2019-16_2229 Mariposa Avenue_Disposition PacketN O T I C E
FINDINGS AND DECISION OF THE CITY OF BOULDER BOARD OF ZONING
ADJUSTMENT DISPOSITION OF ZONING CASE
DOCKET NUMBER BOZ2019-16
CONCERNING THE APPLICATION FOR A VARIANCE OF THE SETBACK REQUIREMENTS OF SECTION
9-7-1, B.R.C. 1981 AT 2229 MARIPOSA AVENUE OF KATRINA MITCHELL, WHOSE MAILING ADDRESS IS
2229 MARIPOSA AVENUE, BOULDER, COLORADO 80302
On September 12, 2019, the City of Boulder Board of Zoning Adjustment, a quorum being present, held a
public hearing, after giving notice as required by law, on the application for the following variance:
As part of a proposal to modify an existing non-standard accessory building with the intent of converting it into a
1.5-story accessory dwelling unit (ADU), the applicant is requesting a variance to the side (east) yard setback in
order to meet the minimum interior side setback requirement for accessory structures in the RL-1 zoning district.
The resulting side setback will be approximately 1.2 feet (at the closest point) where 3 feet is required and
approximately 1.2 feet exists today. No expansion of the existing footprint to the building is proposed as a part of
the conversion to an ADU. Section of the Land Use Code to be modified: Section 9-7-1, BRC 1981.
Based on our field investigation and the relevant testimony, exhibits, and other evidence introduced at the
hearing, and in accordance with the applicable provisions of the Boulder Revised Code, 1981, we find by a
preponderance of the evidence that the criteria for granting a variance have been met, and grant the variance as
requested:
This variance is limited to the use and structure for which it was requested, including the location on the lot and
maximum height, as approved by the Board of Zoning Adjustment.
This variance was approved by the vote of 5-0.
EXECUTED this 12th day of September 2019, effective as of, September 12, 2019.
Jack Rudd, Presiding Officer of the Board at the Meeting
By: __________ _______________________________
Robbie Wyler, Secretary to the Board of Zoning Adjustment
This decision constitutes a final decision as of the date of the hearing at which it was reached. If a variance was
granted, the variance expires within 180 (one hundred eighty) days from the date on which it were granted unless a
building permit for such variance is applied for within such period.
CITY OF BOULDER
Planning and Development Services
1739 Broadway, Third Floor • P.O. Box 791, Boulder, Colorado 80306-0791
phone 303-441-1880 • fax 303-441-3241 • email plandevelop@bouldercolorado.gov
www.boulderplandevelop.net
BOZA Disposition of Approval Page 1 of 22
BOZA Disposition of Approval Page 2 of 22
2
APPLICATION TYPES (Check All That Apply For This Application)
Setback (BRC 9-7-1)
Porch Setback & Size (BRC 9-7-4)
Building Separation (BRC 9-7-1)
Bulk Plane (BRC 9-7-9)
Side Yard Wall Articulation (BRC 9-7-10)
Building Coverage (BRC 9-7-11 or BRC 9-10)
Floor Area Ratio (BRC 9-8-2)
Parking in Front Yard Landscape Setback (BRC 9-7-1 & 9-9-6)
Size and Parking Setback Requirements for Accessory Units (BRC 9-6-3)
Cumulative Accessory Building Coverage (BRC 9-7-8)
Mobile Home Spacing Variance (BRC 9-7-13)
Use of Mobile Homes for Non-Residential Purposes (BRC 10-12-6)
Solar Exception (BRC 9-9-17)
Sign Variance (BRC 9-9-21)
BOZA Disposition of Approval Page 3 of 22
BOZA Disposition of Approval Page 4 of 22
BOZA Disposition of Approval Page 5 of 22
SAWHORSE-6 designs 303.579.1667
BOZA Setback Variance Statement
ADU 2019-00070, 2229 Mariposa Ave. 8.12.19
Background
Katrina Mitchell has owned and lived at 2229 Mariposa Ave since 2005. She would like to
convert her existing single story brick garage into an ADU with a storage loft. The existing 3-
bedroom primary house would then be rented at fair market value while she resides in the
ADU during retirement.
Criteria for Variance
The garage was built along with the house in 1951. Having a footprint of 444 SF, the garage
measures 1.2’ from the east property line, meeting neither the 0’ or 3+’ setback currently
required for accessory buildings in the RL-1 zoning district. Our intent with the conversion was
to maintain the nonstandard setback as allowed per B.R.C. 9-10-3(2).
Specifically, the structural brick walls and associated foundation will remain intact throughout
the conversion. The brick is in good condition and is the most durable cladding for the
location and will require the least amount of maintenance over time. Given the tight
alignment with the property line Katrina has also entered into an agreement with her neighbor
to the east, at 2233 Mariposa, allowing for a maintenance easement.
During the Administrative Review the Planning & Development department asked for a BOZA
disposition regarding the non-standard setback because the function of the building was
changing from an Accessory to an ADU. During the review we easily met all other building
department and zoning concerns.
Character of the Neighborhood
The neighborhood (including the immediate neighboring lots) has many accessory structures
that are in the 0’-3’ setback. Leaving the building intact with the original materials that the
primary house is built with will preserve the character of the neighborhood.
Thank you for your review of this issue.
Owner,
Katrina Mitchell
Best,
JD Signom, AIA
SAWHORSE-6 a r c h i t e c t u r e + p l a n n i n g
jd@sawhorse6.com
303.579.1667
BOZA Disposition of Approval Page 6 of 22
BOZA Disposition of Approval Page 7 of 22
BOZA Disposition of Approval Page 8 of 22
BOZA Disposition of Approval Page 9 of 22
BOZA Disposition of Approval Page 10 of 22
BOZA Disposition of Approval Page 11 of 22
BUILDING COVERAGE:
FLOOR AREA TOTAL: 1820 SF
MAX FAR ALLOWED: 3456 SF
PRIMARY RESIDENCE (SINGLE STORY):1271 SF
ADU MAIN FLOOR AREA: 411 SF
ADU FLOOR AREA IN LOFT: 101 SF
ADU STAIR AREA: 37 SF
COMBINED HIGH VOL. SPACE: 0 SF
FLOOR AREA :
SQUARE FOOTAGE SUMMARIES
EXISTING COVERAGE: 1756 SF
MAX COVERAGE ALLOWED:2406 SF
Primary Structure:1271 SF
Accessory Existing: 444 SF
New ADU porch roof: 41 SF
SITE AREA: 6,782 SF = .155 ACRE
(NON-STANDARD LOT SIZE)
ZONING: RL-1
MAX ACCESSORY HEIGHT: 20'
Scale
Designed by
Date
2126 Columbine Avenue
Boulder, CO 80302
303.579.1667
1/4" = 1'-0"0-0-CVR-
Gen. Notes +
Project Info 2229 Mariposa Ave.8.12.19
JD
PROJECT TEAM CONTACT INFO
OWNERS:
KATRINA MITCHELL
2229 MARIPOSA AVE, BOULDER, CO 80302
P: 303-669-9905
KATRINALMITCHELL@GMAIL.COM
ARCHITECT: SAWHORSE-6 ARCHITECTURE & PLANNING
JD SIGNOM, AIA
2126 COLUMBINE AVE
BOULDER, CO 80302
P: 303-579-1667
JD@SAWHORSE6.COM
SURVEYOR: SCOTT, COX & ASSOCIATES
JOHN BURI
1530 55TH ST.
BOULDER, CO 80303
P: 303-444-3051
BURI@SCOTTCOX.COM
PROPERTY INFORMATION
2229 MARIPOSA AVE
BOULDER, CO 80302
STR: T1SR70W SEC 06
SUBDIVISION: INTERURBAN PARK - BO
LEGAL DESC: LOT 15 BLK 6 INTERURBAN PARK
PROJECT DESCRIPTION
CONVERT EXISTING SINGLE STORY GARAGE TO ADU
WITH LOFT.
VICINITY MAP: NTS
Sheet List
Sheet
Number Sheet Name
V100 Survey
A100 Architectural Site Plan
A103 Primary Residence - Plan
A104 Accessory - Existing Plan
A104.5 ADU - 1st Floor Plan - Proposed
A105 ADU - Loft Plan - Proposed
A106 Proposed New ADU Roof Plan
A200 Elevations
A201 Elevations
A300 Building Sections BOZA Disposition of Approval Page 12 of 22
BOZA Disposition of Approval Page 13 of 22
MARIPOSA AVENUE
25'
LOWEST POINT IN 25'
ELEV.=5403.6'
N89°46'05"E 50.21'(M)N0°04'01"W 135.05'(M)S0°03'31"E 135.05'(M)PP OHE4 B
5429.48
590
24" TREE
CURBWALK
16" TREE
26" TREE 18" TREE
MARIPOSA AVENUE
25'
LOWEST POINT IN 25'
ELEV.=5403.6'
24" TREE
16" TREE
26" TREE 18" TREE
5406 54055407540554065 4 06
5 4 0 45405540554065
4
0
5
CURBWALK
N
OFF STREET PARKING. PARALLEL PARKING
APPROACH (0° PARKING ANGLE). NEW
GRAVEL PAD TO BE INSTALLED MINIMUM OF
23'x9' PER BRC 9-9-6 TABLE 9-6.
NEW PRIVACY FENCE TO DEFINE PRIVATE OPEN SPACE
265 SF OF PRIVATE OPEN SPACE
NEW PRIVATE ENTRY TO BE ESTABLISHED
PROPERTY LINES
EXISTING GARAGE MADE OF BUFF COLORED BRICK TO BE
CONVERTED INTO ADU. GARAGE APPEARS TO BE BUILT AT
THE SAME TIME AND WITH THE SAME MATERIAL AS THE
PRIMARY STRUCTURE. 444 SF OF BUILDING COVERAGE.
CURRENTLY USED FOR STORAGE.
EXISTING ONE STORY BUFF
COLORED BRICK BUNGALOW
1271 SF OF BLDG COVERAGE.
BUILT IN 1951.
(NO CHANGES PROPOSED AT
THIS TIME)PLANTEROVERHEAD POWER, PHONE & CABLE
MINISPLIT HEAT PUMP
EDGE OF NEW ROOF ABOVE
9' x 23' PARKING 9' x 23' PARKING
10.9'5'28.0'42.9'64.2'23.8'89.1'APPROXIMATE DRIP
LINE OF EXISTING TREES
EXISTING PAVERS TO REMAIN
GATE
REPLANT AREA WITH PERENNIALS
AND NON-TURF GROUNDCOVER
TO MEET BRC 9-9-12.
25' REAR YARD SETBACK
23 SF EXISTING ADU IN REAR YARD SETBACK
LANDSCAPE NOTE:
EXISTING LANDSCAPE TO REMAIN LARGELY INTACT.
28.9'
1.2'
PROPERTY LINES
EXISTING
SINGLE STORY
GARAGE 444 SF
EXISTING ONE STORY BUFF
COLORED BRICK BUNGALOW
1271 SF OF BLDG COVERAGE.
BUILT IN 1951.
(NO CHANGES PROPOSED AT
THIS TIME)PLANTEROVERHEAD POWER, PHONE & CABLE
FENCE
GATE
GATE
D R I V E W A Y (PERMEABLE)Scale
Designed by
Date
2126 Columbine Avenue
Boulder, CO 80302
303.579.1667
1" = 20'-0"0-0A100
Architectural Site
Plan 2229 Mariposa Ave.8.12.19
JD
1" = 20'-0"1 Site Plan - Proposed
1" = 20'-0"2 Site Plan - Existing
BOZA Disposition of Approval Page 14 of 22
?W/D8' - 6"12' - 9 1/2"12' - 3 1/2"10' - 10"11' - 4 1/2"6' - 7"11' - 4"6' - 5 1/2"9' - 6"5' - 5"
15' - 11"
5407' - 2 1/2"
102' - 1 1/4"
KITCHEN
LIVING ROOM
DINING
BEDROOM 1
BEDROOM 2
BEDROOM 3
***EXISTING PRIMARY STRUCTURE -- TO REMAIN UNCHANGED
N
ROOF OVERHANG
Scale
Designed by
Date
2126 Columbine Avenue
Boulder, CO 80302
303.579.1667
1/8" = 1'-0"0-0A103
Primary Residence
- Plan 2229 Mariposa Ave.8.12.19
JD
1/8" = 1'-0"1 1st Floor
NOTES:
-USGS SURVEY: 5405' 1-1/4" = 100'
-LOW POINT WITHIN 25' = 5403.6'
-ADU DWELLING TO HAVE 13D FIRE
SUPRESSION SYSTEM
-ADU WILL MEET 2017 COBECC
BOZA Disposition of Approval Page 15 of 22
N
EXISTING OVERHEAD DOOR TO BE REMOVEDEXISTING DOOR TO BE REMOVED
EXISTING WINDOW TO BE
CONVERTED TO MAIN ENTRY
100' - 0"
EXISTING ROOF OVERHANG.
ENTIRE ROOF TO BE REMOVED.
1 2
A
B
C 11' - 11"10' - 1"22' - 0"20' - 2"
5405' - 1 1/4"
EXISTING STRUCUTRAL BRICK
& BLOCK WALL TO REMAIN.
Scale
Designed by
Date
2126 Columbine Avenue
Boulder, CO 80302
303.579.1667
1/4" = 1'-0"0-0A104
Accessory -
Existing Plan 2229 Mariposa Ave.8.12.19
JD
1/4" = 1'-0"1 Accessory - Existing Plan
NOTES:
-USGS SURVEY: 5405' 1-1/4" = 100'
-LOW POINT WITHIN 25' = 5403.6'
-ADU DWELLING TO HAVE 13D FIRE
SUPRESSION SYSTEM
-ADU WILL MEET 2017 COBECC
BOZA Disposition of Approval Page 16 of 22
UP
?W 25'22.1'SCP SCA NAIL
24" TREE5405
A201
A201
A2002
A200
2
1
1
N
5405' - 1 1/4"
100' - 0"
MAIN FLOOR
411 SF
BATH
44 SF
SLEEPING AREA
80 SF
LIVING ROOM
113 SF
KITCHEN
85 SF
EDGE OF LOFT ABOVE
3' - 0"11' - 7"18' - 6"
5' - 0"9' - 0"1' - 8"1' - 8"INDUCTION COOKTOP
1
A300
REF.7' CELING HEIGHT
BELOW LOFT
MINI-SPLIT HEAT PUMP
ROOF OVERHANG ABOVE
258 SF OF PATIO SPACE
7' - 4"5' - 7"
1 2
A
B
C
20' - 2"11' - 11"10' - 1"22' - 0"3' MINIMUM SETBACK FOR PENETRATIONS
PER IRC 2012 TABLE R302.1(2)
-NO ROOF OVERHANGS OR PENETRATIONS
WITHIN SETBACK
INSULATEED FURRING WALLS ADDED TO
INTERIOR OF STRUCTURE.
HATCHED AREA (33 SF)
UNINHABITABLE UNDER STAIR AREA
DOES NOT CONTRIBUTE TO FLOOR
AREA SEE 1/A300 FOR SECTION
LEAVE BRICK WALL AND FOUNDATION
FULLY INTACT PER BRC 9-10-3.(a)(2)(A)
1' - 8"
Scale
Designed by
Date
2126 Columbine Avenue
Boulder, CO 80302
303.579.1667
1/4" = 1'-0"0-0A104.5
ADU - 1st Floor
Plan - Proposed2229 Mariposa Ave.8.12.19
JD
1/4" = 1'-0"1 ADU Floor Plan - Proposed
NOTES:
-USGS SURVEY: 5405' 1-1/4" = 100'
-LOW POINT WITHIN 25' = 5403.6'
-ADU DWELLING TO HAVE 13D FIRE
SUPRESSION SYSTEM
-ADU WILL MEET 2017 COBECC
PRIVACY FENCE
BOZA Disposition of Approval Page 17 of 22
DN
?W
A201
A201
A2002
A200
2
1
1
STORAGE LOFT 101 SF
OF CONTRIBUTING
FLOOR AREA. SEE
SECTION A1/300
OPEN TO BELOW
MAX. CLG
HEIGHT 15.2'3' - 5"1' - 5"8' - 2"RAILING
1
A300
107' - 11"
N
1 2
A
B
C
10' - 4"
HATCHED AREA IS 15 SF OF UNINHABITABLE
SPACE HAVING A CEILING HEIGHT OF LESS
THAN 6' AND DOES NOT CONTRIBUTE TO
FLOOR AREA.
EDGE OF ROOF BELOW
OPEN TO BELOWPORCH ROOF 41 SF BELOW.
STAIR AREA 34SF
Scale
Designed by
Date
2126 Columbine Avenue
Boulder, CO 80302
303.579.1667
1/4" = 1'-0"0-0A105
ADU - Loft Plan -
Proposed 2229 Mariposa Ave.8.12.19
JD
1/4" = 1'-0"1 ADU - Loft Plan - Proposed
NOTES:
-USGS SURVEY: 5405' 1-1/4" = 100'
-LOW POINT WITHIN 25' = 5403.6'
-ADU DWELLING TO HAVE 13D FIRE
SUPRESSION SYSTEM
-ADU WILL MEET 2017 COBECC
BOZA Disposition of Approval Page 18 of 22
25'
LOWEST POINT IN 25'
ELEV.=5403.6'
GS
5403.58
608
24" TREE
54075405WOOD FENCE23.8'23.9'1.2'
1.5'
A201
A201
A2002
A200
2
1
1
N
5421' - 11 1/2"9.3'16.4'6' - 6"
2" / 12"
1 2
A
B
C
ALL ROOF SLOPES
TO PROP LINE
ROOF NOTE:
ALL ROOF ASSEMBLIES TO BE
UNVENTED CLASS A. AS DESIGNED,
WITH A 2/12 PITCH THE ROOFING
MATERIAL WILL NOT BE VISIBLE
FROM THE GROUND IN ANY
DIRECTION.
HIGH POINT
Scale
Designed by
Date
2126 Columbine Avenue
Boulder, CO 80302
303.579.1667
1/8" = 1'-0"0-0A106
Proposed New
ADU Roof Plan2229 Mariposa Ave.8.12.19
JD
1/8" = 1'-0"1 Roof Plan
NOTES:
-USGS SURVEY: 5405' 1-1/4" = 100'
-LOW POINT WITHIN 25' = 5403.6'
-ADU DWELLING TO HAVE 13D FIRE
SUPRESSION SYSTEM
-ADU WILL MEET 2017 COBECC
BOZA Disposition of Approval Page 19 of 22
ADU
100' - 0"
T.O. Roof
116' - 10 3/16"
ADU T.O.W.
107' - 0"
ADU - Loft Plan -
Proposed
107' - 11"
NEW SECOND STORY
WITH SHIP LAP SIDING
EXISTING BUFF COLORED BRICK
NEW WINDOWS AND DOORS ALL AROUND
A B C
(E)
PORCH ROOF
ADU
100' - 0"
T.O. Roof
116' - 10 3/16"
ADU T.O.W.
107' - 0"
ADU - Loft Plan -
Proposed
107' - 11"
NEW CLASS A ROOFS
EXISTING BRICK TO REMAIN
NEW SIDING
ABC
FENCE BEYOND
NO OVERHANGS
ON LOWER ROOF
Scale
Designed by
Date
2126 Columbine Avenue
Boulder, CO 80302
303.579.1667
1/8" = 1'-0"0-0A200
Elevations 2229 Mariposa Ave.8.12.19
JD
1/8" = 1'-0"1 West Elevation
1/8" = 1'-0"2 East Elevation
NOTES:
-USGS SURVEY: 5405' 1-1/4" = 100'
-LOW POINT WITHIN 25' = 5403.6'
-ADU DWELLING TO HAVE 13D FIRE
SUPRESSION SYSTEM
-ADU WILL MEET 2017 COBECC
BOZA Disposition of Approval Page 20 of 22
ADU
100' - 0"
T.O. Roof
116' - 10 3/16"
ADU T.O.W.
107' - 0"
ADU - Loft Plan -
Proposed
107' - 11"
LOW POINT WITHIN 25'
5403' - 7"
6' PRIVACY FENCE FROM
PRIMARY RESIDENCE
2"
12"
2" / 12"
5418' - 11 1/4"5421' - 0 1/4"
5420' - 6 1/4"
PROPERTY LINE (NEAREST POINT TO STRUCTURE)
6' - 4"
14"
HEIGHT FROM
LOW POINT
5421' - 11 3/8"1' - 7 3/4"18' - 4 3/8"4 5 °12'BULK PLANE
1 2
ACCESSORY HEIGHT MAX.
20' PER BRC 9-7-1.
ADU
100' - 0"
T.O. Roof
116' - 10 3/16"
ADU T.O.W.
107' - 0"
ADU - Loft Plan -
Proposed
107' - 11"
2"
12"
2 " / 1 2 "
MINI-SPLIT HEAT PUMP
12
NO OVERHANGS
ON LOWER ROOF
Scale
Designed by
Date
2126 Columbine Avenue
Boulder, CO 80302
303.579.1667
1/8" = 1'-0"0-0A201
Elevations 2229 Mariposa Ave.8.12.19
JD
1/8" = 1'-0"2 South Elevation
1/8" = 1'-0"1 North Elevation
NOTES:
-USGS SURVEY: 5405' 1-1/4" = 100'
-LOW POINT WITHIN 25' = 5403.6'
-ADU DWELLING TO HAVE 13D FIRE
SUPRESSION SYSTEM
-ADU WILL MEET 2017 COBECC
BOZA Disposition of Approval Page 21 of 22
ADU
100' - 0"
T.O. Roof
116' - 10 3/16"
ADU T.O.W.
107' - 0"
ADU - Loft Plan -
Proposed
107' - 11"5' - 8"6' - 8" MIN.BATH
KITCHEN
BEYOND SLEEPING AREA
STORAGE LOFT
2"
12"
115' - 4"6'UNINHABITABLE SPACE
30"7'6'22"
Scale
Designed by
Date
2126 Columbine Avenue
Boulder, CO 80302
303.579.1667
1/4" = 1'-0"0-0A300
Building Sections2229 Mariposa Ave.8.12.19
JD
1/4" = 1'-0"1 Section at Stair
BOZA Disposition of Approval Page 22 of 22