[Ord. No. 5814 §1(14.1), 4-27-2004]
The "R-1" Large Lot Single-Family Dwelling District (hereinafter known in this Article as the "R-1" District) is the most restrictive form of residential land use in the City of Clayton allowing for only single-family dwellings and intended to maintain high standards for quality residential living. This district also allows for non-residential land uses, which provide services to the residential district on a conditional use permit basis.
[Ord. No. 5814 §1(14.2), 4-27-2004]
The uses permitted by right and by conditional use permit are listed in the Table of Permitted Uses found at the end of this Article. If a "P" (permitted by right) or a "C" (permitted by conditional use permit) is not indicated for a use in this table or a use is not included on the table, it is prohibited.
[Ord. No. 5814 §1(14.3), 4-27-2004]
The maximum building height in the "R-1" District is two (2) stories or forty (40) feet above grade, whichever is less. Partial stories under sloping roofs shall be permitted provided the limit in feet is not exceeded. Accessory structures may not exceed twenty (20) feet in height.
[Ord. No. 5814 §1(14.5), 4-27-2004]
The minimum lot area in the "R-1" District shall be twenty thousand (20,000) square feet. Modifications may be allowed subject to Section 405.1710.
[Ord. No. 5814 §1(14.7), 4-27-2004; Ord. No. 6986, 1-27-2026]
A. 
A minimum of fifty-five percent (55%) of the required front yard setback shall be covered by greenspace. A minimum of fifty-five percent (55%) of the total lot shall be covered by greenspace. Properties located within an urban design district must comply with the requirements for the specific urban design district.
B. 
In instances where an applicant can demonstrate just cause and subject to approval of plans for the installation and maintenance of an approved hardscape mitigation feature, the Plan Commission shall have the authority to approve up to a two percent (2%) reduction in the greenspace ratio requirement; that is down to fifty-three percent (53%) in the front yard setback and down to fifty-three percent (53%) overall greenspace; unless the property is located within an urban design district, then the requirements found therein shall apply.
[Ord. No. 5814 §1(14.8), 4-27-2004]
A. 
The following are the setback requirements for a principal building located in an "R-1" District and modifications to those requirements when certain conditions exist.
1. 
Front yard setbacks. The required setback in an "R-1" District is measured by calculating twenty-five percent (25%) of the depth of the lot measured from the front to the rear property line. The calculated setback must be a minimum of forty (40) feet from the front building facade to the front property line. The front yard setback is not required to exceed a maximum of one hundred (100) feet, although these regulations do not preclude a deeper than maximum setback at the discretion of the property owner. Modifications to the required front yard setback are permitted under the following conditions:
a. 
Where fifty percent (50%) or more of the frontage along any block face is improved with buildings that have observed a front yard line with a variation in depth of not more than ten (10) feet, the average of such front yard lines shall be the minimum setback observed in such a block face in lieu of the required front yard setback. For example, when calculating the average setback for a block face with ten (10) homes, where nine (9) homes have setbacks ranging from twenty-five (25) feet to thirty-five (35) feet and the remaining home has a forty (40) foot setback, the home with the forty (40) foot setback is not included in the calculation for the average. No front yard shall be required to exceed the maximum of one hundred (100) feet.
b. 
Where lots have double frontages or are corner lots, the required front yard setback provisions shall be provided on all streets.
c. 
If at or below the first (1st) floor level of the principal structure, an open, uncovered porch may project into the required front yard setback a distance of up to ten (10) feet or an open, covered porch or paved terrace may project into a required front yard a distance of up to five (5) feet and associated roof eaves may project up to an additional three (3) feet.
d. 
Front yard masonry garden walls, planting boxes, retaining walls, plantings or ornamental or decorative fences may be erected as part of new construction, up to four (4) feet above the grade level in the front yard, provided such structure is an integral part of the architectural feature of the principal structure, is in compliance with sight distance standards and is approved by the Architectural Review Board. Additionally, for properties located on a corner lot, no such plantings, masonry garden walls, planting boxes, retaining walls or ornamental or decorative fences shall be maintained higher than three and one-half (3½) feet above the established street grades within twenty (20) feet of any street intersection to comply with sight distance standards.
e. 
Roof eaves may project up to three (3) feet into the required front yard setback.
f. 
Windowsills, bay windows, belt courses and similar architectural features, as well as rain leaders and chimneys, may project up to two (2) feet into the required front yard setback.
g. 
Balconies may project up to five (5) feet into the required front yard setback.
h. 
Any accessory building that is not a part of the principal structure shall be located not less than sixty (60) feet from the front lot line.
i. 
Lots in excess of fifteen thousand (15,000) square feet and having one hundred (100) lineal feet of frontage or more may install two (2) drive approaches to accommodate a turnaround, with the written approval from the Director of Public Works and subject to Architectural Review Board approval (all other lots shall be limited to one (1) drive approach).
j. 
Basements and parking facilities that are completely underground may encroach into the front yard setback but may not transverse the property line.
2. 
Rear yard setbacks. The required setback in an "R-1" District is measured by calculating twenty-five percent (25%) of the depth of the lot measured from the front to the rear property line. The calculated setback must be a minimum of forty (40) feet from the furthest rear wall of the principal structure to the rear property line. The rear yard setback is not required to exceed a maximum of seventy (70) feet, although these regulations do not preclude a deeper than maximum setback at the discretion of the property owner. Modifications to the required rear yard setback are permitted under the following conditions:
a. 
Open, uncovered porches, patios and above ground decks may project up to twelve (12) feet into a required rear yard, provided that the floor level is at or below the level of the first (1st) floor of the principal structure. Balconies at any height may project into the required rear yard a maximum distance of five (5) feet.
b. 
Where a corner lot exists and thereby two (2) front yards, the property line opposite to the front yard line with the greater street frontage shall be considered the side yard and the property line opposite to the front yard line with the lesser street frontage shall be considered the rear yard.
c. 
One (1) or more accessory buildings may be located in the rear yard. However, the combined footprint may not occupy more than thirty-five percent (35%) of the required rear yard area and no accessory building shall be closer than ten (10) feet to the principal building nor closer than five (5) feet to any rear property line. Additionally, accessory buildings may not exceed twenty (20) feet in height.
d. 
Outside stairways, deck stairs, tower balconies and fire escapes may project up to four (4) feet into the required rear yard setback.
e. 
Roof eaves may project up to three (3) feet into the required rear yard setback.
f. 
Windowsills, bay windows, belt courses and similar architectural features, as well as rain leaders and chimneys, may project up to two (2) feet into the required rear yard setback.
g. 
Basements and parking facilities that are completely underground may encroach into the rear yard setback but may not transverse the property line.
3. 
Side yard setbacks. The required setback in an "R-1" District is measured by calculating ten percent (10%) of the width of the total lot. The calculated setback must be a minimum of twelve (12) feet up to a maximum of twenty-five (25) feet, although these regulations do not preclude a wider than maximum setback at the discretion of the property owner. Modifications to the required side yard setback are permitted under the following conditions:
a. 
Where a lot of record at the time of the effective date of this Chapter is less than fifty (50) feet in width, the required side yard may be reduced to less than the required ten percent (10%) of the width of the lot, provided however, that no side yard shall be less than five (5) feet from the structure to the side property line.
b. 
On a corner lot, the side yard facing the street shall be set back in conformance with the required front yard on that street; provided however, that the buildable width of such lot shall not be reduced to less than thirty-five (35) feet.
c. 
No accessory building shall be closer than ten (10) feet to the principal building nor closer than five (5) feet to any side property line.
d. 
An unenclosed porte-cochere or canopy may project into a required side yard but may not encroach further than five (5) feet from the side property line.
e. 
Outside stairways, tower balconies or fire escapes may project up to four (4) feet into the required side yard setback.
f. 
Roof eaves may project up to three (3) feet into the required side yard setback.
g. 
Windowsills, bay windows, balconies, belt courses and similar architectural features, as well as rain leaders and chimneys, may project up to two (2) feet into the required side yard setback.
h. 
Basements and parking facilities that are completely underground may encroach into the side yard setback but may not transverse the property line.
[Ord. No. 5814 §1(14.11), 4-27-2004]
No existing lot of record within the "R-1" District shall be resubdivided unless the resubdivided lots conform to the area and frontage requirements of this zoning district and in addition are consistent with the lots located in the immediate neighborhood with regard to size, frontage and arrangement so as to provide an orderly pattern of development. No flag lot(s) shall be created as a result of any resubdivision.
[Ord. No. 5814 §1(14.12), 4-27-2004]
Any development proposed within the "R-1" Zoning District shall be reviewed for compliance with other plans and/or regulations of the City of Clayton. Compliance with other plans and/or regulations shall include, but not be limited to, the master plan, overlay district regulations, urban design district regulations, any other land use plan or relevant standards and guidelines to the specific site which have been accepted or adopted by the Board of Aldermen.
[Ord. No. 5814 § 1(14.13), 4-27-2004; Ord. No. 6010 § 3, 1-22-2008; Ord. No. 6067 § 2, 4-14-2009; Ord. No. 6191 § 3, 2-28-2012; Ord. No. 6802, 1-24-2023]
PERMITTED USES FOR THE "R-1" ZONING DISTRICT
"R-1"
Accessory buildings and uses customarily incidental to permitted uses not involving the conduct of business, including a private garage.
P
Accessory dwelling units (as regulated and defined in Article II and III respectively).
C
Amateur radio, home antennas and associated equipment (subject to Article XXVI).
P
Group homes for the physically and/or mentally handicap, provided that 8 or fewer unrelated persons may reside therein and further provided that no more than 2 additional persons acting as house parents or guardians, who need not be related to one another or any of the residents, may also reside therein, and provided further, however, that the maximum occupancy limitations for the structure as established by the Property Maintenance Code and Fire Code, if applicable, adopted by the City and as amended and in force at the time of approval of occupancy, may not be exceeded.
No group care home shall be permitted within 500 feet from any existing group care home
P
Home occupations (as regulated and defined in Article II and III respectively).
P
Parks and playgrounds.
P
Places of religious worship, but no new or enlarged place of religious worship shall be located upon a lot or tract containing less than 1 acre. Places of religious worship may be erected to a height not exceeding 75 feet if the building is set back from each yard line at least 1 foot for each foot of additional building height above the height limit otherwise permitted in the district in which the building is built.
P
Residential--single-family dwelling unit 20,000 square feet minimum lot area per dwelling unit.
P
Child day care home.
C
Church spires, belfries, monuments, ornamental towers and spires and chimneys exceeding the maximum height in the zoning district may be erected to such height authorized by the Board of Aldermen of the City by conditional use permit or general ordinance.
C
Facilities (subject to Article XXVII)
P
Properties fronting the south side of Forsyth Boulevard from University Lane on the west to the east City limits: this area presents special use and aesthetic characteristics which require careful balance and special attention. The patent residential character of the structures in this area is a predominant feature which must be preserved for harmony with internal and contiguous residential uses, while the area's proximity to Washington University suggests reasonable allowance for ancillary education-related activities. Therefore, in this part of the "R-1" District only, education and institutional uses may be conditionally permitted in existing residential structures provided such uses are limited to guest lodging, offices, conference and meeting facilities and similar ancillary activities if, in addition to the other standards for conditional uses provided in this Chapter, all parking for such a proposed use is provided outside the "R-1" District and:
C
1.
The residential appearance of the structure and yard areas is preserved;
2.
Hours of operation are limited to times which will not interfere with the peaceful enjoyment of residential properties in and adjacent to the area; and
3.
The use will not result in excess traffic or light, smoke, noise or other emissions in compatible with residential neighborhoods in the City of Clayton.
Properties fronting the south side of Forsyth Boulevard from University Lane on the west to the east City limits: private schools, nursery, pre-kindergarten, kindergarten, play and special schools. No additions or structural alterations shall be made on the exterior of the building, except those determined to be minor, compatible and desirable.
C
Solar energy systems, building-mounted (subject to the provisions of Article XXVIII)
P
Solar energy systems, ground-mounted (subject to the provisions of Article XXVIII)
C
Wind energy systems, building-mounted (subject to the provisions of Article XXVIII)
C
P = Permitted by right
C = Permitted with conditional use permit
Note: Uses not appearing in this table are prohibited.