HomeMy WebLinkAboutPlanning 2018-05-24 Item 4 - Tukwila South Overlay Residential Development Standards and Guidelines - Attachment C: Multi-Family Design ManualATTACHMENT C
MULTI -FAMILY DESIGN GUIDELINES
10/13/92
John W. Rants, Mayor
Tukwila City Council
Allan Ekberg, President
Joe Duffie
Joan Hernandez
Steve Lawrence
Steve Mullet
Dennis Robertson
Charles Simpson
Tukwila Planning Commission
George Malina, Chairperson
Scott Clark
Jack Flesher
George Gomez
Jim Haggerton
Gerald Knudsen
Vern Meryhew
Private Development Advisory
Focus Group
Colin Quinn, Lincoln Properties
Carl Bloss, Schneider Homes
Everett Foster, Rosewood Co.
Randy Brealey, Developer
Joe Alhadeff, Meridian Mortgage
Jim Potter, Seattle -King County Master
Builders Assoc.
Tukwila Principal Staff Members
L. Rick Beeler, Director
Jack P. Pace, Senior Planner
Vernon Umetsu, Project Planner
Stacia Norris, Document Processing
Chris Collins, Word Processing
Sharon Dibble, Graphics
Consultants
William Kreager, Mithun Group
Architects
Tom Rengstorf, Rengstorf and
Associates Landscape Architects
Michael Aipersbach, Aipersbach &
Ryan Planners
14
TABLE OF CONTENTS
INTRODUCTION
SITE PLANNING
Streetscape -. The transition from public to private spaces
Site Design Quality
Natural Environmental Considerations
Circulation
Parking
Entrance Areas
Energy Conservation
Crime Prevention
Signs/Graphics
II BUILDING DESIGN
Relationship to Adjoining Site
Building Design
Exterior Elevations
III LANDSCAPE/SITE TREATMENT
Landscape Design
Protection of Existing Trees
Screening
Buffering
Usable Outdoor Space
Recreation Area Design
IV MISCELLANEOUS STRUCTURES/STREET FURNITURE
Lighting
Fencing, Walls and Screening
Street Furniture
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20
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LIST OF FIGURES
FIGURE
NO. TITLE PAGE
1 Summary Guideline Process. 1
2 Project siting, architecture and landscaping provide a sense 2
of high quality design from road to interior spaces, design
harmony between projects, and complement desirable
neighborhood elements.
3 Street trees and one story pitched roof buildings are used to
help enclose the pedestrian streetscape without dominating it.
4 Buildings and landscaping are sited to reduce the prominence 4
of large paved areas.
5 Parking is located to the side of the project to minimize an 4
auto dominated streetscape.
6 Site buildings to group open space in significant areas, retain 5
mature trees, and create opportunities for residents to meet
and recreate.
7 Significant trees are retained through building siting and use
of required interior parking lot landscaping.
8 The topographical representation below shows radical water
flow, foliage placement in swales, and lots that conform with
the landform configuration. The shaded area is a concrete
terrace drain required by building codes. The sketch contrasts
site planning for conventionally graded and landform graded
slopes.
9 Creative site planning can turn a drainage problem into an an 6
open space amenity.
10 Key sidewalk intersections and segments are marked with 7
contrasting pavers.
11 Detached garages and cul de sacs reduce parking area 7
prominence on the streetscape.
12 Site design incorporates scattered, less dominating parking
areas.
6
13 A site plan with four parking areas, an access road and
parking circulation aisles.
14 Interior and perimeter landscaping reduce the visual affects
of large paved parking areas. Interior landscaping should be
increased as parking lots get larger.
9
LIST OF FIGURES
FIGURE
NO. TITLE PAGE
15 Tandem parking spaces should only be used in conjunction 10
with under structure parking.
16 Project entry provides an immediate sense of high quality 10
design.
17 A high quality pedestrian entry is given equal weight with auto 11
entries.
18 Outdoor oriented recreation areas maximize solar exposure. 12
19 Site planning should create varying degrees of privacy. 12
20 Cul de sacs create semi -private "courts" to provide increased 13
security and informal play areas.
21 Semi -private project areas are separated from general public 13
areas using transitional spaces which are visually open in
design.
22 A transition from semi -private to private spaces with low 14
volume paths, trellises and alcoves.
23 Multi -family building line and proportions are harmonious 15
with surrounding single family dwellings.
24 Multi -family building shape, height and length are similar to 15
adjacent single family buildings.
25 No particular architectural design is specified. However, the 16
sum of a structures shape, fenestration, fine detailing and
colors should be superior architectural design which is
harmonious with the neighborhood.
26 Minimum building separation. 17
27 Design details need not be costly to significantly improve 18
architectural quality.
28 Offsets, changes in materials, and other fine detailing are used 19
to provide architectural interest.
29 Landscaping shown at 5 years after planting. 20
30 Live groundcover is planted to achieve 90% coverage within 3 20
years from installation.
31 Landscaping along street frontages should be high quality and 21
reflect three tiers of plants.
LIST OF FIGURES
FIGURE
NO. TITLE PAGE
32 Perimeter landscaping along the side and rear lot lines provide 21
year-round buffering and transition.
33 A typical shrub hedge separating use areas with standard nursery 22
stock.
34 Tree wells can help save hillside trees only to a depth of 4 feet. 24
35 Trees protected with a chain link fence at the drip line during 24
construction,
36 Separation of marginally compatible uses with only plants. 25
37 Separation of marginally compatible uses with fencing and 26
plants.
38 Full separation of incompatible uses with masonry wall and 26
plants.
39 Recreation area design for safety includes siting the children's 27
play lot in a central or easily observed area.
40 A recreation space for the 5-12 year old group which facilitates 28
group interaction and skill testing.
41 Maximum parking area light standard height is 20 feet or the 29
building height; whichever is less.
42 Maximum grounds lighting standard height is 15 feet. 29
43 Dumpsters are sited and screened to minimize prominence. 30
18
INTRODUCTION
Guideline Use
Fig. 1: SUMMARY DESIGN REVIEW PROCESS
Recognize that all projects must reflect high design
quality which are harmonious with the natural and
manmade environments (TMC 18.60.010).
Review required multi -family design criteria (TMC
18.60.053) for general requirements on project design
quality.
Review the illustrative Multi -family Design Guidelines
herein for specific design examples and orientations.
Project Architect reviews all criteria and guidelines then:
a. adapts the illustrative design concepts to the specific
site
or
b. develops an alternative design approach with results
in a similar level of design quality.
Planning staff reviews and works with Project Architect.
Tukwila Board of Architectural Review evaluates the
development and ensures that only well designed
projects which maintain neighborhood livability are
approved.
The City of Tukwila has adopted a policy that all multi-
family developments must reflect high design quality;
regardless of whether the project is oriented toward the
low, middle, or high cost housing market. This does not
mean that only high cost projects will be permitted in
Tukwila. However, it does mean that maintaining livable
neighborhoods requires architectural focus, design
symmetry, and neighborhood harmony in low cost housing
as well as high cost housing.
Tukwila's Zoning Code includes various development
standards to reflect basic minimum requirements such as
density, building setbacks, and parking. Board of
Architectural Review (BAR) approval is the basis for
ensuring high design quality (TMC 18.60).
BAR. approval does not focus on required "numbers" to
defme quality design. Instead, it relies on overall results as
generally defined in TMC 18.60.053.
This Design Manual is provided to help the applicant
understand the City's general desired level of quality, and
to provide the BAR with a further basis for determining the
needed level of design quality.
These design guidelines are not requirements nor are they a
substitute for competent work by design professionals on a
site specific basis. The City encourages innovative design
alternatives which better reflect site specific conditions and
opportunities. The City recognizes that there are many
techniques and architectural forms which can be used to
reflect a design quality equivalent to these guidelines.
In some cases such as high density projects on sensitive or
prominent sites, the design quality reflected in these
guidelines must be exceeded in order to maintain the
existing level of neighborhood livability.
When using these Design Guidelines to review senior
citizen housing developments the following items shall not
apply because they do not address the density, use or other
characteristics of senior housing:
1. Site Planning
Figure 3
Building Design
Items 2 and 6
111. Landscape/Site Treatment.
Figures 31 and 32
Items 30, 31, 32, 33 34, and 35
The remaining introductory section discusses a vision for
Tukwila's neighborhoods. This is followed by specific design
guidelines which have been grouped to generally reflect the
BAR review criteria (TMC 18.60) that they illustrate.
19
I. SITE PLANNING
Streetscape
The transition from public to private spaces
Fig. 2: Project siting, architecture and
landscaping provide a sense of high quality
design from road to interior spaces, design
harmony between projects, and complement
desirable neighborhood elements.
1. "The challenge facing builders in the 90's ... is to
develop pedestrian atmosphere reducingithe impact of
the automobile. Many developments in the last
twenty years have produced streetscapes often
dominated by garage doors and driveways creating an
environment with less neighborhood interaction: an
environment discouraging pedestrian activity."
("Development Digest"; Winter, 1990.)
2. A streetscape which is safe and reflects a high
quality coordinated design, is essential in multi-
family neighborhoods. This overlay of street front
design harmony is important to maintaining the sense
of "community" which can be lost in an environment
of diverse, sometimes sterile/mediocre project designs
and automobiles.
15 foot Landscape strip provides transition
from public streeucape to one-story project
rovide a be architecture.
' g lots.
2
20
I. SITE PLANNING
Fig. 3: Street trees and one story pitched roof
buildings are used to help enclose the pedestrian
streetscape without dominating it.
3. The public oriented elements of a well designed,
pedestrian streetscape include separated sidewalks;
coordinated placement and retention of large stature
trees; coordinated street furniture, signage, and
lighting; and integrated recreational facility links.
Curb -line sidewalks may be acceptable on cul-de-sacs
or local access loops with low traffic volumes (i.e.,
generated by 20 housing units)
4. The private site elements of a well designed
pedestrian streetscape include buildings which use
siting, scale, and materials to provide a sense of
quality design and enclosure without overwhelming
the pedestrian with building mass.
5. There should be a gradual, high quality transition
from a pedestrian oriented streetscape to multi -story
buildings. The transition should emphasize quality
pedestrian scale architecture and materials, plantings
of varying heights, and use pedestrian oriented
entries, courts, and lighting. It is at this interface that
the neighborhood's quality will be perceived by the
public.
3
I. SITE PLANNING
Site Design Quality
Fig. 4: Buildings and landscaping are sited to
reduce the prominence of large paved areas.
6. Site planning and building architecture must
provide a high quality project design. Landscaping
should not be needed to hide mediocre building
design, but further enhance an already good design,
and result in a high quality project.
7. Site design should be integrated with the
neighborhood. Project design integration should
include coordination of circulation, landscaping,
envy
a recreation spaces, and building location with the
surrounding area. A visual distinction using
landform, landscaping, or materials may separate a
project from the general neighborhood. However,
high "fortress" walls should be avoided and buildings
should not turn their backs to the street.
Central island visuahy breaks up lot with
landscaping and a (maitre as cars enter
theparldng area.
Fig. 5: Parking is located to the side of the
project to minimize an auto dominated
streetscape.
8. Walls, shrubs, and other visual obstructions
between street frontage and building architecture
should be limited to a maximum 3.5 ft. height to
allow easy surveillance by Police Department car
patrols. Higher fencing may be installed if it uses
visually open materials such as wrought iron bars and
3 inch spaced grape stake fences.
9. Minimize the prominence of street front parking
areas by using architecture and landscaping to break
up or screen these sterile asphalt pads, moving
parking to the side or rear, and breaking up large
parking areas into smaller (i.e., 20-40 space)
groupings. Vehicles should be treated as a means of
transportation; not emphasized as a prominent design
feature. (Fig. 11, 12, and 23)
4
22
I. SITE PLANNING
Natural Environment
Fig. 6: Site buildings to group open space in
significant areas, retain mature trees, and
create opportunities for residents to meet and
recreate.
P ' pen space
forms a dramatic
pedestrian envy, and
oriaued on the
project's open space
focal point.
4,1 space grouped into significant areas
which can have many uses.
Fig. 7: Significant trees are retained through
building siting and use of required interior
parking lot landscaping.
10. Minimize a project's visual prominence and
enhance the harmony with its natural setting. (Fig. 7)
11. Open space should be designed as a series of
connected, natural woods and formal garden areas,
each serving a precise functional and aesthetic
purpose. Diversity in organizing these spaces is
important since monotonous housing developments
are as often the result of repetitive spatial organization
as they are repetitive building masses.
12. One or more open space focal points should be
incorporated as a basic site planning element.
13. Building scale and materials should provide a
sense of human scale, enclosure and warmth in
defining these spaces. Small, isolated planters alone
are not adequate to break up paved areas and building
mass, separate structures, and define spaces.
14. Buildings should be located to maximize
significant tree retention on slopes, retain tree stands,
and minimize disturbing sensitive areas.
15. Retaining large stature trees and tree stands on
site, very significantly improves the integration of
new developments into Tukwila's mature
neighborhoods. Significant trees would include trees
with over a six inch diameter as measured five feet
above grade.
• 16. Every possible effort should be made to
incorporate existing natural vegetation into project
design. This should include, but not be limited to
moving buildings or reducing project densities to
preserve significant stands of mature trees. This
would not include preserving a higher percentage of
tree coverage than required in landscaping standards
(i.e., 40% horizontal tree coverage of all areas not
occupied by a building).
slope to retain
ees duce prominence.
I. SITE PLANNING
Fig. 8: The topographical representation below
shows radical water flow, foliage placement in
swales, and lots that conform with the landform
configuration. The shaded area is a concrete
terrace drain required by building codes. The
sketch contrasts site planning for conventionally
graded and landform graded slopes.
Building
Building
Building
Slope
STREET
Conventional Site Planning
Landform Site Planning
17. Site coverage on slopes should be minimized to
reduce visual impact. Site coverage limitations are
not as significant on flat sites where lower buildings
may be preferable to maximize architectural harmony
with nearby structures and the streetscape.
18. Landform grading should be used when feasible
to reflect the natural topography and retain mature
trees.
19. Creative design should be applied to tum natural
site "problems" into project amenities. (Fig. 9)
Fig. 9: Creative site planning can turn a
drainage problem into an open space amenity.
6
211
I. SITE PLANNING
Circulation
Fig. 10: Key sidewalk intersections and
segments are marked with contrasting pavers.
Building enby mea
Fig. 11: Detached garages and cul de sacs
reduce parking area prominence on the
streetscape.
20. The project entry should reflect a high level of
quality using distinctive materials, landscaping and
structures.
21. A comprehensive system of pedestrian sidewalks
should link all building entries, parking lots,
recreation areas and the project entries; with the area -
wide sidewalk system.
22. Sidewalks should be a minimum of six feet wide
between public roadway and the junction where
pedestrian traffic begins to disperse. This would
allow one pedestrian to pass another and remain on
the sidewalk. A minimum four foot wide sidewalk,
may then be acceptable.
23. Sidewalk crossings of on-site roadways should be
distinguished by a different material and slightly
raised to prevent runoff from flowing across them.
24. The on-site vehicle circulation system should be
designed as follows:
A maximum of two vehicle access points,
depending on parcel characteristics and difficulty
of access, to reduce traffic impacts and the site
area devoted to roads instead of architecture and
landscape/recreation space,
• Create very low volume cul-de-sacs to allow
multiple use as street oriented social/recreation
areas, and
• Stress shared driveways between adjacent
developments.
25. Driveways should avoid crossing pedestrian
walkways and paths from residence to children's play
area.
7
I. SITE PLANNING
Parking
Fig. 12: Site design incorporates scattered, less
dominating parking areas.
Fig. 13: A site plan with four parking areas, an access
road and parking circulation aisle.
26. The prominence of parking areas should be
minimized by building siting, under building and -
tandem parking, and interior perimeter landscaping.
Parking areas should not dominatethe buildings they
are intended to serve.
27. Parking areas should be located within 200 feet of
the farthest dwelling unit for the convenience of
residents. It is also desirable in many instances to use
several smaller parking areas rather than a few large
lots.
28. The optimum design for a parking area is not
necessarily the one which parks the maximum number
of vehicles, but the one that also provides ample stall
and aisle widths, pedestrian walks, adequate turning
radii, reasonable grades, efficient movement of traffic,
pleasant appearance, and convenient location.
29. In apartment and row house developments, it is
desirable to locate parking where conflicts between
autos and pedestrians are minimized. In large parking
lots, pedestrian walkways allowing people to move
safely should be used. In small parking areas,
walkways between fines of parked cars may be
difficult to justify in light of economy and proximity
to adjacent walks. Walkways lend a pleasant visual
pattem to the parking area, especially when planted.
Additional space should be provided where cars
overhang curbs.
Access Road
Property
Line
I. SITE PLANNING
Fig. 14: Interior and perimeter landscaping
reduce the visual affects of large paved parking
areas. Interior landscaping should be increased
as parking lots get larger.
A single 42 space parking ZOL
30. When do parking lots become too big? Four to
six spaces, is pedestrian and human in character,
while over twelve cars becomes "car dominated
territory." The critical number seems to be ten.
This marks the breaking point between a human lot
and a sea of cars. Small lots can be accomplished by
breaking large parking areas into sections divided
with landscape areas. Each section should serve not
more than 10 to 12 cars. Landscape islands and areas
should be located to protect cars as well as to break up
seas of asphalt.
31. A landscaped area shall be placed at the end of
each interior row in the parking area with no more
than 10 stalls between the landscape areas.
Parking area design should also incorporate the
following:
• All driveways onto public streets should be
located a minimum of 50 feet from the
intersection.
• All maneuvering needs should be provided for
entirely on-site.
• All areas not necessary for vehicular maneuvering
or parking should be landscaped.
Landscape areas within parking lots should not be
less than 5 feet in width and protected with
curbing.
An average 15 square feet of interior landscaped
area per parking space for parking areas with
more than 40 spaces should be provided as a
general rule. The minimum 12 square feet per
parking space is intended to be applied only in
unusual situations where site constraints severely
limit developable area or where superior site
design effectively break up the effects of large
paved areas and create a pedestrian friendly
design.
9
L SITE PLANNING
Fig. 15: Tandem parking spaces should only be used in
conjunction with under structure parking.
Entrance Areas
Fig. 16: Project entry provides an immediate
sense of high quality design.
32. The entrance to the site, building and individual
unit creates a transition between the outside public
world and a successively less public inner world.
Living units, with a graceful transition between the
outside and inside, are more tranquil than those which
open directly off the street or parking area. The
experience of entering a building influences the
perception of interior spaces. If the transition is too
abrupt, there is no feeling of arrival and the inside of
the home fails to be as private.
28
10
L SITE PLANNING
17: A high quality pedestrian entry is given
equal weight with auto entries.
SENH•FRIVATE
33. It is possible to make the transition in many
different physical ways. In some cases, for example,
it may just be inside the front doorr- a kind of entry
court, leading to another door or opening that is more
definitely inside. In another case, the transition may
be formed by a bend in the path that then moves
through a gate. Transition might also be provided by
changing the texture of the path, so that one steps off
the sidewalk onto a gravel path, and then up a step or
two under a trellis.
Some entry elements include:
• An accent tree which defines area with overhead
branches.
• A low wall for plants or draping vines.
• A trellis or arbor.
• A change in level.
• A change in path texture.
34. The most successful solution will consist of a
combination of the above suggested symbolic definers
or other comparable mechanisms.
11
I. SITE PLANNING
Solar Orientation
Fig. 18: Outdoor oriented recreation areas
maximize solar exposure.
Crime Prevention
Fig. 19: Site planning should create varying
degrees of privacy.
35. To maximize the warming effect of solar radiation
in winter months and maximize shade in the summer
months:
• Utilize deciduous trees for summer shade and
winter sun.
• Orient active living spaces to the south.
• Design building overhangs to shield the high
summer sun and expose the area to the lower
winter sun.
36. If possible, all buildings should be located and
oriented to take advantage of natural energy saving
elements such as the sun, landscape, and landform.
37. The opportunity (or invitation) for crime can be
greatly reduced through physical design and site
layoui Considerations for crime control should be
included at the project's inception. Where hardware
afterthoughts have been too heavily depended upon,
crime opportunities have continued to exist and crime
prevention has failed.
38. The Concept of Defensible Space should be
employed to reduce opportunities for crime.
"Defensible space" is a term used to describe a series
of physical design characteristics that maximize
resident control of behavior --particularly crime. A
residential development designed under defensible
space guidelines clearly defines all areas as either
public, semi -private or private. In so doing, it
determines who has the right to be in each space, and
allows residents to be confident in responding to any
questionable activity or persons within their complex.
Residents are thus encouraged to extend their private
realms, establish their zone of influence which
inevitably results in a heightened sense of
responsibility towards the care and maintenance of
these outdoor areas.
12
I. SITE PLANNING
Fig. 20: CuI de sacs create semi -private
"courts" to provide increased security and
informal play areas.
Fig. 21: Semi -private project areas are
separated from general public areas using
transitional spaces which are visually open in
design.
A br and step-up entry
define semiprivate project areas whik
maintaining a visuafly open streetscape.
39. A series of techniques can be used to create
defensible space and consequently reduce crime.
They are summarized in the following:
• Defining zones of privacy (public, semi -private,
private) with real or symbolic barriers. This
allows residents to identify "strangers".
Establishing perceived zones of influence
(allowing residents to extend their private realms).
Providing surveillance opportunities.
Additional design considerations include the
following:
Parking Layout. Parking for residents should be
located so that distances to dwellings are
minimized and allow easy surveillance from
nearby areas and windows.
• Orientation of Windows. Windows should be
located so that areas vulnerable to crime can be
easily surveyed by residents.
• Location of Service and Laundry Areas.
Laundry rooms should be located in such a way
that they are observed by others.
Windows and lighting should be incorporated to
assure surveillance opportunities.
• Mailboxes should not be located in dark alcoves
out of sight.
Barriers to Police. In semi-public and semi-
private areas, barriers which would hinder police
patrol, such as confused parking patterns and tall
shrubs, should be avoided.
13
I. SITE PLANNING
Fig. 22: A transition from semi -private to
private spaces with low volume paths, trellises
and alcoves.
Identity. A system for identifying the location of
each residential unit and common facilities at the
project entry should be establislrtl.
Hardware. Police department should be
contacted for information regarding appropriate
hardware such as door locks, window latches, etc.
Lighting. More light is not necessarily indicative
of better and safer lighting. Lighting levels
should be carefully selected and oriented so that
points and areas vulnerable to crime are accented.
Lighting should be provided in areas of heavy
pedestrian or vehicular traffic and in areas which
are dangerous if unlit, such as, stairs and ramps,
intersections or where abrupt changes in grade
occur. Areas that have high crime potential
should be well lighted so that people traveling
through them at night may feel secure.
Landscaping. Plant materials such as high
shrubs, should not be located so that surveillance
of semi-public and semi -private areas is blocked.
This will provide the opportunity for crime.
40. Sucker shrubs may discourage crime activities.
Low shrubs and umbrella trees (where the canopy is
maintained above 5 feet from the ground) will allow
surveillance opportunities, hence reducing the
potential for criminal behavior.
14
32
II. BUILDING DESIGN
Fig. 23: Multi -family building line and
proportions are harmonious with surrounding
single family dwellings.
HARMONIOUS BUILDING RNE
ROAD HARMONIOUS BUILDING PROPORTIONS
Fig. 24: Multi -family building shape, height
and length are similar to adjacent single family
buildings.
60%0"
SIMILAR BUILDING HEIGHT
WITHIN 60 FEET OF PROPERTY
LINE
SIMILAR ROOF G}IT AND SCALE
z
MULTI -FAMILY ZONE SINGLE FANIILY ZONE
1. Building design harmony with the surrounding
neighborhood should be emphasized. Building design
elements should include scale/mass, modulation,
height, the proportions of entries, windows and other
openings (fenestration), color, materials, and shapes.
This is not to require mimicry or that creativity is
prohibited. Only that the creative act be sensitive to
the neighborhood context. The City recognizes that
its neighborhoods are in constant change and that the
creative response to change is necessary in retaining
its valuable residential areas.
2. Portions of multi -family developments adjoining
Comprehensive Plan "Single Family Residence" areas
should maintain a scale, facade and orientation similar
to single family uses for compatibility with existing
structures. Surrounding single family neighborhood
building pattems may be used when adjacent single
family lots are vacant. A project site plan and cross-
sections should show the footprint of all adjacent
structures within 100 feet of the property line to help
evaluate compatibility.
3. Sloped roofs, minimum 5 ft. rise over 12 ft. run,
should be used on multi -family buildings to enhance
design harmony with surrounding single family
neighborhoods, and on steep slopes to enhance design
harmony with surrounding land forms. A 4-1/2 foot
rise may be appropriate in combination with wide
(i.e., 24 inch) overhangs, as may be mansard roofs in
special circumstances to lower buildings below the
tree or ridgeline.
15
II. BUILDING DESIGN
Fig. 25: No particular architectural design is
specified. However, the sum of a structure's
shape, fenestration, fine detailing and colors
should be superior architectural design which is
harmonious with the neighborhood.
balconies
french doors
vide detailing
hich helps avoid
architectural
monotony.
4. More prominent sites and architecture require a
higher level of design quality. This would include
projects which are located near hill tops or
intersections, or which include large visible building
masses.
5. Building design and siting should define a visual
focal point associated with each structure. A building
entry or open space often fulfills this role. Such a
focal point is denoted by structural articulation,
materials, and color for identity and interest. Shapes,
materials, colors and landscaping should also be used
to create a transitional sequence to the focal point.
Abrupt, design band aids, such as tacked on entry
alcoves and insignificant walks, should be avoided.
wow,
trf,
.
ijt
-
Aandsteprausesvcentral
pro, vCiedevaisulido-lveansebanlcon my
street level to the four story building
16
II. BUILDING DESIGN
Fig. 26: Minimum building separation.
30
20
10
6. Structures should be separated by a distance equal
to one-half the sum of the adjacent building heights.
Where a building has varying heights, each portion of
that building shall satisfy the separation requirement
(Fig. 25). The effect of topographic changes may be
considered.
7. Where building height exceeds 35 feet, the Board
of Architectural Review should apply the Design
Criteria to establish a building separation distance not
less than 35 feet.
8. Buildings should be separated at least 8 feet from
driveways and parking spaces where facing windowed
walls (but not the entry) of ground units and have a
minimum 13 foot separation when facing the entry of
ground units.
9. Buildings should be separated from common
walkways by at least 8 feet in the structure's front and
rear, and a minimum 4 feet on its side.
10. Separation guidelines should not apply to
incidental structures such as trellises, 18 inch roof
eaves, chimneys, covered walks, and pedestrian
oriented amenities.
*;•
OFT.(.1/2(20+20))
25FT.(..1/2(20+30))
17
II. BUILDING DESIGN
Fig. 27: Design details need not be costly to
significantly improve architectural quality.
11. A 3 -story blank wall, even if at the narrow end of
a building, does not reflect acceptable design quality.
Architectural relief and fine detailing should be used
to break up monotonous surfaces.
12. Avoid applied ornamentation which is not related
to building structure or architectural design. This
would include arbitrary, inconsistent forms and
decoration; uninterrupted floating horizontal
elements; and large blank surfaces.
13. All exterior maintenance equipment, including
HVAC, equipment, storage tanks, satellite dishes, and
garbage dumpsters should be screened from off-site
and on-site common area view, in an architecturally
integrated manner.
18
II. BUILDING DESIGN
Exterior Elevations
Fig. 28: Offsets, changes in materials, and
other fine detailing are used to provide
architectural interest.
14. The exterior elevations of buildings should
incorporate design features such as offsets, changes in
materials and shapes, to preclude large expanses of
uninterrupted building surfaces.
Additionally:
15. Structures shall not have an unbroken wall longer
than 60 feet.
16. Site design should avoid the dominance of large
individual building walls or the cumulative effect of
successive smaller building wall repetition. Building
separation and modulation should be sufficient to
visually break up wall masses. The measures needed
to visually break up wall masses will increase as a
project increases in size and cumulative building
mass. The minimum standards for this guideline are
specified in TMC 18.50.
d roofs, building modulauo
intimate envies introduce a single
scale to this dense building.
family
A trellised envy provides structural
transition from pedestrian environment to
building mass and helps separate public
from sani-private project spaces.
19
III. LANDSCAPE/SITE TREATMENT
Landscape Design
Fig. 29: Landscaping shown at 5 years after
planting.
Fig. 30: Live groundcover is planted to achieve
90% coverage within 3 years from installation.
Tune of plaruing
90% of coverage after 3 years
1. Plants can be used to curtail erosion, to soften the
built environment, define or emphasize open space,
give privacy, block wind and lessep the effects of solar
radiation.
2. Although the landscape plan should reflect plants at
maturity, landscaping should be considered as a design
element harmonizing site plans and building design
only to the extent of its effect in five years. This could
mean using significantly larger initial plant stock for
those project designs which rely heavily upon
landscaping to provide relief for building and site
design or screen the project.
4. Transition areas adjacent to buildings and parking
lots should be landscaped with a combination of trees,
shrubs, and ground cover. This provides a tiered visual
transition between the open and built environments, and
breaks up wall masses.
5. The design orientation for landscaped areas is
largely discussed in Section 1: Site Plan guidelines.
This section focuses on the technical standards to be
recognized in designing such landscape areas.
6. In general, landscape materials should be selected
, and sited to produce a hardy and drought -resistant
landscape area consistent with project design. Selection
should include consideration of soil type and depth,
- spacing, exposure to sun and wind, slope and contours
of the site, building walls and overhangs, and
compatibility of new plant material with existing
vegetation to be preserved on the site.
All plant materials should be installed to current
nursery industry standards which would include, but
not be limited to the following or equivalent:
• Landscape plant material should be properly guyed
and staked to current industry standards.
• Deciduous trees should be fully branched.
• Evergreen trees should be a minimum of 8 feet in
height at the time of planting.
• All plant rows should be staggered for effective
covering.
• Ground cover should be supplied at the time of
planting in minimum of 4 -inch containers as
appropriate to achieve 90% coverage in 3 years, or
as sod.
• Planting of trees in compacted soils should be
prohibited unless minimum 12 inch gravel drain
20
III. LANDSCAPE/SITE TREATMENT
Fig. 31: Landscaping along street frontages
should be high quality and reflect three tiers of
plants.
Fig. 32: Perimeter landscaping along the side
and rear lot lines provide year-round buffering
and transition.
PARK I NG
CURB/
WI IERI, STOP
0
PARKIN
BUMPER OVERI IA
sumps are installed under each tree to a minimum
36 inch depth, or the subgrade soil beyond the
planting pit is rototilled to a 9 inch depth to the drip
line or edge of planter, whichever is less.
Front yard plant material should reflect the following:
• shrubs, 2 gallons at time of planting
• deciduous trees to be minimum 2 1/2 inch caliper at
time of planting, balled and burlapped
• evergreen trees to be 8 - 10 feet in height at time of
planting, root balled and burlapped
• or equivalent per Board of Architectural Review.
Side and rear yard plant materials should reflect the
following:
• shrubs, 2 gallons at time of planting
• deciduous trees (Le. maples and ash) to be spaced
an avg. of 30 feet on center and 2-1/2 inch caliper
at time of planting, balled and burlapped
• evergreen trees (i.e. pine and fir) to be spaced an
avg. of 25 feet on center and 7 feet in height at time
of planting, balled and burlapped
• or equivalent per Board of Architectural Review.
Perimeter landscaping around parking areas should
reflect the following:
• tree planting 20 - 30 ft. on center depending upon
size (i.e., smaller species such as Japanese
flowering cherry should have 20 ft. o.c. spacing)
• perimeter shrub screen
• sluubs to be 2 gallons at time of planting, spaced to
achieve year-round screening to a 3 ft. height in
five years
• or equivalent per Board of Architectural Review.
Plant materials within parking areas should reflect the
following:
• evergreen trees to be 8 feet at time of planting,
balled and burlap
• deciduous trees to be 2 inch caliper at time of
planting
• 2 gallon shrubs.
Plants used for screening outdoor storage should consist
of shrubs, minimum of 18 inches in height (1 gallon or
larger) at the time of planting, spaced a minimum of 24
inches on center (or greater if larger plant material
used).
21
III. LANDSCAPE/SITE TREATMENT
Fig. 33: A typical shrub hedge separating use
areas with standard nursery stock.
7. Grass seeding should only be permitted between
April 1st and October 15th to assure germination.
Some form of erosion control will be necessary if
seeding is not completed during this period. Hydro -
seeding or mechanical spreading should be used on
• _
slopes.
8. Shrubs planted to define spaces or separate
environments should be planted as a staggered double
row whenever possible. This provides the significant
depth especially necessary to separate environments
such as parking areas from grassed fields and building
entries.
These shrubs should be spaced to provide a lush
continuous band within 3 years. This could be reflected
in a double staggered row of plants for typical nursery
stock spaced a maximum of 36 inches on center,
depending on the specific material.
9. Shrub beds should be no more than a two feet wide
per typical row of nursery stock plants, in order to
minimize barked area and maximize live ground cover.
A typical five foot wide barked planting bed for a
single row of shrubs is not acceptable.
10. Plant materials should generally include native
drought resistant species.
11. The native character of hillsides, ravines and
wetlands should be protected and enhanced to provide
habitat for a wide range of wildlife. Invasion and
takeover by more vigorously growing non-native
species such as English ivy; St. John's wort, and
Himalayan blackberry tend to exclusively promote
habitat for various rodent species.
12. Only native species which enhance a diverse habitat
should be planted on the remaining natural hillsides,
ravines, and wetlands. Plant buffer areas where the
selection of introduced species is carefully reviewed for
potential invasion of such natural areas should be
recognized on a site -by -site basis by the landscape
architect.
22
III. LANDSCAPE/SITE TREATMENT
Trees
13. Trees should be planted at an average rate of 1 per
30 linear feet of transition area (grouping is an option),
shrub beds should be designed as a staggered double
row, and ground cover should achieve 90% coverage in
3 years except for minimum (Le., 2 foot) planter beds.
Figures 35-37 show various options for separating uses.
14. Landscape design guidelines for required front, side
and rear perimeters are illustrated in figures 31 and 32.
15. Trees should generally be specimen quality, balled
and burlapped, and have a minimum size at planting as
shown below. This minimum tree size may be
increased based on the amount of buffering demanded,
prominence of location, and size necessary to realize
the applicant's assertion of landscape prominence
within five years.
16. An example of increasing tree size should be along
the street frontage when large paved areas are being
moderated or where dominating wall masses are being
softened. An example of decreasing tree size would be
where a stand of trees is being planted and only a few
specimen quality trees are needed to define the planting
area and provide visual planting depth. Typical
planting sizes are shown below:
, Tree Type Minimum Planting Size
Large stature deciduous
(i.e. maple, ash, oak)
Large stature evergreen
(i.e. pine or fir)
Small stature tree
(i.e. Japanese pear
or flowering dogwood)
2 1/2 inch caliper
8 ft. height
1 3/4 inch caliper
23
41
III. LANDSCAPE/SITE TREATMENT
Protection of Existing Trees
Fig. 34: Tree wells can help save hillside trees
only to a depth of 4 feet.
Fig. 35: Trees protected with a chain link fence
at the drip line during construction.
17. Significant existing trees should be protected as
discussed under Site Planning.
18. The survival and general health of a tree depends as
much on the condition of its root system as it does on
the factors influencing the above -ground portion. This
vital root system extends out to, and sometimes beyond
the tree's drip line (the outermost reach of branches).
Any significant disturbance to the root area, such as
high surface compaction, root severing, over -watering
and/or removal of organic material in which the tree has
composted over several years, will almost certainly kill
the tree. Tree removal and replacement would be
required after a few seasons of progressive
deterioration.
Based upon identification and examination, an
evaluation can be made to determine which trees will
prove valuable to the site design. This evaluation is an
important factor in the placement and design of
buildings, circulation patterns and other site elements.
19. Significant trees should be protected during
construction with a chain-link fence or plastic vinyl
construction fence at the drip line. The protection fence
should be installed prior to issuance of grading permit.
Removal or destruction of fencing should be cause for a
Stop Work Order until reviewed by City staff.
24
III. LANDSCAPE/SITE TREATMENT
Design for Screening
and Separation
Fig. 36: Separation of marginally compatible
uses with only plants.
20. Landscape design for screening and separation
can be oriented toward full privacy, separation of uses, or
screening unsightly elements such as dumpsters, etc.
21. Full privacy should require an opaque fence or
evergreen barrier at least six feet high or above eye level,
depending on the angle of view. Noise reduction requires
a dense fence (i.e., concrete/masonry) wall or berm in
addition to plantings.
22. Area separation requires a continuous physical barrier
not less than three feet high. A greater degree of
separation would require a higher opaque barrier. A
separation planting strip could be deciduous or evergreen.
23. Landscape design for screening should reflect the
degree of concealment desired. Plants are not often
effective in providing full screening; they should be used
in combination with a wall or landform. Plant screens are
most effective when used to soften or provide soft
transition to a screen wall or break up the visual lines of a
partially concealed structure.
24. A privacy fence should be required along side and
rear yards if adjoining single family zones as specified
below:
• 6 feet high
• sight -obscuring wood (or equivalent) fence
• exterior materials and colors shall be consistent with
building architecture.
25. The following are alternative design solutions for
various degrees of screening and separation:
Alternative 1. Using only plantings for partial separation
of marginally compatible uses such as parking from
residences or recreational _sites.
Area: Width not less than 15 feet.
At least one row of deciduous and evergreen trees
staggered and spaced not more than 15 feet apart.
At least one row of evergreen shrubs spaced not more than
five feet apart which will grow to form a continuous
hedge at least five feet in height within three years of
planting.
Lawn, low growing evergreen shrubs, and evergreen
ground cover covering the balance of the area.
25
III. LANDSCAPE/SITE TREATMENT
Fig. 37: Separation of marginally compatible
uses with fencing and plants.
Fig. 38: Full separation of incompatible uses
with masonry wall and plants.
Alternative 2. Using a fence and planting for full visual
separation of marginally compatible uses,
Area: Width not to be less than 10 feet.
At least one row of deciduous and/or evergreen shrubs
spaced not more than 5 feet apart.
Lawn, low growing evergreen shrubs, and evergreen
ground cover over the balance of the area.
Altentative 3. Using a wall and planting for full
§eparation of incompatible uses, This structural
approach is often the only effective mitigation of
impacts such as high freeway noise on outdoor
recreation areas.
Area: Width not to be less than 5 feet.
A masonry wall not less than 6 feet in height and no
less than 5 feet of landscaping transition.
26
44
III. LANDSCAPE/SITE TREATMENT
Interior Parking Area Landscaping
Usable Outdoor Space
Recreation Area Design
Fig. 39: Recreation area design for safety
includes siting the children's play lot in a
central or easily observed area.
PUBLIC OPEN SPACE COM
PRIVATE OPEN SPACE
26. Minimum parking area landscaping at the perimeter
and interior areas are specified in Chapter 18.52 of the
Tukwila Zoning Code. Design concepts for these areas
are shown in figures 11, 12, 13 and 32.
27. As much design emphasis should be put into
developing outdoor spaces as the buildings themselves.
Outdoor space tends to be unusable when it is simply
the "leftovers" after buildings are placed on the land.
(See Fig. 6)
28. Buildings or other substantial structures should be
used to reduce the impact of noise sources when such
noise would interfere with normal conversation as
identified in Federal Environmental Protection Agency
guidelines (i.e., 55-65 dBa).
29. Outdoor spaces should have a definite functional
shape, be internally designed to fulfill that function, and
be functionally associated with a specific unit or unit
group (see "Defensible Space" in Site Plan guidelines).
30. A full range of active and passive recreation
opportunities should be provided for the various
resident age groups: infant (04), child (5-12), teen (13-
18), and adult.
31. Infant needs may be satisfied by passive spaces and
overlap with child facilities.
32. The child group is the critical group for on-site
recreation design since members tend to use facilities
independent of parental supervision, are not necessarily
old enough to travel streets to relatively distant public
parks, and make complex demands of recreation spaces.
27
III. LANDSCAPE/SITE TREATMENT
Fig. 40: A recreation space for the 5-12 year
old group which facilitates group interaction
and skill testing.
33. At least one on-site play area designed for the child
group should be provided. This area design should be
characterized by interactive group equipment which
tests skills. The Parks and Recreation Director should
be consulted in the review of acceptable design
proposals.
34. The child play area should reflect the design
elements below:
• Visually accessible to casual surveillance by
passersby and residents. This is a key element in
facility safety and generally requires a central location.
Care should be taken to provide separation of play
areas from general impersonal passersby for
security.
• Easy safe access from residence to play area(s).
• Hard surface areas for wheeled toys and tricycles.
• Equipment with zones to satisfy the specific
sensory and skill needs up to age 12.
Use water and sand if limited to two materials.
These provide more possibilities for play and fun
than all asphalt deserts combined. The ability to
move over, under, around or through something
affords a child control. He can change his
relationship to it.
• A child should be able to control his level of
involvement with others. Make small sheltered
areas for solitary play, larger spaces for group play.
• An adjacent sitting area for monitoring the children.
35. Teen and adult on-site recreation facility demand
may be satisfied with active recreation fields and sport
courts, recreation rooms, pools and passive recreation
trails. Linkages with existing public trail and park
facilities should be made where possible, either through
immediate construction or agreement to jointly
participate in the coordinated provision of such a
linkage at a later date.
28
IV. MISCELLANEOUS STRUCTURES/STREET FURNITURE
Lighting
Fig. 413 Maximum parking area light standard
height is 20 feet or the building height;
whichever is less.
Fig. 42: Maximum grounds lighting standard
height is 15 feet.
1. All exterior lighting (i.e., distribution, intensity,
and pattem) should reflect project architectural
design.
2. Exterior lighting should be provided in parking
areas and along internal pedestrian walkways to
assure adequate and safe pedestrian circulation for
residential activities and guests.
3. Maximum parking area light standard height
should be 20 feet or the height of the building;
whichever is less.
4. Maximum walkway and grounds lighting should
be 15 feet. Light fixture height is limited to enhance a
sense of scale and enclosure for common areas at
night.
5. All lighting standards should have glare cut-off
features to avoid off-site spill-over.
6. Fixtures should be placed so that light pattems
overlap at a height of 7 feet which is sufficiently high
to vertically illuminate a person's body. This is
particularly important consideration now that lighting
fixture manufacturers are designing luminaries with
highly controlled light pattems.
7. At hazardous locations, such as changes of grade,
lower level supplemental lighting or additional
overhead units should be used. Where low-level
lighting (below 5 feet) is used, fixtures should be
placed in such a way that they do not produce glare.
Most eye levels occur between 3 feet 8 inches for
wheelchair users and 6 feet for standing adults.
8. The walkway lighting is provided primarily by
low fixtures, there should be sufficient peripheral
lighting to illuminate the immediate surroundings.
Peripheral lighting contributes to a feeling of security
in an individual because he can see into his
surroundings to determine whether or not passage
through an area is safe. Such an area should be
lighted so that the object or person may be seen
directly or in silhouette.
29
IV. MISCELLANEOUS STRUCTURES/STREET FURNITURE
Fencing, Walls, and Screening
Fig. 43: Dumpsters are sited and screened to
minimize prominence.
Street Furniture
9. All fencing, walls, and screening should reflect
building architecture and be harmonious with adjacent
project designs. This should include consideration of
proportion, color, texture, and materials. Perimeter
fencing should be designed to be attractive from both
sides.
10. Fencing and walls along street frontages should
define space but be designed to be visually open and
inviting to support a lively pedestrian environment.
11. All exterior mechanical equipment including
HVAC, electrical equipment, storage tanks and
satellite dishes, must be screened from on-site and
off-site view.
12. Several small dumpsters adjacent to buildings
such as garages are preferable to a single large free
standing site. Dumpsters should have solid
architectural wall screening only to the container
height to minimize its prominence.
13. Recycling containers and areas should conform to
King County standards or as amended by Tukwila
standards.
14. All garbage container lids should be light weight
and designed for operation by physically frail persons.
15. Street furniture should be coordinated to carry out
the project's design concept.
16. Opportunities for social gathering by residents in
shared open spaces should be enhanced by the
provision of seating and other amenities. The use of
bollards and other barrier features should be provided
to separate vehicular traffic from pedestrian -oriented
areas.
30
48
ACKNOWLEDGEMENTS
No set of design standards can be done without heavy reliance on past studies and
documents. The following is a partial list of documents which were heavily used or
contained the basis of design standards, concepts or illustrative graphics.
American Planning Association, Chicago, IL; "Planning News"
City and County of San Francisco, CA; 07189; "Residential Design Guidelines"
City of Seattle, WA; 01192; "Proposed Design Review Process and Guidelines for the Cu)
Seattle" (Draft)
City of San Jose, CA; 1186; "Residential Design Guidelines for the City of San Jose"
City of Anaheim, CA; 12/91; "Residential Design Guidelines" (Draft)
Greenman Group (The), Hollywood, FL; "Development Digest"
Irvine Company (The), CA; 01187; "Tustin Ranch Design Guidelines"
National Association of Home Builders, Wash. D.C.; 1986; Higher Density Housing:
Planning, Design, Marketing
National Association of Home Builders, Wash. AC; 1990; Seminar and Materials on
"Making Small Lots Work: Innovative Land Use for Single Family Homes"
Newman, Oscar; 1975; Design Guidelines for Creating Defensible Space
Multnomah County, OR; 11177; "A Developer's Handbook"
Urban Land Institute, Wash. D.C.; "Urban Land"
49