered openings:
            1.   Engineered openings (or covers and devices) that are specifically designed and certified by a registered engineer or architect as meeting the required performance and design requirements.
            2.   Engineered openings (or covers and devices) for which an Evaluation Report has been issued by the International Code Council (ICC) Evaluation Service, Inc. (ICC-ES), a subsidiary of the International Code Council, Inc.
      (4)   Manufactured homes.  Manufactured homes shall meet the standards in § 151-22.
      (5)   Garages and low cost accessory structures.
         (a)   Attached garages.
            1.   A garage attached to a residential structure, constructed with the garage floor slab below the RFE, must be designed to allow for the automatic entry of flood waters. See  § 151-18(C)(3).  Areas of the garage below the RFE must be constructed with flood resistant materials. See § 151-18(B).
            2.   A garage attached to a nonresidential structure must meet the above requirements or be dry floodproofed.
         (b)   Detached garages and accessory structures.
            1.   Accessory structure used solely for parking (two-car detached garages or smaller) or limited storage (small, low-cost sheds), as defined in § 151-04, may be constructed such that its floor is below the RFE, provided the structure is designed and constructed in accordance with the following requirements:
               a.   Use of the accessory structure must be limited to parking or limited storage;
               b.   The portions of the accessory structure located below the RFE must be built using flood-resistant materials;
               c.   The accessory structure must be adequately anchored to prevent flotation, collapse and lateral movement;
               d.   Any mechanical and utility equipment in the accessory structure must be elevated or floodproofed to or above the RFE;
               e.   The accessory structure must comply with floodway encroachment provisions in § 151-24; and
               f.   The accessory structure must be designed to allow for the automatic entry of flood waters in accordance with § 151-18(C)(3).
            2.   Detached garages and accessory structures not meeting the above standards must be constructed in accordance with all applicable standards in § 151-18.
            3.   Upon completion of the structure, certification by a registered professional engineer or surveyor, and verified by the community's building inspector to be properly constructed. Such certification and verification shall be provided to the FPA.
      (6)   Machinery and service equipment. All new construction, substantial improvement, and other proposed new development shall be constructed with electrical, heating, ventilation, plumbing, air conditioning equipment, and other service facilities that are designed and/or located so as to prevent water from entering or accumulating within the components during conditions of flooding.
(Ord. O2006-53, passed 8-16-06; Ord. O2021-013, passed 7-21-21)