Salt Lake County
Planning and Development Services Division
Residential Compatibility Overlay Zone
(RCOZ)
Step-by-Step Users Guide
November 30, 2009
RESIDENTIAL COMPATIBILITY
OVERLAY ZONE
OPTION B - USERS GUIDE
DEVIATIONS
from
GENERAL STANDARDS
based on
NEIGHBORHOOD COMPATIBILITY
Applies to:
• MAXIMUM BUILDING
HEIGHT
•
MAXIMUM LOT
COVERAGE
• MINIMUM FRONT SETBACK
and
•
1.
MINIMUM SIDE SETBACK
Zoning
1


Consult Salt Lake County’s Interactive Zoning Map at www.pwpds.slco.org
to determine whether or not the property you’re interested in is situated
within the Residential Compatibility Overlay Zone (RCOZ).
The same map will show which of the following zones also apply to the
property.





2.





R-1-5
R-1-6
R-1-8
R-1-10
R-1-21
R-1-43
R-2-6.5
R-2-8
R-2-10
A-1
Development Characteristics
The development standards of RCOZ apply to all single-family and two-family
residential improvements of the following types. Indicate the type that applies:
 An addition to an existing home.
 A residential remodel w/exterior modifications or expansions.
 A residential renovation w/exterior modifications or expansions.
 New home construction wherein an existing home on the property is
demolished and a new home is built (not the same as a “remodel”).
 New home construction on a vacant lot.
 Renovation, remodeling or new construction of a detached garage or other
accessory structure.
3.
The Residential Compatibility Overlay Zone (RCOZ) provides a three-tiered
approach for achieving zoning approval prior to building permit authorization:
•
OPTION A = Strict compliance with established setback, building envelope,
building height and lot coverage standards.
•
OPTION B = Property owner deviations from these standards based upon
compatibility with existing homes in the immediate neighborhood.
•
OPTION C = A public hearing process before the Planning Commission
allowing for a property owner to apply for a special exception on the basis of
unusual or extraordinary circumstances.
2
Application
•
No public hearing is required for Option B review.
•
Final disposition is determined at a division director / staff level.
•
Accurate information on the homes selected for comparison must be provided
at the time the request is applied for.
•
Consultation with staff prior to the preparation of final plans is encouraged.
Evidence
•
It is the responsibility of the applicant to provide evidence of compliance with
Option B criteria.
•
Such evidence may include reliable photographic, engineering, architectural
or other data.
Allowed Deviations - Under Option B a property owner may be granted approval
of the following:
•
An increase in Maximum Building Height of up to 5 feet.
•
An increase in lot coverage of up to 15%.
•
A reduction in front setback requirements.
•
A reduction in side setback requirements to no less than six feet.
Restrictions - Deviations from any of the following are prohibited under Option B:
•
Rear Yard.
•
Building Envelope.
•
Mass and Scale.
•
Accessory Building.
3
Demonstrating neighborhood compatibility of the dwelling improvements that
you wish to make will require you as the applicant to select the six lots within
the “proximate neighborhood”, as defined below, that best illustrate existing
area home improvements that now exceed what would be allowed under strict
compliance with RCOZ standards.
“Proximate neighborhood” means every residential lot, excluding the subject
lot, which is within the following distance from the subject property.
Zone
Proximate
Neighborhood
Zone
Proximate
Neighborhood
R-1-5
100 ft.
R-1-43
300 ft.
R-1-6
100 ft.
R-2-6.5
100 ft.
R-1-8
150 ft.
R-2-8
150 ft.
R-1-10
175 ft.
R-2-10
175 ft.
R-1-21
200 ft.
A-1
175 ft.
An example of lots situated within the “proximate neighborhood” of a
property situated in an R-1-10 zone is shown below:
For administrative relief under Option B it is required that homes on the
same six lots be used for comparison.
4
Option B Provisions for Increased Building Height

Accurately determine the top-of-ridge heights of the selected homes.

If a licensed surveyor is used to determine those heights, have the surveyor
certify the accuracy of the submitted documentation. Photographic,
engineering, architectural and other forms of documentation may also be
provided.

Add the individual dwelling heights together.

Divide that total by 6.The resulting figure is the average building height of
the selected homes.
Maximum building height under Option B is equal to the lesser of. . .
The maximum building height indicated below for the zone in which the property
is situated
Zone
Maximum
Building Height
Zone
Maximum
Building Height
R-1-5
33 ft.
R-1-43
40 ft.
R-1-6
33 ft.
R-2-6.5
33 ft.
R-1-8
33 ft.
R-2-8
33 ft.
R-1-10
35 ft.
R-2-10
35 ft.
R-1-21
37 ft.
A-1
35 ft.
or
Three feet, plus the average building height of the six selected homes.
5
For example, if;
•
The maximum building height specified in the above Table is
35 feet for a property in the R-1-10 zone, and
•
the average building height of the six selected homes from the
proximate neighborhood equals 32 feet, and
•
that average is added to the base 3 feet used as a starting point
in Option B,
then, the maximum building height based on both assessments
equals 35 feet.
If, on the other hand, the average building height of the six
selected homes equals 34 feet, and that average is added to the base
3 feet used as a starting point in Option B, and the combined total
equals 37 feet, then
The maximum building height is nonetheless restricted to 35 feet
since the ordinance (see §19.71.040.D.1) establishes that height as
the lesser of the two assessments.
For the purpose of calculating maximum building height only, an
immediately adjacent multi-resident structure such as an apartment
or condominium building may be considered as a comparable
structure within the proximate neighborhood.
6
Option B Provisions for Increased Lot Coverage
Lot coverage is “. . . a measure, expressed as a percentage, of how much of
the property may be covered by building improvements . . .”
•
B
oth the primary dwelling and all accessory buildings are considered in
the calculation.
•
S
idewalks, driveways, patios, decks, open porches and all other
impervious improvements (solid surfaces that prohibit water infiltration
into the ground) are excluded from this calculation in RCOZ.
To determine the maximum lot coverage allowed under Option B,
proceed as follows:

Go to the office of the Salt Lake County Assessor (Room N2300,
2001 South State Street, Salt Lake City, Utah) or visit the website of
that office at www.assessor.slco.org to obtain information on the lot
coverage of each of the six properties selected for comparison under
Option B.

If the calculations are to be completed from the web site, select the
Parcel Characteristics link in the upper right-hand corner of the Parcel
Value Summary page for the first property for which lot coverage data
is to be determined.

The Parcel Characteristics link takes you to a page entitled Parcel
Details and Valuation Information.

In the top center column of that page, under the heading for Property
Address, is a line for Total Acreage.

Multiply that number by 43,560. The result is the size of the property
in square feet.

In the column on the left of the page entitled Residence Record go to
the line designated as Above Grade Area. The figure provided
7
represents the size of the building footprint of the main dwelling on
the property and is expressed in square feet.
8

Go to the lower half of the center column on the page and, under the heading
of Detached Structure, find the dimensions of the structure under the headings
of Measure 1 and Measure 2.

Multiply Measure 1 by Measure 2 to determine the building footprint size of
the detached structure.

Add the building footprint sizes of the main dwelling and detached
structure(s) on the property for the total land area (in square feet) covered by
building improvements.

Divide this number by the size of the property in square feet. The resulting
figure is the lot coverage for that particular property.
For example, if
•
The first of the six properties being evaluated is 0.26 acre / 11,326 square feet
in size, and
•
The above grade area of the main dwelling is 2,650 square feet, and
•
The detached structure on the property is 576 square feet,
Then,
• The total size of building improvements on that property equals 2,650 + 576 =
3,226 square feet
•
The lot coverage of the first property used here to illustrate this approach
equals the above figure (3,226 square feet) divided by the size of the property
in square feet (11,326 square feet) = 28.5 %

Repeat this calculation process for each of the six properties that you would
like to use for comparative purposes for an increase in lot coverage under
Option B.

Add the lot coverage percentages calculated for the six chosen properties and
divide by six.

The resulting figure is the average lot coverage for the chosen properties.
9
The maximum lot coverage allowed under Option B is 1.15 times the average of
the above-calculated lot coverage percentages. Under no circumstances, however,
may that percentage exceed the percentage specified below for the zone in which
the property is situated. (see §19.71.040 Table I, column (e))
Zone
Maximum
Lot Coverage
Zone
Maximum
Lot Coverage
R-1-5
40%
R-1-43
28%
R-1-6
40%
R-2-6.5
45%
R-1-8
38%
R-2-8
43%
R-1-10
36%
R-2-10
40%
R-1-21
30%
A-1
36%
If, for example,
•
The average lot coverage of the six selected properties is 31.4%, and
•
The maximum lot coverage allowed under Option B is equal to1.15 times that
average,
Then,
•
The maximum lot coverage for the subject property on the basis of this
calculation would be 1.15 x 31.4 = 36% = 3,600 square feet (presuming that
the subject property in this instance is 10,000 square feet in size).
10
Since,
Table I of the adopted RCOZ ordinance (see §19.71.040) caps the maximum lot
coverage permitted in the R-1-10 zone under Option B to 36% for a property in the
R-1-10 zone,
Then,
•
The maximum lot coverage allowed for the subject property in this example
equals 36%, since both the calculations and the ordinance provide the same
results.
•
I
t is important to note again that this percentage applies to both
the primary dwelling and all accessory buildings.
•
36% of the land area used in this example (10,000 square feet) equals 3,600
square feet of land upon which property improvements (includes both the
dwelling and any accessory structure(s)) may be constructed.
•
By comparison, strict compliance with the adopted standards of Option A
would limit the lot coverage of the property used in this example to 31% or a
total building footprint size of 3,100 square feet for all building improvements
on the property.
11
Option B Provisions for Reduced Front Yard Setbacks
•
A setback, or yard, is “. . . a space on a lot, other than a court, that is
unoccupied and unobstructed from the ground upward by buildings or
structures. . .” (see 19.04.560: Yard).
•
A front yard is “. . . a space on the same lot with a building, between the
front line of the building and the front lot line, and extending across the full
width of the lot. The "depth" of the front yard is the minimum distance
between the front lot line and the front line of the building. . .” (see 19.04.565:
Yard, front).
The required front yard for properties in the Residential Compatibility Overlay
Zone (RCOZ) under Option A is as specified in the underlying zone.
Zone
Front Yard
(setback)
Zone
Front Yard
(setback)
R-1-5
20 ft.
R-1-43
30 ft.
R-1-6
25ft.
R-2-6.5
25 ft.
R-1-8
25 ft.
R-2-8
30 ft.
R-1-10
30 ft.
R-2-10
30 ft.
R-1-21
30 ft.
A-1
30 ft.
Under Option B an applicant may reduce the depth of the front yard or setback
based upon compatibility with existing homes in the immediate neighborhood.
As is the case with Option B provisions for increased building height and lot
coverage, the degree of flexibility available with regards to a reduction in front
yard requirements is equal to the average of the front setbacks of residential
structures that are on six lots of applicant’s choice.
It is important to note again that for administrative relief under Option B only
the homes on the same six lots from the “proximate neighborhood” (see Page 4 of
this User Guide) may be used for comparison, whether solely for a reduction in
yard setbacks or for increases in building height or lot coverage.
12
Option B Provisions for Reduced Side Yard Setbacks
•
A setback, or yard, is “. . . a space on a lot, other than a court, that is
unoccupied and unobstructed from the ground upward by buildings or
structures. . .” (see 19.04.560: Yard).
•
A side yard is “. . . a space on the same lot with a building, between
the side line of the building and the side lot line, and extending from the
front yard to the rear yard . . .” ( see 19.04.575: Yard, side).
The total side yard requirements for a main structure in the Residential Compatibility
Overlay Zone (RCOZ) must equal or exceed twenty-five percent (25%) of the width
of the lot on which the structure is situated.
For the purposes of RCOZ, Lot Width is defined as the diameter of the largest circle
that can be inscribed entirely within the lot. Image 1 illustrates this calculation:
Image 1
Lot Width Measurement
In the preceding example 25% of the width of the lot, shown here to be 102 feet, equals
25.5 feet. Since the 25% lot width requirement applies to the total side yard requirements
for the main structure, the setback on each side may be distributed as the property owner
wishes so long as, under Option B, no side yard is less than 6 feet.
13
The following illustrates examples of this calculation for lots of varying widths:
0.25 x 55 ft = 14ft. (total)
0.25 x 60 ft = 15ft. (total)
0.25 x 65 ft. = 16 ft. (total)
0.25 x 80 ft. = 20 ft. (total)
0.25 x 100 ft. =
0.25 x 110 ft. =
0.25 x 125 ft. =
0.25 x 150 ft. =
25 ft. (total)
27.5 ft. (total)
31.25 ft. (total)
37.50 ft. (total)
It is important to note that in the measurement of lot width those portions of a lot
traversed or encumbered by streams, floodplains, wetlands, areas of thirty percent
slope or greater, or other natural hazard areas are excluded from such measurement.
It is further important to note that structural encroachments into required side yards
in the Residential Compatibility Overlay Zone (RCOZ) are restricted as follows:
•
Architectural features such as bay windows, chimneys, etc. may not encroach
into required side yards.
•
Attached air conditioning units, electrical boxes, utility meters and the like may
encroach.
•
Roof overhangs or eaves that extend no more than two feet into the area of the
minimum side setback may also encroach.
Image 2 illustrates one scenario for side yard distribution for the 102 ft. wide lot
depicted in Image 1.
Image 2 - Setbacks
14
Image 2 – Side Yard Distribution
Under Option B a reduction in a required side yard setback for the main
structure is allowed subject to the following:
•
Proof of compatibility with existing side yard setbacks for homes in the
immediate neighborhood. As with allowed variations of building height,
lot coverage and front yard setbacks under Option B, the degree of
flexibility allowed is equal to the average of the side yard setbacks of
residential structures that are on six lots of applicant’s choice.
•
Retention of a minimum twenty-five percent of lot width for the
combined side yard setbacks.
(That is to say that while the setback on one side of the dwelling may be
reduced under Option B, the setback on the other side of the dwelling
would have to be increased by an equal amount so as to retain a total
calculation of side yards equal to twenty-five percent of the width of the
lot. As a result, Option B allows for a shift in setbacks rather than an
outright reduction).
•
Maintenance of no less than a six foot separation between the structural
improvements and the adjacent side property line.
Note that for administrative relief under Option B only the homes on the
same six lots from the “proximate neighborhood” (see Page 4 of this User
Guide) may be used for comparison, whether solely for a reduction in yard
setbacks or for increases in building height or lot coverage.
Rear Yard provisions under Option B
A rear yard is “. . . a space on the same lot with a building, between the rear line of
the building and the rear lot line, and extending the full width of the lot. The "depth"
of the rear yard is the minimum distance between the rear lot line and the rear line of
the building. . .” (see 19.04.570: Yard, rear).
All zones
•
15 feet with a garage
15
•
30 feet without a garage
Building Envelope provisions under Option B
The Building Envelope (also referred to as a “graduated height envelope”) is
determined as follows:
a.
Establish the “story pole” or vertical wall height of the building envelope at
each side lot line.

On the building plan sheet that illustrates the front elevation of the home
indicate the original ground surface or existing grade of the property (the
“lay of the land” prior to any cuts, fills or other surface alterations) as well
as the side property lines or boundaries.
Image 3
Existing Grade & Side Property Lines
16

From each side lot line draw a vertical line scaled to equal 8
feet in height.

The scale used for drawing this vertical line must be the same
as that used for drawing the home. (i.e. an architect’s scale with calibrations
of 1/16 in. = 1 ft . . . 1/8 in. = 1 ft. . . . ¼ in. = 1 ft., etc.)

The point of beginning (low point) for each vertical line is
from the original grade of the property at the building line or front setback
point of intersection with each side lot line.
Image 4
Story Pole Height
17
b.
Establish the diagonal “tent side” projections for the building
envelope.

F
rom the top of each “story pole” draw a line at a 45 degree angle towards
the center of the lot. It is not necessary for these lines to project upward to a
point of intersection . . . only to a height that coincides with the maximum
building height allowed in the zone in which the property is situated. (see
#4 below)
Image 5
Diagonal “tent side” Projections
18
c.
Establish the top line or “cap” of the building envelope illustration.

Draw a vertical line at each side wall of the home beginning at the lowest
point of original grade at that point. The height of each line, drawn to scale,
is as specified under Maximum Building Height below.

The “roof” or “cap” for the building envelope illustration is
created by drawing a line connecting the two top points of the abovedescribed lines at each side wall of the home.

To complete the “cap” or top of the building envelope illustration,
project or extend the line outward to a point of intersection with each
above-described “tent side” projections for the building envelope.
Image 6
Top “Cap”/Completed Building Envelope - Front
19
The Building Envelope as described above defines an “imaginary window”
within which the proposed home is to be contained or fit.
20
NOTE – THE BUILDING ENVELOPE PROCESS DESCRIBED
ABOVE NEEDS TO BE COMPLETED FOR EACH SEPARATE
BUILDING ELEVATION (FRONT, REAR, LEFT SIDE, RIGHT
SIDE)
Image 7 - Completed Building Envelope – Right Side
Image 8 - Completed Building Envelope – Rear
Image 9 - Completed Building Envelope – Left Side
21
As illustrated by the preceding images, the dwelling shown, while
within the building envelope from the front elevation perspective,
encroaches beyond the limits allowed when seen from the right side,
rear and left side perspectives. Plan modifications would be required
to accurately reflect the existing topography of the site if project
approval is to be granted.
Dormer Encroachments into the Building Envelope
A dormer that complies with the following standards may exceed the
graduated height envelope:

The width of the dormer is no more than fourteen feet;

With multiple dormers, the distance to the front or side edges of the
roof is at least one-half the distance between dormers; and

he dormer is no higher than the ridge of the roof.
Image 7
Dormer Encroachments
22
Gabled Roof Encroachments into the Building Envelope
A gable that complies with the following standards may exceed the
graduated height envelope:

The height of the gable is no more than 1.75 times higher than the
point where the graduated height envelope intersects the gable;
and

The height of the gable is less than the maximum building height.
Image 8
Gable Encroachments
23
24
Mass and Scale
So as to avoid a large, continuous building mass of uniform height, the
following architectural considerations shall have been incorporated into
the design of the home at horizontal intervals or wall segments of no
more than forty feet:

A minimum 18-inch break in the roofline

An architectural element such as:
 An overhang
 A projection
 An inset
 A material and textural change.
Image 9
Building Articulation
The intent and purpose of these features is to create shadow patterns along the
elevation of the building. The elements required by this section are in addition
to all other requirements under this Part.
25