(1)   One single family detached dwelling per lot, designed for and occupied exclusively as a residence by one family, either owner or renter occupied.

      (2)   Publicly owned facility or land.

      (3)   Non-commercial horticulture or agriculture.

      (1)   Accessory use in compliance with the provisions in Article XV.

      (2)   Customary home occupation established under the provisions in Article XV.

      (4)   Lots containing two occupied dwellings:

         (a)   Documentation that since August 1, 1977, both dwellings have been continually occupied by a family member or under a long-term rental agreement;

         (b)   If one or both buildings remain unoccupied or not rented for a period of more than one (1) year, then the right to occupy one of the two buildings shall be terminated; and,

         (c)   If rented, a current rental agreement must be on file with the Town.

      (5)   Electrical and water meters:

         (a)   Only one electrical and/or water meter shall be allowed per residentially zoned lot.

         (b)   An owner shall be permitted to maintain additional meters if the additional meters were lawfully installed on a legally authorized dwelling for which a Certificate of Occupancy was duly issued at the time of the original ratification of the Zoning Ordinance in 1977; provided, such additional meter's use has not been discontinued as evidenced by a lack of use for a period of at least one (1) year. In the event any additional meter is removed, no additional electrical and/or water meter shall be reinstalled in place thereof.

      (6)   Attached additions that do not share heated space with the principal dwelling provided

         (a)   No kitchen facilities are allowed, and

         (b)   Deed restrictions are placed on the property prohibiting rental as a separate dwelling, and

         (c)   Any attached addition with an established connection to the principal building, shall be located under one roof and retain a permanent floor constructed above grade. The length to width ratio of the proposed connection may not exceed a two to one (2:1) dimension ratio, with a minimum width of four (4) feet, a maximum length of twenty (20) feet, and shall be visually and architecturally integrated with the existing principal building; said structures, as conditional uses, being reviewed and aesthetically approved by the Design Review Board. (9/17/2013)

      (1)   Definition and approval.

         (a)   A use permitted in a zoning district that possesses characteristics that require certain controls in order to ensure compatibility with other uses in the district within which they are proposed for location and therefore shall be approved by the Board of Zoning Appeals.

         (b)   In addition to requiring the approval of the Board of Zoning Appeals, special exceptions in the RS-Single Family District are subject to specific conditions that are enumerated by type of use.

      (2)   Historic structure used as accessory dwelling unit. As an incentive to preserve historic structures and avoid their demolition, a second dwelling may be constructed on the same lot as an historic structure, and the historic structure may be used as an accessory dwelling, when all of the following conditions are met:

         (a)   Prior use shall have been used as a dwelling; and

         (b)   The size of the historic structure is less than twelve hundred (1200) square feet of heated space at the time of its designation as historic and is listed as an historic property as described in Section 21-94 Historic Property Designation Criteria; provided, however, that a structure reduced to less than 1200 square feet of heated space after its designation as historic may qualify for special exception approval for an additional dwelling on the same lot, but only if the Design Review Board review determines and specifies in findings, that: (5-15-07)

            a.   Special circumstances justify such reduction in square feet based on the criteria listed in Section 21-94D. (1-8); and (5-15-07)

            b.   The portions removed from the historic property were added less than fifty (50) years ago and/or obscured an earlier feature of the historic house which contributed substantially to the most important elements of its historic character, definition and integrity. Examples of the latter instance include the removal of an enclosure of a porch when the open porch had been characteristic of a particular type of Island structure, or removal of an addition which covered a distinctive feature of the structure that is shared by neighboring structures. (5-15-07)

            These provisions shall supersede any inconsistent provisions contained in other portions of Chapter 21 relating to the use of historic structures as accessory dwellings, including but not limited to Section 21-140. (5-15-07)

         (c)   In the event the historic structure does not meet current FEMA elevation requirements, the Design Review Board finds that bringing it into compliance would significantly impair the historic and architectural character of the structure; and

         (d)   In the event the historic structure meets current FEMA elevations requirements, the Design Review Board finds that there is no feasible design solution for an addition to the historic structure that would not significantly impair the historic and architectural character of the structure; and

         (e)   No separate utility service meters shall be permitted; and

         (f)   The Design Review Board must find that the height, scale, mass and placement of the second structure are appropriate to and compatible with the lot on which it is sited, the character of the historic structure and surrounding neighborhood. When necessary to achieve such appropriateness and compatibility, the Design Review Board may impose stricter limits on height, setback, size and coverage than those of the zoning standards; and

         (g)   Permission to build a second structure and to use the historic structure as an accessory dwelling is approved as a special exception by the Board of Zoning Appeals; and

         (h)   The following conditions as covenants running with the property shall be placed on the real estate title to the property by the owner of the lot by recording deed restrictions for the benefit of the Town of Sullivan's Island on the owner(s) title and recording the same in the RMC office for Charleston County before a building permit is issued:

            (i)   The lot shall remain in single ownership; more specifically, regardless of the type of ownership every owner, member, partner, shareholder, or unit owner, must have the same percentage of ownership in the historic structure as in any additional structure(s); and

            (ii)   Every owner, member, partner, shareholder or unit owner must have the same amount of control over the use of the historic structure as over any additional structure(s); and

         (i)   If the historic structure used as an accessory dwelling is damaged or destroyed, by natural disaster, civil strife or uncontrollable accident, by more than fifty percent (50%) of its assessed value based on the most recent property assessment, the structure may be repaired in accordance with its preexisting footprint, square footage, setbacks, and lot coverage. The Zoning Administrator shall rely on all credible information provided by the owner and/or available from the Town, to establish the damaged or destroyed structure's pre-existing condition and lot location. A Certificate of Zoning Compliance and a Building Permit shall be obtained within twelve (12) months of the date of occurrence of such damage, and once issued, construction shall be diligently pursued and completed within two (2) years from the date of the occurrence of such damage. If FEMA regulations require the structure's foundation to be elevated over fifty percent (50%) above its original elevation, the Design Review Board shall determine whether or not the reconstruction shall be required to meet the current Zoning Ordinance's Setback requirements.

(Ord. 2018-07, passed 11-20-2018) (2-20-24)

         (j)   The historic structure used as an accessory dwelling may be used as a long-term rental, but only so long as the principal structure is occupied by an owner of the property as primary residence and a current business license is held on the same property. Primary residence is defined as a dwelling where the owner or owners reside on a permanent basis and are assessed at the four percent (4%) assessment rate on their ad valorem property tax.

      (3)   Religious institution:

         (a)   Limited to one building per lot;

         (b)   Housed in a permanent building;

         (c)   Located on a lot not less than one-half (1/2) acre in area;

         (d)   Provides off-street location for picking-up and dropping-off adults and children;

         (e)   Provides adequate off-street parking, in accordance with Article XVI; and,

         (f)   Meets the Setback and lot coverage standards of the RS District.

      (4)   Public utility substation:

         (a)   Shall be fenced or enclosed to provide adequate safety with a plan approved by the Design Review Board;

         (b)   Does not provide office, operational functions or storage of vehicles or equipment beyond the required utility equipment to provide service at that location;

         (c)   Meets the Setback and lot coverage standards of the RS District.

      (5)   Conservation Easement Uses as defined in Section 21-203 Definitions.

         (a)   Purpose. It is the purpose of this section to recognize that all properties on Sullivan's Island are part of a dynamic and ever-changing barrier island environment, vulnerable to erosion and catastrophic flooding events. Whereas all Island properties in close proximity to marshes, beaches and waterways are predisposed to erosion, loss of critical dune vegetation and structural damage during large storm events, the Town recognizes a need to develop innovative methods to incentivize the protection of open space, preserve view-shed corridors, and reduce the intensity of residential land uses. (11-17-15)

         (b)   Applicability. As an incentive to preserving environmentally sensitive properties zoned for residential purposes (RS District), property owners (grantor) may establish certain recreational uses and structures as part of a permanent conservation easement. These non-residential uses must include retaining or protecting natural or open-space values of real property, assuring its availability for noncommercial agricultural, forestall, recreational, or open-space use, protecting natural resources, maintaining or enhancing air or water quality, or preserving the historical, architectural or archeological aspects of real property. The Board of Zoning Appeals may authorize a conservation easement structure or use upon a finding that establishment of the use or structure will not be of a substantial detriment to an adjacent property or to the public good, and the granting of the use or structure will not harm the character of the district. (11-17-15)

         (c)   General Conditions.

            i.   Prior to issuance of a building permit the property owner must remove any previously constructed structures, driveways, recreational structures (pools, courts, sheds, etc.), pervious or impervious surfaces, and utilities associated with any previous residential or commercial development. (11-17-15)

            ii.   Use of the property for commercial or rental activity is expressly prohibited. (11-17-15)

            iii.   The use of the property shall be limited to owners and guests, not to exceed twenty-four (24) individuals at any given time. (11-17-15)

         (d)   Structures.

            i.   Size. One open-air structure (gazebo, cabana, pergola, arbor, or other open-air structure) not exceeding in square footage, five (5) percent of the parcel's total upland area, or two hundred fifty (250) square feet, whichever is less. A potential increase of two (2) percent will be allowed to the structure's square footage, with a 450 square foot maximum, if an existing residential structure has been removed from the parcel. (11-17-15)

            ii.   Height. Structure may not exceed a maximum height of ten (10) feet from the natural grade as measured from the center point of the proposed structure to the highest point of the roof. Height may be extended to thirteen (13) feet where the majority pitch of the structure's roof is 4/12 or more. An increase in height may be allowed if the roof’s lowest horizontal structural member must be constructed above the Base Flood Elevation (BFE), however, under no circumstances may roof height exceed 3 feet over BFE. (11-17-15)

            iii.   Storage. The structure may contain no more than thirty (30) percent of the total allowed square footage as enclosed area designated for storage space. Enclosed area may include one shower stall and must be constructed with breakaway walls and designed in accordance with FEMA National Flood Insurance Program (NFIP) regulations and the Town of Sullivan's Island Flood Prevention Ordinance. (11-17-15)

            iv.   No rooftop seating or use will be permitted. (11-17-15)

            v.   Structure may not contain sewer facilities or portable sewage collection or disposal devices. Following the removal of any existing sewer facilities, all the requirements of Town Code of Ordinance Chapters 50 and 51 shall be met (Water and Sewer Utility Regulations.) (11-17-15)

            vi.   Lighting. There shall be no exterior site or structural lighting. Interior lighting shall be designed and arranged to prevent glare on adjoining properties, adjacent Recreation and Conservation Area Districts, or any other area of the beach or marsh. (11-17-15)

            vii.   Building setback. Fifteen (15) foot setbacks are required from all property lines and must meet the approval of the South Carolina Department of Health and Environmental Control and Ocean and Coastal Resource Management (DHEC-OCRM) agencies prior to submitting an application for Special Exception consideration. The Board of Zoning Appeals may adjust the setback requirement in instances where severe erosion, historic structures, natural topography, or trees and vegetation poses an unnecessary hardship for meeting the required fifteen (15) foot setback. (11-17-15)

         (e)   Parking.

            i.   A maximum of two vehicles will be permitted on the subject property. (11-17-15)

            ii.   All parking surfaces must remain in its natural state or turf grass. No additional impervious or engineered surfaces will be permitted. (11-17-15)

            iii.   No temporary outdoor storage of vehicles, recreational vehicles, boats, camping facilities, temporary event structures, machinery, or beach equipment shall be permitted except during the daytime use of the property. (11-17-15)

         (f)   Open Storage. No permanent outdoor storage permitted. Outdoor storage is defined as the keeping within an unroofed and unenclosed area any foods, material, merchandise, or vehicles. (11-17-15)

         (g)   Neighborhood Compatibility. The Design Review Board must review all proposed conservation easement structures to ensure design compatibility with the surrounding neighborhood and ensure an environmentally sensitive, low scale design, which maximizes public view corridors. No structure height, square footage, or massing increases will be permitted by the Design Review Board. (11-17-15)

         (h)   Legal Instrument for Permanent Protection. The instrument of permanent protection shall be a permanent conservation easement recorded by the Charleston County Register of Mesne Conveyance Office (RMC), concurrent with the issuance of a Town of Sullivan's Island Building Permit and land disturbance permit: (11-17-15)

            i.   A land trust or similar conservation-oriented non-profit organization (grantee) with legal authority to accept such easements. The organization shall be bona fide and in perpetual existence and the conveyance instruments shall contain an appropriate provision for retransfer in the event the organization becomes unable to carry out its functions, and; (11-17-15)

            ii.   The Town shall receive a copy of the Annual Conservation Easement Inspection Report, and; (11-17-15)

            iii.   The Town of Sullivan's Island shall reserve a third-party right of enforcement in the conservation easement agreement. (11-17-15)

      (1)   Residences that contain less than one thousand (1,000) square feet of enclosed living area;

      (2)   Erosion control structures.

      (3)   Guest bedroom or dwelling unit for a person or persons not meeting the Zoning Ordinance's definition of "family" or not lawfully occupied in accordance with (6) below.

      (4)   Mobile homes or manufactured homes.

      (5)   Non-commercial horticulture or agriculture that includes poultry, bovine or swine or any other type of non-traditional animal or reptile.

      (6)   Vacation Rentals other than those permitted in accordance with ARTICLE XIII.

(Ord. 2023-07, passed 2-20-2024)

      (5)   Principal building front facade.

         (a)   Purpose.

            a.   The overall width and depth of a Principal Building has a substantial impact on the Principal Building’s mass and scale and how well the Principal Building blends with existing development of the island.

         (b)   Definitions.

            a.   Primary Front Facade. The largest front facing surface of the Principal Building that is parallel or nearly parallel to the front yard street frontage and is considered to be the front of the structure.

         (c)   Design standards for primary front facade.

            a.   The width of a Principal Building’s Primary Front Facade shall not exceed the lesser of fifty (50) feet or two-thirds (2/3) of the lot’s buildable width (width of lot at the building line less that portion required to meet the side yard Setbacks). All other front facing facades shall be set back at least eight (8) feet from the Principal Building’s Primary Front Facade.

            b.   A Principal Building having a porch or porches with a depth of eight (8) feet extending across forty percent (40%) of the Principal Building’s Primary Front Facade 1st floor shall be exempt from meeting the requirement of (a) above.

      (1)   Lots equal to or greater than one hundred five (105) feet wide as measured at the required Front Yard Setback Line:

         (a)   The combined Side Yard Setback for both sides shall be equal to a minimum of forty (40) feet with a minimum average setback for any one side of fifteen (15) feet, with the minimum distance from the property line of ten (10) feet on one side and twenty (20) feet on the other.

         (b)   Encroachments within fifteen (15) feet of the side property line are not permitted within twenty (20) feet of the front facade of the home.

      (2)   Lots less than one hundred five (105) feet wide as measured at the required Front Yard Setback Line:

         (a)   The required Side Yard Setback may be reduced by one-third (1/3) foot for each foot by which the lot width is less than one hundred five (105) feet rounded up or down to the nearest whole foot; provided, however, the Side Yard Setback shall never be less than ten (10) feet.

         (b)   Encroachments within fifteen (15) feet of the side property line are not permitted within twenty (20) feet of the front facade of the home, unless the lot width is less than seventy-five (75) feet wide.

      (3)   Secondary side yard setback requirements:

         (a)   Ground level and first floor elements shall not exceed thirty-eight (38) feet in length along the side facade without an articulation.

         (b)   Second floor elements shall not exceed thirty-two (32) feet in length along the side facade without an articulation. This application shall not apply to second floor elements whose knee wall is less than six (6) feet high.

         (c)   No side facade shall exceed sixteen (16) feet in length when located within fifteen (15) feet of the side property line, and a total of no more thirty-two (32) linear feet of side facade may be located within fifteen (15) feet of the side property lines on the lot.

         (d)   Articulations shall be a minimum of sixteen (16) inches (1.25 feet) in depth and a minimum of nine (9) feet in length; the length may be reduced by a foot for every sixteen (16) inches of increased depth, but a minimum of a 2:1 length to depth ratio must be maintained.

         (e)   A porch or deck with a minimum depth of six (6) feet, meeting the 2:1 length to depth ratio, may be substituted for the articulation requirement.

         (f)   Second floor elements shall be subject to an additional five- (5-) foot setback on each side, with a minimum average setback on one side of twenty (20) feet and a minimum distance from the property line of at least fifteen (15) feet, and minimum average setback on the other side of at least thirty (30) feet with a minimum distance to the property line of at least twenty (20) feet. This application shall not apply to second floor elements whose knee wall is less than six (6) feet high.

      (4)   Accessory structures Side Yard Setbacks.

         (a)   See Article XV for Setbacks required for accessory structures.

      (5)   Design Review Board. The Design Review Board may grant up to a twenty-five percent (25%) modification to any of these zoning standards, except that no portion of the Principal Building or attached porches or decks may be closer than ten (10) feet to a side property line, if the modification or other modifications achieve greater Neighborhood Compatibility as described in Article XII.

(Ord. 2024-04, passed 6-18-2024)

         (a)   accessory structures not readily useable as living space;

         (b)   exterior porches and decks; and,

         (c)   exterior stairs.

      (1)   Lot Area equal, to or greater than fifteen thousand (15,000) square feet:

         (a)   Principal Building Coverage Area shall be no greater than fifteen percent (15%) of the Lot Area.

         (b)   Example (18,000 sf Lot Area): 18,000 sf lot x 15% = 2700 sf Principal Building Coverage Area permitted (15% of Lot Area).

      (2)   Lot Area less than fifteen thousand (15,000) square feet:

         (a)   Principal Building Coverage Area shall be no greater than fifteen percent (15%) times Lot Area plus fifteen thousand (15,000) square feet minus the Lot Area times five percent (5%).

         (b)   Example (12,000 sf Lot Area): (15% x 12,000 sf) + [(15,000 sf - 12,000 sf) x 5%] = 1950 sf Principal Building Coverage Area permitted (16.3% of Lot Area).

      (3)   Examples. 1/2 acre Lot 21,780 sf= 3267 sf Coverage (15%).

         (a)   1/3 acre Lot 14,505 sf- 2176 sf Coverage (15%).

         (b)   1-4 acre Lot 10,890 sf - 1634 sf Coverage (20%).

         (c)   Lot 5,000 sf= 1250 sf Coverage (25%).

      (1)   The Design Review Board may increase by no more than twenty percent (20%) the maximum permitted Principal Building Coverage Area if this or other modifications achieve greater Neighborhood Compatibility as described in ARTICLE XII. (5-15-07) (2-20-24)

(Ord. 2023-07, passed 2-20-2024)

         (a)   interior space not readily useable as living space (attic used only for storage or parking area beneath dwelling);

         (b)   structures that are not used as living space;

         (c)   exterior porches and decks; and,

         (d)   exterior stairs.

      (1)   Lot Area of five thousand (5,000) square feet or less: Principal Building Square Footage limited to twenty four hundred (2400) square feet.

      (2)   Lot Area exceeding five thousand (5,000) square feet: maximum Principal Building Square Footage of twenty four hundred (2400) square feet may be increased 10 sf for every additional 100 square feet of Lot Area.

      (3)   Equation: [(Lot Area - 5000 sf) / 100 sf] x (10) + 2400 = Principal Building Square Footage.

Examples:

         (a)   1/2 acre Lot 21,780 sf= 4078 Principal Building Square Footage.

         (b)   1/3 acre Lot 14,505 sf= 3351 Principal Building Square Footage.

         (c)   1/4 acre Lot 10890 sf= 2989 Principal Building Square Footage.

         (d)   Lot 5,000 sf= 2400 Principal Building Square Footage.

      (4)   The maximum permitted Principal Building Square Footage is fifty six hundred (5600) square feet for any newly constructed single-family home. Existing buildings shall be exempt from the 5600 square foot requirement and able to utilize their total principal building square footage for single-family use. (12-17-13)

      (1)   The Design Review Board may increase by no more than fifteen percent (15%) and not to exceed five hundred (500) square feet added to the maximum permitted Principal Building Square Footage if this or other modifications achieve greater Neighborhood Compatibility as described in ARTICLE XII except:

         (i)   In cases of the special exception, Section 21-20C.(2), allowing a second residential structure on a lot with the historic structure used as an accessory dwelling unit, wherein the Design Review Board may permit increases in the Principal Building Square Footage by no more than twenty-five percent (25%), or

         (ii)   In cases where the subject property has been designated historic, per Section 21-94, wherein the Design Review Board may permit increases in the Principal Building Square Footage by no more than twenty percent (20%). (5-15-07) (2-20-24)

      (2)   However, in no case shall any Principal Building Square Footage exceed 5,600 square feet or, when applicable, the principal square footage permitted in Sec. 21-27B.(4). (5-15-07) (12-17-13)

   D.   Notwithstanding any of the requirements in Sec. Sec. 21-27A.-C. above, single family residential structures in the CCOD 1 District may be permitted only if the principal building coverage area shall not exceed 80% of the maximum principal building square footage otherwise permitted in Sec. Sec. 21-27A.-C. The Design Review Board shall not have the authority to increase the principal building square footage as set forth in Sec. 21-27C. for single family residential structures on CCOD 1 or 2 Overlay District lots; provided, however, the Design Review Board may exercise the discretion described in Sec. 21-49. (6/19/07) (3/20/12)

(Ord. 2023-07, passed 2-20-2024)

      (1)   The bottom elevation of the Principal Building's lowest horizontal structural member shall be no more than eight (8) feet above finished grade.

      (2)   The finished floor shall be no more than nine (9) feet four (4) inches above finished grade.

      (3)   If the base flood elevation (BFE) conflicts with the maximum height limitations noted above in Sections 21-31B.(1)-(2), the lowest horizontal structural member shall be no higher than the design flood elevation (DFE) with a finished floor elevation (FFE) no higher than two (2) feet above DFE elevation.

      (4)   The standards outlined in B.(1)-(3) do not apply to designated historic buildings. Designated historic building must comply with the standards set forth in Section 21-44.

(Ord. 2020-17, passed 11-17-2020) (2-20-24)

(Ord. 2023-07, passed 2-20-2024)

      (1)   Exempt the Principal Building's pre-existing nonconforming Setbacks in order to permit additions in keeping with the Principal Building's historic character; and,

      (2)   Permit the Principal Building to be used as accessory dwelling unit only specified in previous section 21-20C., occupied by persons meeting the Zoning Ordinance's definition of "family." (2-20-24)

(Ord. 2023-07, passed 2-20-2024)

      (1)   Height: To minimize the height of elevating historic structures, the finished floor elevation (FFE) shall exceed no more than three (3) feet above finished grade.

      (2)   Composition and Scale: To maintain an historic building's visual character and design compatibility with the surrounding neighborhood, an elevation design plan shall be submitted to illustrate the composition and scale of the building's principal architectural features are being maintained and will remain proportional to the elevated foundation.

      (3)   Perspective and Orientation: Any proposed elevation or relocation should maintain the building's historic perspective from the principal right-of-way. All historic architectural elements should be maintained after elevation or relocation.

      (4)   Scale Minimization and Architectural Screening: Appropriate measures should be introduced into the site design to reduce or eliminate negative visual effects from the elevation of a historic structure. These elements include fencing, landscaping (foundation plantings), stair configuration and any other site considerations noted by the Design Review Board.

(Ord. 2017-04, passed 8-15-2017; Ord. 2023-07, passed 2-20-2024)