Transcript Slide 1

Height Recommendations
September 25, 2008
Zoning Commission Case No. 08-06-01
The District of Columbia Office of Planning’s
Comprehensive Review of Zoning Regulations
DC Zoning Review
September 25, 2008
1
Height Regulation Background
• 1910 Height Act
– Height measured by width of street
• District Zoning Regulations:
– Height measured by zone
– May be more restrictive than Height Act
• Both documents are interpreted by the Zoning
Administrator
DC Zoning Review
September 25, 2008
2
Height Topic Area Review Process
• Working Group
• Taskforce
• Public Review
• Zoning Commission
DC Zoning Review
September 25, 2008
3
GOALS OF HEIGHT REGULATION
PROPOSALS
• Make Consideration of Height in Zoning Regulations Clearer
and More Predictable
• Acknowledge Ambiguities in Regulation of Height
• Resolve Potential Differences by Balancing:
– Previous Interpretations and Precedent
– National Symbolism of Skyline and Tradition of
Horizontality
– Physical Factors
– Sustainability Considerations
– Impact on Development Potential
DC Zoning Review
September 25, 2008
4
MAJOR TOPICS CONSIDERED
1. Determining a Building’s Maximum
Permitted Height
2. Measuring a Building’s Height
3. Understanding the Types and Heights of
Structures Permitted Above a Roof
DC Zoning Review
September 25, 2008
5
TOPICS NOT CONSIDERED HERE
– Appropriate Heights for Particular Zones or
Locations
– Whether the Height Act Should be
Changed
DC Zoning Review
September 25, 2008
6
Ambiguities
Architectural Embellishments
Meaningful Connection
Building Definition
Measuring Point
Business Street
Natural Grade
Federal Reservations or Open Space:
Buildings Confronting, and Streets
Interrupted
Residential Street
Exterior Walls
Roof Structures Permitted Above Height
Act Limits
Front/Frontage
DC Zoning Review
September 25, 2008
7
RECOMMENDATIONS
A.DETERMINING MAXIMUM PERMITTED HEIGHT
Rec. 1:
Rec. 2:
Rec. 3:
Rec. 4:
Streets with multiple frontages
Streets fronting on open space
Business vs. Residence streets
Single vs. Multiple Buildings
B. MEASURING A BUILDING’S HEIGHT
Rec. 5:
Rec. 6:
Rec. 7:
Rec. 8:
Location of Bottom Measuring Point
Elevation of Bottom Measuring Point
Natural Grade
Top Measuring Point
C. STRUCTURES ABOVE A ROOF
Rec. 9: Structures Permitted Atop a Roof
Rec. 10: Height, Width, Massing
Rec. 11: Roof Structure Setbacks
Rec. 12: Exterior Walls
DC Zoning Review
September 25, 2008
8
Rec. 1:Frontage on Multiple Streets
• Any street abutting a building’s property line may be
used to determine the maximum height.
• There should be no requirement for the presence of an
door or entrance.
• Consistent with current practice. Clarifies that a building may draw
height from any side regardless of the presence of a door.
A. DETERMINING MAXIMUM PERMITTED HEIGHT
9
Rec. 2: Buildings Confronting Federal
Reservations or Open Space
Clarify what R-O-W may be used to determine height
May use “A”, “B”, “C” or “D” but not “E” or “F”
May not add two R-O-W or include reservation
A. DETERMINING MAXIMUM PERMITTED HEIGHT
10
Rec. 2: Potentially Affected Federal
Reservations or Open Space
A. DETERMINING MAXIMUM PERMITTED HEIGHT
11
Rec. 3: Residence & Business Streets
• A “Residence street” would be
a) any block face that contains any residential property
located in a low to moderate density zone district; or
b) any block face entirely made up of properties of any
existing residential zone.
• A “Business street” would mean any other block face.
As with Recommendation 1, a property adjacent to both a commercial and a
residence street could choose its frontage.
A. DETERMINING MAXIMUM PERMITTED HEIGHT
12
Rec. 3: Residence & Business Streets
RESIDENTIAL
C2-A
BUSINESS
R4
BUSINESS
RESIDENTIAL
C2-A
R4
RESIDENTIAL
RESIDENTIAL
R5-E
C2-A
BUSINESS
RESIDENTIAL
RESIDENTIAL
BUSINESS
RESIDENTIAL
C2-A
R-5-E
R4
C2-A
BUSINESS
A. DETERMINING MAXIMUM PERMITTED HEIGHT
13
Rec. 4: Single Building or Multiple
Buildings?
Potential additional
height due to minor
building ni terconnection
Height as permit ted
relative to Narrower Street “B”
Minor building
interconnection
Height as permit ted
relative to Wider Street “A”
Flat grade to site
Narrower
Street “B”
Development Site Abutting Multiple St
reets
Wider
Street “A”
A. DETERMINING MAXIMUM PERMITTED HEIGHT
14
Rec. 4: Single Building or Multiple
Buildings?
• Existing regulations:
– do not recognize connections below ground
– imply connections must be above ground
– provide no definition of above ground connection
• There is little consistency in existing practice
• Applicant burdened with proving undefined “meaningful
connection”
A. DETERMINING MAXIMUM PERMITTED HEIGHT
15
Rec. 4: Single Building or Multiple
Buildings?
OP Recommends:
• Distinction between single & multiple buildings
needs to be clarified
• To be considered single, a building must have
a.
The presence of an enclosed connection that permits passage by
building users on at least one floor
And/or
b.
Common usable space accessible by all occupants of the building
A. DETERMINING MAXIMUM PERMITTED HEIGHT
16
Rec. 5: Location of Bottom Measuring
Point
Clarify the location of the measuring point for building height when a building
faces more than one street.
Potential for taller building
on Narrower Street
Height as permitted
relative to Wider Street “A”
Allowable Height if
based uponstreet chosento
ht
determine heig
Height as permitted
relative to Wider Street “A”
Sloped grade to site
Narrower and higher
Street “B” selected
to measure
applicable height
St
Development Site Abutting Multiple reets
B. MEASURING A BUILDING’S HEIGHT
l Street “A”
Wider andower
selected to determine
allowable height
17
Rec. 5: Bottom Measuring Point
Option 1: The street chosen to determine the maximum
allowable height must also be used to determine the
point from which building height is measured.
– New approach that ensures that height on at least one
frontage is based on street width
– Could decrease amount of square footage developable on
through block sites with significant elevation changes
– Potentially makes dozens of downtown buildings nonconforming
B. MEASURING A BUILDING’S HEIGHT
18
Rec. 5: Bottom Measuring Point
Option 2: Any abutting street may be used to determine
the measuring point regardless of which street is used
to determine maximum allowable height.
– Follows over 50 years of precedent
– Would not affect existing or planned projects
– Preserves existing development potential within the
Height Act
B. MEASURING A BUILDING’S HEIGHT
19
Rec. 6: Elevation of Bottom
Measuring Point
OP Recommends:
– Measure from the front of the building based on
the elevation of the curb plus a slope for
drainage.
• Height Act says sidewalk
Proposed
• Zoning Regulations say curb
Existing
Street
Curb
B. MEASURING A BUILDING’S HEIGHT
Sidewalk
Building
20
Rec. 7: Natural Grade
• Clarify definition of natural grade and measuring point for
elevated or depressed areas
• Natural grade is the ground elevation prior to issuance of
first permit needed for new building construction.
• Where street frontage is affected by an artificial elevation,
height is measured from the logical continuation of the
surrounding street grid
B. MEASURING A BUILDING’S HEIGHT
21
Rec. 8: Top Measuring Point
• Buildings shall be measured to the top of the roof including
any parapet on exterior walls, or any other continuation of
the exterior walls.
• Buildings below the Height Act may add a 4’ parapet
Max. Heig ht Under Heig ht Act
4 Ft.
Top of Roof
No Parapet
With Parapet
B. MEASURING A BUILDING’S HEIGHT
22
Rec. 9: Structures Permitted Atop
a Roof
Organize and modernize the list of structures allowed on the
roof.
•
Ornamental features limited to spires, towers, domes, pinnacles, and minarets,
that are aesthetic, primarily vertical elements of a building, even if used to
cover/hide/mask utilitarian or amenity features;
C. STRUCTURES ABOVE A ROOF
23
Rec. 9: Structures Permitted Atop
a Roof
Organize and modernize the list of structures allowed on the
roof.
•
Utilitarian features including, but not limited to, mechanical equipment, safety
railings, stairwell access, elevator penthouses, and building components or
appurtenances dedicated to the environmental sustainability of the building; and
Utilitarian
Ornamental
Utilitarian
C. STRUCTURES ABOVE A ROOF
24
Rec. 9: Structures Permitted Atop
a Roof
Organize and modernize the list of structures allowed on the
roof.
•
Amenity features such as structures accessory to communal outdoor recreation
space, communal pergolas, communal enclosed recreation space, and structures
limited to providing individual unit access to private, unenclosed space atop a
roof.
C. STRUCTURES ABOVE A ROOF
25
Rec. 10: Height, Width and Massing of
Structures Atop a Roof
• Remove roof structures from FAR calculation and allowed to occupy up to
40% of roof area
• Remove uniform height & single enclosure requirements
• Utilitarian and amenity features may not rise more than 20’ above the
roof
• Ornamental features:
– 30’ limit
– may contain utilitarian or amenity features
• Special Exception relief allowed for all of these requirements
C. STRUCTURES ABOVE A ROOF
26
Rec. 11: Setbacks for Structures Atop
a Roof
• Utilitarian and amenity features shall be set back 1 to 1
from:
(a) exterior wall (Rec. 12);
(b) wall set back from and facing a side lot line;
(c) lot line wall when taller than adjacent building
Special Exception relief allowed for these requirements
Additional Study is needed for setbacks atop rowhouses and single family
homes
C. STRUCTURES ABOVE A ROOF
27
Rec. 11: Setbacks Atop a Roof
A
Setback Required
Exterior Wall
No S etback R equired
Exterior Wall
E xterior Wall
E xterior Wall
B
C. STRUCTURES ABOVE A ROOF
S ide Lot Line
C
28
Rec. 12: Exterior Walls
An exterior wall is any wall facing a public street or alley
• Decades of precedent have not considered alley facing walls
to be exterior walls.
• Recommendation would not consider party walls or other
side walls to be exterior walls
• BZA would not be able to grant setback relief from exterior
walls above level of Height Act.
C. STRUCTURES ABOVE A ROOF
29
Next Steps
• Public Comments
• Guidance from Zoning Commission
• Drafting Proposed Zoning Text
• Further Public Comment & Commission
Consideration
DC Zoning Review
September 25, 2008
30