00 - Planning Board - Study Session - Compatible Development in Single Family Neighborhoods - May 14, 2009
9
Central Records
Planning Boaj-d
Technical Study Session
May 14, 2009
Compatible Development in Single->raniily Neighborhoods
DRAFT Agenda
1. Single-Family Development Zoning Review (15 min.)
a. Regulatory standards that are currently reviewed
b. flow those standards are measured
c. Typical documentation requests
2. New Compatible Development Tools (30 min.)
a. FAR
L Definition
ii. Measured
b. Building Coverage
i. Definition
ii. Measured
c. Wall Articulation
i. Options
ii. Definitions of Wall Length and Wall Height
iii. Measurement of Height
iv. Measurement of Length
3. Sketch-Up Modeling (30 min.)
a. 7,000 square foot lot
i. Staff recommendation
ii. Council direction
b. 6,250 square root lot
i. Staff recommendation
ii. Co1111C1I direction
4. Planning Board Discussion (105 min.)
Total Agenda Time: 3 hours
CITY OF BOULDER
PLANNING BOARD AGENDA ITEM
MEETING DATE: May 14, 2009
AGENDA TITLE: Compatible Development Study Session - '.1'raining and discussion on
definitions and calculating Floor Area Ratios, Building Coverage and Wall Articulation
Standards.
REQUESTING DEPARTMENT:
Ruth McHeyser, Executive Director of Community Planning
David Driskel.l, Deputy Director of Community Planning
Susan Richstone, Long Range Planning Manager
Julie Johnston, Senior Planner
Brian Holmes, Zoning Administrator
Chris Toebe, Project Specialist
Mary Margaret Little, Planning Associate
EXECU'T'IVE SUMMARY:
The purpose of this item is to provide the Planning Board an opportunity to discuss with staff the
technical issues that relate to the use of floor area ratios, building coverages, and wall
articulation standards as regulatory tools in the Boulder Revised Code. The intent is to provide
the Planning Board with some training on the current practices of single-family development
building permit review as well as how the new regulations would change or alter the review
process. In particular, an overview of how these tools will be measured and defined will be
discussed-
BACKGROUND:
On March 3, 2009, City Council provided direction to staff on the regulatory tools to resolve the
issues of mass and scale of new home construction and additions outlined in the Compatible
Develol-nncnt in Single-Family Neighborhoods project. The direction was based on the strategy
developed by Winter & Company, which addressed the refined problem statement presented in
the January 12 Strategy Report, as well as the broad array of community feedback received to
date. The recommended strategy also considered council's goals and objectives for the project
including the need to maintain flexibility, provide for changing needs, promote variety and
ensure fairness.
The direction from City Council included a combination of floor area ratio, building coverage,
and wall articulation tools. The specific standards for each tool have yet to be agreed upon but
they arc intended to recognize traditional development patterns while providing flexibility for
additions and new construction that are compatible to their zoning district and lot size. Council's
direction included applying the tools to all single-family properties in the project area zone
districts, as follows (See Attachment A: Project Area Map):
AGENDA ITEM # 6A Page l
Residential -Rural I (RR-1)
Residential - Rural 2 (RR-2)
Residential Estate (RE)
Residential -Low 1 (RL-1)
Residential - Low 2 (RL-2): Single-family properties that are not currently governed by a
Planned Development (PD), Planned Residential Development (PRD), or annexation agreement.
Residential -Mixed 1 (RMX-1): Only existing single-family properties.
It is the combination of tools and their interaction with each other that begins to address
compatibility between lots and within neighborhoods. For example, floor area ratio deals with
the overall mass of the structure; building coverage detennines how much of the lot this mass
can utilize; and the wall articulation standards help to manage the "looming" side wall problem
that has consistently been raised as a concern by neighbors. Packaging these tools at the right
calibration will most directly meet the goals and obiectives of the project.
Since March, staff has met internally to address the technical and regulatory issues related to
each tool. After developing some possible options for issues like measuring FAR and wall
height, staff convened a Technical Advisory Group to vet these options. The `1-echnical Advisory
Group consisted of eight members including architects, developers, builders, and a neighborhood
representative. This group met four times to provide feedback on construction related concerns
connected with P'AR, building coverage and wall articulation standards.
Attachment B: Calculating the Tools provides an overview of the tools selected, how they are
defined, and recommendations for how they would be measured. The suggestions made by the
Technical Advisory Group have either been incorporated into staff's recommendation where
appropriate or are specifically detailed for Planning Board's consideration.
NEXT STEPS:
Phase 3: Develop the Tools will conclude with the draft ordinance language being prepared by
Winter & Company. Phase 4: Implementation will begin at the June 18, 2009 Planning Board
meeting, which is the first public hearing in the adoption process. This process will continue
with Council's first reading of the ordinance tentatively scheduled for July 7 and the second
reading and public hearing on July 21, 2009. Following ordinance adoption, staff anticipates that
a period of time will be needed to implement the code changes including the development of a
brochure to explain the new regulations as well as new application forms.
Approved By:
Ruth McHeyser
Executive Director of Community Planning
ATTACHMENTS:
A. Project Area Map
B. Calculating the Tools
AGENDA ITEM 4 6A Page 2
ATTACHMENT A
Parcels and Zoning Districts in Analysis
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ATTACHMENT'S
Council Direction on Land Use Regulations:
Calculating the Tools
Floor Area Ratio (FAR):
A FAR standard would be used to relate overall building size to lot size. FAR is defined as the
ratio of the floor area of a building to the area of the lot on which the building is situated.
Y i
0.45 FAR or 3,120 SF \ 0.55 FAR or 3,850 SF
on a 7,000 SF lot on a 7,000 SF lot
Associated Definitions
Floor Area
The Boulder Revised Code defines floor area as the total square footage of all levels
measured to the outside surface of the exterior framing, or to the outside surface of the
exterior walls if there is no exterior framing, of a building or portion thereof, which
includes stairways, elevators, the portions of all exterior elevated above grade corridors,
balconies, and walkways that are required for primary or secondary egress by chapter 10-
5, "Building Code," B.R.C. 1981, storage and mechanical rooms, whether internal or
external to the structure, but excluding an atrium on the interior of a building where no
floor exists, a courtyard, the stairway opening at the uppermost floor of a building, and
floor area that meets the definition of uninhabitable space.
Uninhabitable Space
Uninhabitable space means a room that is six feet or less in floor to ceiling height, or a
room solely used to house mechanical or electrical equipment that serves the building,
including, without limitation, heating, cooling, electrical, ventilation and filtration
systems, or any parking facility located completely below grade on all sides of the
structure regardless of the topography of the site.
Basement
Basement means that portion of a building that is partially or totally below grade such
that no portion of the space extends more than two feet above the natural grade around
the perimeter of the building.
Diagram used to
describe basements
within the Boulder
Revised Code.
_ r Max
Story
Story means that portion of a building included between the surface of any floor and the
surface of the next floor above it, or if there is no floor above it, then between the floor
and the ceiling above it. A basement is a story if any portion of the space included
between the surface of the floor and the surface of the ceiling above it extends more than
two feet above the natural grade around the perimeter.
Sliding Scale by Lot Size and Zone District
Council provided direction supporting a FAR standard that relates building size to lot size
through a sliding scale approach and requested continued analysis of both the following
standards:
1. Winter & Company's recommendation of 0.45 FAR as a base lime standard on a 7,000
square foot lot for the RR-1, RR-2, RE, RL-1 and RL-2 districts. Lots less than 6,000
square feet will be limited by a FAR of 0.50 or a house size of 2,400 square feet,
whichever is greater.
The RL-2 zone will utilize the same maximum FAR standards as the RL-1 district.
However, because of the 6,000 square foot open space requirement in RL-2, only lots
8,000 square feet and above will be subject to a FAR limit.
A base line standard of 0.55 FAR on a 7,000 square foot lot for the RMX-1 zone. Lots
below 4,000 square feet would have a FAR of 0.73 or a house size of 2,400 square feet,
whichever is greater.
2. Planning Board's recommendation of a base line standard of 0.55 FAR on a 7,000 square
foot lot.
Calculating FAR
Determine the total floor area of the structure based on the definition in the Boulder Revised
Code which measures floor area as the total square footage of all levels measured to the outside
surface of the exterior walls and divided by the total square-footage of the lot.
FAR Example:
/ Lot size = 7,000 square feet
0 U First floor = 2,000 square feet
0 Second floor = 1,150 square feet
n a Q = Basement = not counted in FAR as this level
O - _ meets the definition of basement per code.
` Total Floor Area = 3,000 square feet
Floor Area Ratio (3,000 / 7,000) = 0.45
Measuring Floor Area for Partially Exposed Lower Levels
A partially exposed lower level is a story of a home that does not meet the definition of basement
as defined in the Boulder Revised Code. Currently, the square footage of a partially exposed
lower level included in FAR is calculated at either 50 or 100 percent depending on how much of
the perimeter wall is exposed.
Council's direction was to calculate this square footage at a more proportional measurement with
the exemption for calculating FAR at 36 inches.
The recommendation is to measure floor area for partially exposed lower levels in the same
manner as it is today without the requirement of categorizing floor area into 50 or 100 percent
increments. Instead, the amount of floor area included in FAR would be the exact percentage of
the exposed wall, based on linear feet exposed.
Staff is continuing to evaluate the exemption of 24 or 36 inches. Maintaining the 24 inch
standard allows for some consistency in the code between partially exposed lower levels and
basements. However, since the exemption relates to the amount of floor area calculated in FAR
and not whether the story is a basement or a partially exposed lower level, 36 inches could be
utilized.
Making use of an exact percentage of perimeter walls does not take into account construction
realities and the need for some flexibility with measuring finished grade. The Technical
Advisory Group suggested that a regulation that allows for + or - 6 inches in final grade for field
tolerance be developed.
Measuring from finished grade was determined the best solution for FAR calculations. Finished
grade will be what the neighbor experiences once construction is complete. However, measuring
FAR from finished grade will require applicants to provide a finished grading plan, which is not
generally required under the current permitting process.
Graphic depicting the linear
feet of one side of a structure
that would be used to
deternune the percentage of
the partially exposed lower
level included in FAR.
107
106 Exemption 36"
105
104 -
103 - r Lincnr ft. ccuntcd in FAR
102 - Fw clKd
i 101 - - - s
Measurement for FAR
Lot Line
36" Exemption
Ord, Ito 0 --~ga#
The following examples demonstrate the floor area of the partially exposed lower level that
would be counted in FAR if a 24 or 36 inch exemption was utilized:
Example: 24 inch exemption
Lot Size: 6,250 (50x125)
FAR: 0.44
- Partially Exposed Lower Level: 1,575
square feet
First Floor: 1,575 square feet
Second Floor: 0
Portion of Perimeter Exposed in Linear
Iy` 'I Feet = 75.6%
I; - Portion of Partially Exposed Lower
f M - Level counted in FAR (1,575 x 75.6° _
1,190 square feet
j Total Floor Area counted in FAR: 2,765
(.44 FAR)
*based on sliding scale at 0.45 on a 7,000 square
foot lot, this house could have an additional 225
Example: 36 inch exemption
Lot Size: 6,250 (50x 125)
FAR: 0.43
- - - Partially Exposed Lower Level: 1,575
t~Ii'-- - - square feet
- - - r First Floor: 1,575 square feet
Second Floor: 0
Portion of Perimeter Exposed in Linear
Feet = 71 %
Portion of Partially Exposed Lower
Level counted in FAR (1,5 7 5 x 71 _
yet 1,118 square feet
Total Floor Area counted in FAR: 2,693
(.43 FAR)
*based on sliding scale at 0.45 on a 7,000 square
foot lot. this house could have an additional 297
Exemptions will need to be written into the code for items like window wells that allow partially
exposed lower levels to have more livable space. However, tight parameters to prohibit extensive
manipulation of finished grade changes that technically expose the lower level as a third story
will be included.
l Item (C" _rtT;~e
Virtual Floor
C'ouncil's direction was to include regulations for virtual floors with a multiplier above a 10 foot
ceiling height. A virtual floor is a tool used to address impacts of high ceilings on overall
building mass which can not be captured by FAR. Virtual floors can be a very complex concept
to regulate, particularly in hones with varying roof heights or multifaceted internal ceiling
structures. Staff is continuing to work with Winter & Company and Code Studios to draft code
language that will be easy to regulate and demonstrate on building plans.
Graphic'depiction of a
virtual floor in a high
volume space.
/ Actual Floor
1
Jam` Virtual Floor
BuildinI4 Coverage:
A building coverage standard would be used to help preserve rear yard open space and reduce
privacy impacts on adjoining properties. The Boulder Revised Code defines building coverage as
the maximum horizontal area within the outer perimeter of the building walls, dividers, or
columns at ground level or above, whichever is the greater area. This includes, without
limitation, courts and exterior stairways, but excludes:
(1) Uncovered decks, porches, patios, terraces, and stairways all less than thirty inches high.
(2) The outer four feet of completely open, uncovered, cantilevered balconies that have a
minimum of eight feet vertical clearance below.
Sliding Scale by Lot Size and Zone District
Council provided direction supporting a building coverage standard as a maximum percentage of
lot size through a sliding scale approach, with continued analysis of the following two options:
1. Winter & Company's recommendation of 30 percent building coverage on a 7,000 square
foot lot as a base line standard for the RR-1, RR-2, RE, RL-1 and RL-2 districts. For lots
below 6,000 square feet in the RR-1, RR-2, RE, and RL-1 districts, building coverage is
35 percent.
The RL-2 zone will utilize the same maximum building coverage standards as the RL-1
district. However, because of the 6,000 square foot open space requirement in RL-2,
building coverage would apply only to lots 8,000 square feet and above.
For the RMX-1 distinct, a 35 percent building coverage on a 7,000 square foot lot is
recommended. In the RMX-1 district, lots below 4,000 square feet have a building
coverage of 50 percent.
2. Planning Board's recommendation of 35 percent building coverage as a base line
standard on a 7,000 square foot lot for a two-story home and 40 percent for a one-story
structure. To obtain the 40 percent building coverage, all structures on the lot would
have to maintain a one story configuration. In addition, Planning Board's
recommendation included a building coverage maximum of 20 percent for the second
story of the home.
Ap aY r6_k- Page#__ I
Overall -
Building ® O
2nd Floor Coverage
71 ~
Building
Coverage '
30% coverage or 2,100
square foot building
footprint on a 7,000 SF lot
t.
35% coverage or 2,450 40% coverage or 2,800
square foot building square foot building
footprint on a 7,000 SF lot footprint on a 7,000 SF lot
Calculating Building Coverage
Based on the definition for building coverage as defined in the Boulder Revised Code, divide the
total horizontal area of any structure on the lot by the total square footage of the lot.
Building Coverage Example:
Lot Size = 6,000 square feet
F Accessory Structure Area Covered by Principal = 1,300 square feet
Area Covered by Accessory = 500 square feet
Total Area Covered: 1,800 square feet
Lot Coverage (1,800 / 6,000) = 30%
- T
Principal Structure
Aida (gym #7 i }'age g - -
Calculating 2nd Story Building Coverage
If a second story building coverage is approved it would be calculated using the saine definition
and method as first floor building coverage. For those structures that are configured in such a
way that a traditional second story has not been developed but there is floor area above what
would be considered a traditional first story, that portion of the building will be measured as
second story building coverage. A regulation may be similar to the following:
Any floor area with a finished floor- height greater than 9 feet and less than 16 feet above
first finishedlloor height shall be considered as a second floor area for purposes of
calculating second floor building coverage.
For example, a tri-level or a hoarse with a loft would measure that area of the structure above 9
feet in height as a second story for the purposes of determining the second story building
coverage.
[Vuhh id 6A =pap#
Wall Articulation:
Wall height and length standards will help mitigate looming walls and privacy impacts on
adjacent properties by limiting wall dimensions near the side setback.
Bulk Plane and Wall Sculpting
Winter & Company proposed a wall sculpting standard to address looming walls along side
yards. Planning Board included an additional suggestion of a bulk plane standard. Council's
direction was to review both:
1. A bulk plane from the property line which would equate to two feet of wall height for
every one foot of setback; and
2. A maximum wall height at the minimum side setbacks of 20 feet with the maximum
height through a bulk plane standard of 1 foot of height for each foot from the side
setback. Within 5 feet of the minimum side setback, a maximum wall length standard of
35 feet would apply to any walls between 12 feet in height and the maximum allowed
wall height. At the maximum wall length, the wall height limit would be reduced to 12
feet or a minimum 5 foot wall offset towards the interior of the lot would be required.
During discussions with the Technical Advisory Group, an additional suggestion was made to
manage looming walls that somewhat unites the two recommendations. Their proposal is as
follows:
Utilize a bulkplane from the property line (instead offrom the side yard setbacks) and
incorporate the wall length articulation standards suggested by Winter & Company.
A bulk plane standard from the property line was considered more appropriate because setbacks
can vary between lots and in many cases can be non-standard on a lot. Property lines are a fixed
point to measure from and more generally follow natural grade contours. In addition, the
original recommendation of a 35 foot wall length with a 5 foot offset was considered more
difficult to develop from a construction standpoint and that even measurements would be more
efficient. Therefore, a 36 foot wall length with a 4 foot offset was suggested.
Two separate bulk plane standards were discussed. Both begin with a height of 12 feet at the
property line. Twelve feet was chosen as it mirrors the solar fence height at the property line for
the RL-1 district and emulates a standard already understood and utilized by the development
community and staff. Beginning at a height of 12 feet at the property line, one bulk plane has a
one for one height to setback ratio and the other has a two for one height to setback ratio.
Examples of all three wall articulation suggestions are shown below:
20 Foot Wall at Setback with Articulation Standards (Winter & Company
recommendation)
20':
35
Graphic example of a 5 foot
horizontal offset that
articulates side wall mass.
35' 20'
Graphic example of a
t ` vertical reduction to one-
story that reduces side wall
mass.
Pagai
2 for 1 Bulk Plane at the Property Line (Recommended by Planning Board)
20-
2
501
Graphic example of two feet in
height for every one foot of
setback on a 50 foot wide lot.
r35'
Graphic example of two feet in
height for every one foot of
setback on a 70 foot wide lot.
~ : RPM - 61, -Page F-4.~
Bulk Plane from Setback (One of the Technical Advisory Group suggestions)
r"
35' i
ta'
i
r; rrr r '~1d"*~~~
Graphic example of a bulk
plane with 12 feet of height at
the property line and then one
foot of height for every one
foot of setback on a 50 foot
wide lot.
35'
22'
SIC--' ~
Graphic example of a bulk
plane with 12 feet of height at
y the property line and then one
foot of height for every one
:1r foot of setback on a 70 foot
wide lot.
Exemptions for Architectural Details
There was a concern from the Technical Advisory Group that the use of a bulk plane coupled
with the requirements of the solar ordinance would begin to force a specific structural form and
that single-family construction may become monotonous as development tried to build within
these constraints. The Group suggested that if a bulk plane from the property line is ultimately
approved than there should be some flexibility for things like dormers and trellises. These types
of architectural details should be allowed to penetrate the bulk plane as long as an equal amount
of space along that same wall was subtracted from the structure. This might be a circumstance
best review and approved through an administrative residential site plan review process.
Wall Length
Wall length will be measured for those walls located within the side yard. Wall length will be
expressed as the continuous length of building wall without at least a four foot horizontal offset
or a height reduction to a one-story configuration (12 feet or less).
Perceived wall
length reduced by
horizontal offset.
r'
n;ntla Item If page #
i
Visible Wall Height
Wall height will be measured for those portions of the building that are located within the side
yard. The height of the visible wall will be described as the full length of the vertical wall from
finished grade to the top of the roof structure. If no roof structure exists, wall height will be the
full visible length of the vertical wall measured from finished grade.
i
Height will be measured from
finished grade to the top of the
roof structure.
Visible Wall Height
The Technical Advisory Group discussed the construction details of what should be considered
in the height of a two-story single-family structure. It was suggested that height should include
the following details and measurements:
• Foundation: 6 inches is required by building code but actual developments typically need
1 to 2 feet.
• First Level Floor Structure: 10 to 12 inches
• First Level Floor to Ceiling Height: 8 to 9 feet
• Second Level Floor Structure: 10 to 12 inches
• Second Level Floor to Ceiling Height: 8 feet
• Roof Structure: 3 to 4 feet (to meet insulation energy code requirements)
• Total Height: 22 to 25 feet
As suggested by the Technical Advisory Group, we are recommending that the visible wall
length be measured to the top of the roof structure from finished grade. As with FAR, measuring
visible walls from finished grade was determined the best solution. Finished grade will be what
the neighbor experiences once construction is complete.
A." ham
Measuring to the top of a roof structure instead of where the wall meets the roof is to
accommodate the variety of roof systems that can be built. For example, the wall height to a roof
with an eave may be taller than the wall height to a roof with an cave and soffit. However,
because of this suggested change in how wall height is measured an increase in height may be
warranted. The Technical Advisory Group indicated that if council's final decision was to allow
two-story elements at the minimum side yard setback, a height of 20 feet may not accommodate
two full stories and proper drainage at the foundation.
Side Wall Adjacency Issue
For side walls that abut a multi-family or nonresidential development, side wall articulation will
not be required.
2°d Story Rear Yard Setback:
Another recommendation made by Planning Board to address looming walls was to limit two-
story structures through a rear yard setback. Staff completed some analysis of a rear yard
setback based on the depth of lots. We began with a setback for the rear 3rd of the lot. This was
effective for lots that had a depth no longer than 100 feet, which essentially limited 2"d stories to
approximately 41 feet in length. At that point, the rear yard setback would need to increase to
the rear half of the lot. Ultimately, the depth of the lot plays significantly into whether the
setback is either too restrictive, works effectively, or is not restrictive enough.
An additional consideration regarding rear yard setbacks is the placement of the 2"d story on the
lot. In many instances, the original one-story construction of the house is maintained and the rear
addition is developed with two stories. The rear yard setback restriction would need to be
calibrated to allow this configuration. Finding the balance between restricting looming walls and
allowing for variety of 2"d story developments may be difficult on varying lot depths.
NOTE: The remainder of this document is for informational purposes ofriy and will not be
included in the Technical Study Session. However, staff wanted to inform Planning Board of the
work that has been completed on a review process for single-family development and the
additional issues raised by Planning Board during the February 26 meeting.
Administrative Residential Site Flan ]review Process
Under the original recommendation made by Winter & Company and staff, a two-tiered process
for development approvals was suggested. The first tier was the standard building permit
process which is in use by the city today; with the only difference being the additional
regulations the applicant will be required to meet. The second tier was a staff level design
review process to address the issue of flexibility. We have heard from the professional design
community and from homeowners that they need an avenue to do something outside of the soon
to be established regulations without requiring a variance from BOZA. The recommendation
was to allow projects to exceed the standards by up to 20 percent if they could comply with a
specified set of review criteria.
During the public hearings held in February and March, Planning Board and Council indicated
that they had some concerns regarding a design review process and the 20 percent flexibility
exceptions. The direction received from Council was that in most instances, variances to the
standards should be based on a hardship. However, there was still some discussion about
allowing some minor modifications based on focused circumstances, particularly on those lots
where the new regulations make their existing conditions non-standard.
Staff is continuing to work internally and with Winter & Company to draft a process that would
meet the intent of council's direction. The difficulty is finding the balance between what
circumstances would be considered a hardship and should be reviewed by the Board of Zoning
Adjustment and what focused circumstances would be allowed some administrative approval.
We are considering an administrative residential site plan review process that spells out specific
eligibility requirements that would mitigate the number of qualified applicants, as well as limited
modification allowances. Also, we are still evaluating the possibility of utilizing the Landmarks
Board as the reviewing body for projects within the historic districts and that are individually
landmarked. These projects are currently required to go through the landmark alteration
certificate review process. By utilizing this approach we can eliminate the need for two separate
reviews.
Additional Issues Raised by Planning Board and Directed by Council:
Accessory Structures
1. Distance Requirements: At a "face to face" development where the accessory structure
wall faces a primary structure wall on the same lot the following distances are
recommended:
15 feet for a two-story accessory to a two-story primary structure
• 10 feet for a two-story (primary or accessory) to one-story (primary or accessory)
structure
• 6 feet between one-story structures with a maximum 6 inch eave overhang
Staff to review if small structures (less than 100 square feet) can be exempt from
these requirements.
2. Setbacks from Property Line: At the zero setback, accessory structures are prohibited
from developing a second story.
3. Second-Story Square Footage: Limit the second floor to 500 square feet.
4. Accessory Structure Building Coverage Limit: Council requested staff review a building
coverage limit for accessory structures. Currently, the only limit on size of accessory
structures is that they must be smaller than the primary building on the lot. Through our
research, we have found that many communities have a square footage limit for detached
accessory buildings. Others use a percentage of the primary structure. With the inclusion
of accessory structure in the total FAR calculation for the lot, it is likely that the size of
detached accessory structures will be limited to utilize that square footage in the primary
building. With this in mind, we would recommend a building coverage limit for detached
accessory buildings of 50 percent of the building coverage for the primary structure. On
a 7,000 square foot lot under the staff recommendation of 30 percent building coverage
this would equate to an accessory building footprint of 1,050 square feet. Under the
Planning Board's recommendation of 35 percent building coverage would equate to a
1,225 building footprint for accessory structures.
Tree Planting Program
Currently, in the single-family zoning districts only street trees are required by the Boulder
Revised Code. The standard is one tree for every 40 linear feet. When a building permit
application is submitted for a remodel, addition, or new home a review to ensure street trees have
been included is completed if the redevelopment value is more than 25 percent of the Boulder
County Assessor's actual value of the existing structure. In 2008, approximately 338 landscape
inspections were completed on detached single-family developments.
To address Council's direction on developing a tree planting program, a new regulation for
additional trees within the lot could be developed. For ease of administration, the new
requirements could be tied to the threshold standard of redevelopment value that is currently in
the code. For example:
New single-family residential development and redevelopment involving expansion of the
total building floor area which exceeds twenty-five percent of the Boulder County
Assessor's actual value of the existing structure shall require compliance with the street
and alley tree requirements, the on-site tree requirements, and the trash and parking
screening requirements.
n
For every 500 square feet of new residential construction, including additions to existing
homes, one medium or large maturing deciduous tree at least two-inches in caliper
measured six inches above the ground or one small maturing tree at least one and one-
half inch in caliper measured six inches above the ground as identified on the approved
street tree list in section 3.03-1, City of Boulder Design and Construction Standards shall
he required on-site.
Utilizing the existing threshold standard would not increase the number of permits that are
reviewed for landscaping materials. It would however increase the time required by the reviewer
to ensure that all of the landscaping requirements are being met, both during the permit review
and at inspection. The Landscape Architect position responsible to do this review is a fix-term
position through 2009. At this time, it is not expected to be renewed due to budgetary
constraints.
Garages
To continue to address the public realm, the Board recommended and City Council confirmed
that staff should study garage numbers, location, presentations, entry emphasis, offsets, etc. Due
to project time constraints, this item may need to be resolved at the conclusion of the public
hearings on the FAR, building coverage, and wall articulation tools.
Neighbor Notification
Council directed staff to review a requirement that a courtesy notice be sent to adjacent
neighbors (and across streets and alleys) once a building pernzit has been issued. This is a fairly
simple request to achieve. A list of neighboring property addresses could be generated at the
issuance of a building pen-nit and,a fonn letter processed and mailed to these addresses. Since
building permits are a total cost recovery permit through the city, the cost to issue these notices
would have to be included in the building permit fees. We are working to determine the cost for
this service.