Richmond Municipal Code § 15.04.103.110 Determining Lot Coverage

The purpose of this article is to explain how various measurements referred to in these Regulations are to be calculated.

For all calculations, the applicant is responsible for supplying drawings illustrating the measurements that apply to a project. These drawings must be drawn to scale and of sufficient detail to allow easy verification upon inspection by the Zoning Administrator.

Whenever the Zoning and Subdivision Regulations requires consideration of distances, parking spaces, dwelling units or other aspects of development or the physical environment expressed in numerical quantities, and the result of a calculation contains a fraction of a whole number, the results will be rounded as follows:

A. General Rounding. Fractions of one-half (0.5) or greater must be rounded up to the nearest whole number, and fractions of less than one-half (0.5) must be rounded down to the nearest whole number, except as otherwise provided.

B. Exception for State Affordable Housing Density Bonus. The calculation of fractions related to permitted bonus density units for projects eligible for bonus density pursuant to Government Code Section 65915 or any successor statute shall be done as provided by state law.

A. Measurements are Shortest Distance. When measuring a required distance, such as the minimum distance between a structure and a lot line, the measurement is made at the closest or shortest distance between the two objects.

B. Distances are Measured Horizontally. When determining distances for setbacks and structure dimensions, all distances are measured along a horizontal plane from the appropriate line, edge of building, structure, storage area, parking area, or other object. These distances are not measured by following the topography or slope of the land.

C. Measurements Involving a Structure. Measurements involving a structure are made to the closest support element of the structure. Structures or portions of structures that are entirely underground are not included in measuring required distances.

D. Measurement of Vehicle Stacking or Travel Areas. Measurement of a minimum travel distance for vehicles, such as garage entrance setbacks and stacking lane distances, are measured down the center of the vehicle travel area. For example, curving driveways and travel lanes are measured along the center arc of the driveway or traffic lane.

E. Measuring a Buffer or Radius. When a specified land use is required to be located a minimum distance from another land use, the minimum distance is measured in a straight line from all points along the lot line of the subject project, in all directions.

Figure 15.04.103.040: Measuring Distances

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A. Measuring Building Height. Building height shall be defined as the distance from finished grade to the highest point of the coping of a flat roof or to the deck line of a mansard roof or to the highest point of the highest gable of a pitched or hipped roof. The height of a stepped or terraced building is the maximum height of any segment of the building along the finished grade directly below. For structures projecting over water, height will be measured from highest grade at front (landward) property line. On lots with a grade change of 10 percent or more between the front and rear property lines, building height is measured from the "grade plane" as determined in the following subsection, and height shall be measured from the measure point at the top of the building, as determined above, to the grade plane.

Figure 15.04.103.050-A(1): Measuring Building Height

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Figure 15.04.103.050-A(2): Measuring Building Height of a Terraced or Stepped Building

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1. Measuring Building Height on Sloped Lots. On lots with a grade change of 10 percent or more between the front and rear lot lines, or between the front lot line and its most distant point when there is no rear lot line, building height is measured from the adjacent natural or finished grade, whichever is lower, to the coping of a flat roof or to the deck line of a mansard roof or to the average height of the highest gable of a pitched or hipped roof.

2. Exceptions. Antennas, belfries, chimneys, cooling towers, cupolas, domes, elevator bulkheads, flagpoles, ornamental towers, penthouses, solar collectors, spires and standpipes and necessary mechanical equipment may exceed the height limits pursuant to Section 15.04.601.050 (Exceptions to Height Limits).

B. Measuring the Number of Stories in a Building. In measuring the height of a building in stories, the following measurement rules apply:

1. A balcony or mezzanine shall be counted as a full story if its floor area exceeds one-third of the total area of the nearest full floor directly below it or if it is enclosed on more than two sides.

2. A basement shall be counted as a full story if the finished surface of the floor above the basement is:

a. More than six feet above grade plane; or

b. More than 12 feet above the finished grade at any point.

Figure 15.04.103.050-B: Determining if a Basement is a Story

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3. A story may not exceed 25 feet in height from the upper surface of the floor to the ceiling above.

C. Measuring Height of Fences or Walls. The height of any fence or wall shall be determined by measuring the vertical distance from the highest finished grade within a three-foot radius of any point on the fence or wall to the highest point of any portion of the fence or wall. In the case of fences or walls between the setback line and lot line, height shall be measured from highest finished grade adjacent to the fence or wall to the top of the fence or wall.

1. Measuring Height of Fences on Retaining Walls. The height of a fence that is on top of a retaining wall is measured from the highest finished grade point within a three-foot radius of any point on such fence to the highest point of the fence on the highest side of the wall. Any fence or railing required to comply with minimum height in applicable Building Code requirements is permitted.

Figure 15.04.103.050-C: Measuring Height of Fences and Walls

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D. Measuring the Height of Decks. Deck height is the vertical distance from finished grade directly below the deck to the top of the floor of the deck.

Figure 15.04.103.050-D: Measuring Height of Decks

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(Ord. No. 30-18 N.S., § I(Exh. A), 12-18-2018)

A. Determining Grade. Grade is the location of the ground surface. For purposes of this article, the grade of a building used to determine building height shall be determined by one or more of the following:

1. Average Grade. A horizontal line approximating the ground elevation through each building on a site used for calculating the exterior volume of a building. Average grade is calculated separately for each building.

2. Existing Grade. The existing elevation of the ground at any point on a lot. Existing grade also may be referred to as natural grade.

3. Finished Grade. The lowest point of elevation of the finished surface of the ground, paving, or sidewalk within the area between the building and the lot line, or when the lot line is more than five feet from the building, between the building and a line five feet from the building.

4. Grade Plane. A reference plane representing the average of finished ground level adjoining the building at exterior walls. Where the finished ground level slopes away from the exterior walls, the reference plane shall be established by the lowest points within the area between the building and the lot line or, where the lot line is more than five feet from the building, between the building and a point five feet from the building.

Figure 15.04.103.060-B: Grade Plane

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A. Lot Width. Lot width is the horizontal distance between the side lot lines, measured at right angles to the lot depth at a point midway between the front and rear lot lines.

B. Lot Depth. Lot depth is measured along a straight line drawn from the midpoint of the front lot line to the midpoint of the rear lot line or to the most distant point on any other lot line where there is no rear lot line.

Figure 15.04.103.070: Measuring Lot Width and Depth

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The average slope of a parcel is calculated using the following formula: S = 100(I)(L)/A, where:

S = Average slope (in percent)

I = Contour interval (in feet)

L = Total length of all contour lines on the parcel (in feet)

A = Area of subject parcel (in square feet)

The floor area of a building is the sum of the gross horizontal areas of all floors of a building or other enclosed structure, measured from the outside perimeter of the exterior walls and/or the centerline of interior walls.

A. Included in Floor Area. Floor area includes, but is not limited to, all habitable space (as defined in the Building Code) that is below the roof and within the outer surface of the main walls of principal or accessory buildings, the centerlines of party walls separating such buildings or portions thereof, or lines drawn parallel to and two feet within the roof line of any building without walls. In the case of a multi-story building that has covered or enclosed stairways, stairwells, or elevator shafts, the horizontal area of such features shall be counted only once at the floor level of their greatest area of horizontal extent. The area of mezzanines and sleeping lofts shall not be counted if the space is between two floors.

B. Excluded from Floor Area. Floor area does not include the following: mechanical, electrical, and communication equipment rooms that do not exceed two percent of the building's gross floor area; bay windows or other architectural projections where the vertical distance between the lowest surface of the projection and the finished floor is 30 inches or greater; areas that qualify as usable open space; and, in non-residential buildings, areas used for off-street parking spaces or loading spaces, driveways, ramps between floors of a multi-level parking garage, and maneuvering aisles that are located below the finish grade of the property.

C. Non-Residential Uses. For non-residential uses, gross floor area includes interior walkways interior courtyards, walkways, paseos, and corridors covered by a roof or skylight. Non-residential gross floor area does not include arcades, porticoes, and similar open areas that are located at or near street level and are accessible to the general public but are not designed or used as sales, display, storage, service, or production areas.

The floor area ratio (FAR) is the ratio of the floor area, excluding the areas described below, of all principal and accessory buildings on a site to the site area. To calculate the FAR, floor area is divided by site area, and typically expressed as a decimal. For example, if the floor area of all buildings on a site totals 20,000 square feet, and the site area is 10,000 square feet, the FAR is expressed as 2.0. In single family homes and duplexes, any portion of a floor with a ceiling height greater than 12 feet is counted twice for purposes of calculating compliance with the maximum residential floor area allowed under subsection 15.04.201.030(G).

A. Excluded from Floor Area in Calculating FAR. The following are excluded from the floor area when calculating FAR.

1. Underground Areas. Floor area located below finished grade.

2. Parking. Parking areas located below finished grade or finished floor of habitable space where the vertical distance between finished grade and finished floor is five feet or less. Structured parking areas located above finished grade where the vertical distance between finished grade and the floor of the parking level is five feet or less.

3. Sideloaded or Detached Garages. Sideloaded or detached garages not exceeding 400 square feet, located to the rear of residential structures, a minimum of 40 feet away from the front lot line, and accessed by a driveway.

Figure 15.04.103.100: Determining Floor Area Ratio

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Lot coverage is the ratio of the total footprint area of all structures on a lot to the net lot area, typically expressed as a percentage. The footprints of all principal and accessory structures, including garages, carports, covered patios, and roofed porches, shall be summed in order to calculate lot coverage. The following structures shall be excluded from the calculation:

A. Unenclosed and unroofed decks, uncovered patio slabs, porches, landings, balconies, and stairways less than 18 inches in height at surface of deck (and less than six feet above grade including railings);

B. Eaves and roof overhangs projecting up to two feet from a wall;

C. Trellises and similar structures that have roofs that are at least 50 percent open to the sky with uniformly distributed openings;

D. Swimming pools and hot tubs that are not enclosed in roofed structures or decks; and

E. One small, non-habitable accessory structure under 120 square feet. If there is more than one such structure on the lot, only one structure shall be excluded in the calculation of lot coverage.

Figure 15.04.103.110: Determining Lot Coverage

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A. Corner Lot. The front of a lot is the narrowest dimension of the lot with street frontage.

B. Through Lot. The front yard of a through lot abuts the street that adjoining lots use to provide primary access into the dwelling.

A setback line defining a required yard is parallel to and at the specified distance from the corresponding front, side, or rear lot line. The following regulations for determining yards apply when a lot abuts a proposed street or alley.

A. Yards Abutting Planned Street Expansions. If a property abuts an existing or proposed street for which the existing right-of-way is narrower than the right-of-way ultimately required for the street, the required setback shall be established from the future right-of-way rather than the property line.

B. Yards on Alleys.

1. If a side lot line abuts an alley, the yard shall be considered an interior side yard rather than a corner side yard.

2. In computing the minimum yard for any lot where such yard abuts an alley, no part of the width of the alley may be considered as part of the required yard.

C. Measuring Setbacks. Setbacks shall be measured as the distance between the nearest lot line and the closest point on the exterior of a building or structure along a line at right angles to the lot line. Setbacks shall be unobstructed from the ground to the sky except where allowed pursuant to Section 15.04.601.020 (Building Projections into Yards), subject to compliance with the Building Code.

Figure 15.04.103.130: Determining Setbacks (Yards)

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The calculations of measurements related to signs are described in Article 15.04.609 (Signs).

For the purpose of calculating required parking lot landscaping, parking lot areas are deemed to include parking and loading spaces as well as aisles, vehicle entry and exit areas, and any adjacent paved areas. Parking lot area does not include enclosed vehicle storage areas.

The minimum distance shall be measured from the edge of any table, chair, bench, planter, or other appurtenance used as part of an outdoor dining area to any obstruction within the sidewalk area.

Figure 15.04.103.160: Measuring Pedestrian Clearance

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