City of Lake Saint Louis, MO Article III Measurements And Exceptions

Section 410.110 Generally.

[Ord. No. 4190, 2-1-2021]

A. The purpose of this Article is to provide uniform requirements for measuring dimensional standards and to list any exceptions to the dimensional standards in this Code.

B. For the purposes of determining compliance with dimensional standards of this Code, the following shall apply:

1. Private streets shall be treated as if they are public rights-of-way.

2. A structure or unit itself, or a structure or unit taken together with any unimproved and contiguous common elements, shall constitute the functional equivalent of a lot in the following circumstances:

a. Condominium units and buildings.

b. Townhomes and duplexes when each unit is located on an individual lot.

c. Nonresidential structures when each unit or structure is located on an individual lot.

d. Principal structures when located on a single lot containing more than one (1) principal structure.

3. Where a future right-of-way line is shown on a thoroughfare plan adopted by the City, St. Charles County, or the Missouri Department of Transportation, the future right-of-way line shall be used instead of the existing right-of-way line.

C. When calculations result in fractions, the following shall apply:

1. If the standard is expressed as a minimum requirement, then the fraction shall be rounded up to the nearest whole number.

2. If the standard is expressed as a maximum allowance, then the fraction shall be rounded down to the nearest whole number.

D. Distances specified in this Code are to be measured as the length of an imaginary straight line joining those points, unless otherwise expressly stated.

Section 410.120 Lot Standards.

[Ord. No. 4190, 2-1-2021]

A. Lot Area.

1. Lot area is the total horizontal area included within lot lines.

B. Lot Area Per Dwelling Unit.

1. Lot area per dwelling unit is the minimum lot area that is required for each dwelling unit on the property.

C. Lot Width.

1. Lot width is the horizontal distance between the side lot lines, measured at the front setback line.

Figure 410.120.C

Lot Width

2. On corner lots, lot width is measured between the side lot line and the opposite front lot line along the front setback line.

3. On lots located on a concave curve, lot width is measured between the side lot lines along a line tangent to the midpoint of the front setback line.

4. On lots located on a convex curve, lot width is measured between the side lot lines along the chord of the front setback line.

5. On lake lots, the minimum lot width is measured at both the front setback line and rear setback line.

D. Lot Width Per Dwelling Unit.

1. Lot width per dwelling unit is the minimum lot width that is required for each dwelling unit on the property.

E. Lot Depth.

1. Lot depth is the horizontal distance between the front and rear lot lines measured at right angles to the front lot line.

Figure 410.120.E

Lot Depth

2. Where the front and rear lot lines are not approximately parallel, the lot depth shall be the average of the length of the two (2) side lot lines.

Section 410.130 Setback Standards.

[Ord. No. 4190, 2-1-2021]

A. Setback.

1. A setback is the distance between a building, structure, improvement, or site feature, and any lot line.

2. Required setbacks shall be unobstructed from ground level to the sky except as specified in Table 410.130.G, Permitted Setback Projections, or as provided in this Code.

Figure 410.130.A

Setbacks

B. Setback Line.

1. A setback line is a line drawn parallel to a lot line at a distance therefrom equal to the depth of the required setback. (See Figure 410.130.A.)

C. Front Setback.

1. A front setback extends across the full width of the front of a lot, the required depth of which is measured from the front lot line. (See Figure 410.130.A.)

2. On corner lots and double-frontage lots each lot line with street frontage is considered a front lot line and therefore has a required front setback.

D. Rear Setback.

1. A rear setback extends across the full width of the rear of the lot, the required depth of which is measured from the rear lot line. (See Figure 410.130.A.)

2. On corner lots, the lot line opposite the front lot line with the least amount of frontage is the rear lot line and therefore has a required rear setback.

3. On double frontage lots and pie-shaped lots, there is no rear lot line and therefore no rear setback.

E. Side Setback.

1. A side setback extends from the front setback line to the rear setback line, the required depth of which is measured from the side lot line. (See Figure 410.130.A.)

2. Duplex and townhouse dwelling units sharing a common wall shall not be required to comply with side setback requirements except for the outside walls of the end units.

F. Building Separation.

1. Building separation is the required minimum distance between the nearest portions of any principal structures on a single lot.

G. Exceptions.

1. The features listed in Table 410.130.G, Permitted Setback Projections, shall be permitted to project into the required setbacks of the applicable zoning district. The exceptions apply to all zoning districts unless otherwise stated.

2. When a feature is not listed in Table 410.130.G, Permitted Setback Projections, the feature may not be located in a yard or project into the required setbacks unless the Community Development Director determines that the feature is reasonably comparable to a feature that is already listed.

3. Projections shall not extend or encroach into a public or private easement or right-of-way, except as permitted in Section 510.010, Obstruction on Streets and Sidewalks - Easement Encroachment - Exceptions, of the Municipal Code, nor obscure a required visual clearance area as described in Section 425.080, Visibility at Intersections.

4. The standards listed in Table 410.130.G, Permitted Setback Projections, may be waived or modified through one of the following procedures, except where an alternative procedure is specified in this Article:

a. Minor adjustment (Section 405.220).

b. Variance (Section 405.230).

c. Zoning Map amendment (Section 405.100) to planned unit development (Section 415.130).

Table 410.130.G Permitted Setback Projections
				Front				Side				Rear
Permitted Encroachment	Attached or Freestanding	Covered or Uncovered	Enclosed or Unenclosed	Permitted in Yard	Permitted in Setback	Maximum Setback Encroachment	Minimum Setback	Permitted in Yard	Permitted in Setback	Maximum Setback Encroachment	Minimum Setback	Permitted in Yard	Permitted in Setback	Maximum Setback Encroachment	Minimum Setback
Agricultural structures	Freestanding	Covered	Enclosed	Yes	No	—	—	Yes	No	—	—	Yes	No	—	—
Architectural features	Attached	—	—	Yes	Yes	2 feet	None	Yes	Yes	2 feet	None	Yes	Yes	2 feet	None
Awnings and canopies	Attached	—	—	Yes	Yes	None	None	Yes	Yes	None	None	Yes	Yes	None	None
Balconies	Attached	Covered or uncovered	Unenclosed	Yes	Yes	6 feet	None	Yes	No	—	—	Yes	No	—	—
Basketball goals	Freestanding	—	—	Yes	Yes	None	10 feet from edge of pavement or back of curb	Yes	No	—	—	Yes	No	—	—
Boat docks	Freestanding	—	—	Yes	Yes	None	None	Yes	Yes	None	None	Yes	Yes	None	None
Decks	Attached or freestanding	Uncovered	Unenclosed	No	No	—	—	Yes	Yes	1/2 of the required setback	None	Yes	Yes	1/2 of the required setback	None
Decorative fences or walls (less than 18 inches), retaining walls	Freestanding	—	—	Yes	Yes	None	None	Yes	Yes	None	None	Yes	Yes	None	None
Donation collection bins	Freestanding	—	—	Yes	No	—	—	Yes	No	—	—	Yes	No	—	—
Fences (Refer to Section 425.110, Fences.)	Freestanding	—	—	—	—	—	—	—	—	—	—	—	—	—	—
Flagpoles	Freestanding	—	—	Yes	Yes	1/2 of the required setback	None	Yes	Yes	1/2 of the required setback	None	Yes	Yes	1/2 of the required setback	None
Gasoline station canopies, multi-pump dispensers, and service islands (Refer to Section 420.090(A), Gasoline Stations.)	Attached or freestanding	—	—	—	—	—	—	—	—	—	—	—	—	—	—
Gazebos	Freestanding	Covered	Unenclosed	No	No	—	—	Yes	Yes	1/2 of the required setback	None	Yes	Yes	1/2 of the required setback	None
Mechanical equipment	Attached or freestanding	—	—	No	No	—	—	Yes	Yes	3 feet	None	Yes	Yes	1/2 of the required setback	None
Outdoor dining, outdoor display and sales	Freestanding	—	—	Yes	Yes	None	None	Yes	Yes	None	None	Yes	Yes	None	None
Parking spaces	Freestanding	—	—	Yes	Yes	None	10 feet	Yes	Yes	None	10 feet	Yes	Yes	None	10 feet
Patios and terraces	Attached or freestanding	Uncovered	Unenclosed	Yes	Yes	6 feet	None	Yes	Yes	None	None	Yes	Yes	None	None
Pergolas and arbors	Attached or freestanding	Covered	Unenclosed	No	No	—	—	Yes	Yes	1/2 of the required setback	None	Yes	Yes	1/2 of the required setback	None
Play equipment and recreational courts (outdoor)	Freestanding	—	—	No	No	—	—	Yes	Yes	1/2 of the required setback	None	Yes	Yes	1/2 of the required setback	None
Porches and porte cocheres	Attached	Covered	Unenclosed	Yes	Yes	6 feet	None	Yes	No	—	—	Yes	No	—	—
Steps, railings, and accessibility ramps	Attached or freestanding	Uncovered	Unenclosed	Yes	Yes	None	None	Yes	Yes	None	None	Yes	Yes	None	None
Swimming pools (outdoor)	Freestanding	—	—	No	No	—	—	Yes	Yes	1/2 of the required setback (pool apron)	15 feet (pool lip or edge)	Yes	Yes	1/2 of the required setback (pool apron)	15 feet (pool lip or edge)
Trash enclosures (detached houses, duplexes and townhouses)	Attached or freestanding	Uncovered	Unenclosed	Yes	No	—	—	Yes	Yes	1/2 of the required setback	None	Yes	No	—	—
Trash enclosures (multi-unit, mixed-use and nonresidential uses)	Attached or freestanding	Uncovered	Unenclosed	Yes	Yes	10 feet	None	Yes	Yes	None	10 feet	Yes	Yes	None	10 feet
Trellises	Freestanding	—	—	Yes	Yes	None	None	Yes	Yes	None	None	Yes	Yes	None	None
Vestibules	Attached	Covered	Enclosed	Yes	Yes	2 feet	None	Yes	Yes	2 feet	None	Yes	Yes	2 feet	None
Wall cladding	Attached	—	—	Yes	Yes	5 inches	None	Yes	Yes	5 inches	None	Yes	Yes	5 inches	None

Section 410.140 Other Standards.

[Ord. No. 4190, 2-1-2021]

A. Height.

1. For buildings, height is the vertical distance above finished grade at the front of the building measured to the highest point of a flat or mansard roof, or to the midpoint of the highest gable of a pitched or hipped roof. (See Figure 410.140.A.)

Figure 410.140.A

Height

2. For other structures, height is the vertical distance above finished grade of the base of the structure measured to the highest point, including the main structure and all the attachments thereto.

3. Exceptions.

a. The following structures and features shall be permitted to project beyond the maximum height requirements of the applicable zoning district:

(1) Agricultural structures.

(2) Architectural features, such as spires, belfries, parapet walls, cupolas, domes, flues and chimneys.

(3) Structures such as elevator penthouses, gas tanks, grain elevators, radio, roof-mounted mechanical equipment, cooling towers, fire towers, and smoke stacks.

(4) Structures related to utility services, such as water towers, electric power and communication transmission lines, traffic signals, and light poles.

(5) Wireless facilities and wireless support structures, in accordance with Section 420.110(A), Wireless Communications.

B. Floor Area Ratio.

1. Floor area ratio is the total gross floor area of the building or buildings on any lot divided by the total lot area.

C. Gross Floor Area.

1. Gross floor area is the sum of the gross area of every story of a building measured from the exterior limits of the faces of the structure, excluding unfinished basements, garages, porches, attics, parking structures and parking areas.

D. Lot Coverage.

1. Lot coverage is the total area of a lot occupied by buildings, structures, and impervious surfaces, expressed as a percentage of the total lot area.

E. Net Density.

1. Net density is the number of dwelling units permitted per acre of land, excluding land dedicated for street right-of-way, floodways, retention and detention basins, areas which exceed slopes of three to one (3:1), access easements, and land cut off from the main parcel by a road, railroad or major stream such that common use is hindered or that the land is unavailable for building purposes.