UNDERSTANDING DENSITY
7 Design Considerations for Comfortable Density and 26 Massing Variations for a Two-Acre Block
Density Alphabet Set Which densities, attributes, and amenities will best serve your future neighborhood needs?
The Holistic Housing Lab is a design-centered research platform dedicated to exploring housing as an interconnected system shaped by people and place. © 2026 Karla Sierralta & Brian Strawn
DENSITY ALPHABET: SEVEN STRATEGIES FOR COMFORTABLE DENSITY
In this set: • 26 Massing Variations For a 2-acre block • 7 Design Considerations For Comfortable Density
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DENSITY ALPHABET
At a glance The 26 massing studies presented in the “Density Alphabet” focus on formal and organizational implications, such as positioning, the orientation of spaces, volume attributes, and location of openings. There are seven design considerations that informed the alphabet based on the experience of pedestrians and residents. •
Permeability at grade
•
Massing & Proportion of Street-facing Volumes
•
Programming at Street Level
•
Parking & Mobility
•
Unit Mix
•
Floor Plan Layout
•
Building Massing & Organization
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DENSITY ALPHABET
What’s on the card? Design Consideration Card
Design Consideration Affecting pedestrian or residential experiences
Design Action Reference Number Reference to Imagine Your Community Cards
Diagram Illustrating considerations
Design Action Reference number and action name
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DENSITY ALPHABET
At a glance The Density Alphabet presents 26 massing variations for multi-use housing projects from low to high rise.
DENSITY RANGE
D/U ACRE
FAR
50-100
64
1.27
B
77
1.53
C
79
1.58
D
84
1.67
E
88
1.75
F
93
1.85
G
A
100-200
111
2.17
H
118
2.29
I
120
2.35
J
124
2.42
K
129
2.53
L
136
2.65
All studies based on Lot size: 90,000 sf
M
137
2.68
Acres:
N
142
2.77
O
145
2.84
P
146
2.85
Q
149
2.92
R
177
3.45
2.07
S
182
3.56
T
186
3.62
U
200-500
306
5.85
V
349
6.67
W
351
6.71
X
356
6.81
Y
358
6.85
Z
500
9.56
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DENSITY ALPHABET
What’s on the card? Density Alphabet Card
Reference Letter Organized from low to High rise and density ranges
Isometric Overall view of the massing highlighting uses, open space, communal terraces, and shared roof gardens. See color key.
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Dwelling Units per Acre Key metric for comparing densities Unit Count Total dwelling units for this massing
Floor Area Ratio The percentage of built space compared to the size of the site
Stories Number of stories in towers and podiums
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DENSITY ALPHABET
Variation Ranges DENSITY RANGE 50-100
100-200
Variations of U-Z with lower heights. High-Rise 13-40 Stories
Possible, iterations risk inefficient use of space.
200-500
U-Z
Explore 3-6 story podiums with towers up to 39
BUILDING HEIGHT
stories.
Variations of G-T with lower heights, Mid-Rise 5-12 Stories
or variations of A-F with additional towers.
G-T
Explore 2-6 story podiums with towers up to 12 stories.
Low-Rise 1-4 Stories
A-F
Explore 4-story walk-ups and
Iterations risk overcrowding
podiums, no towers.
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DENSITY ALPHABET
Color Key •
Residential — Residential floors and rooftops
•
Potential Terraces — Rooftops in-sight within the property with potential for common terraces. Light to dark from lowest to highest off ground plane.
•
Flex/Commercial — Potential spaces for other uses or residential at grade
•
Open Space — Open spaces at grade
•
Parking — At grade, in structures
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DENSITY ALPHABET
Think about:
Which densities, attributes, and amenities will best serve your future neighborhood needs?
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DENSITY ALPHABET
Sort by: • Density Range • Dwelling Units per Acre • Floor Area Ratio
Pair with: • Case Study Cards
Compare to: • Imagine Your Community Cards Building Realm
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DENSITY ALPHABET: SEVEN DESIGN CONSIDERATIONS FOR COMFORTABLE DENSITY
DES I G N C O N S I D E R A T I O N S
“IMAGINE YOUR COMMUNITY” DESIGN STRATEGY & ACTION*
Permeability at grade
3.2
4.2
5.1
6.1
7.1
12.1
Pedestrian experience
Permeability at grade offers opportunities for common or public areas, allows rain water to percolate naturally and creates more walkable communities by inviting pedestrians to cross large blocks.
* 3.2 Weave in parks and plazas; 4.2 Democratize the street; 5.1 Foster water consciousness; 6.1 Multiply productive lands; 7.1 Power active lifestyles; 12.1 Take play seriously.
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DENSITY ALPHABET: SEVEN DESIGN CONSIDERATIONS FOR COMFORTABLE DENSITY
DES I G N C O N S I D E R A T I O N S
“IMAGINE YOUR COMMUNITY” DESIGN STRATEGY & ACTION*
Massing & Proportion
4.1
4.2
Pedestrian experience
Lower structures along the street hide taller structures from pedestrian view. The proportion of these volumes should consider human scale and urban continuity.
* 4.1 Respect human scale; 4.2 Democratize the street
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DENSITY ALPHABET: SEVEN DESIGN CONSIDERATIONS FOR COMFORTABLE DENSITY
DES I G N C O N S I D E R A T I O N S
“IMAGINE YOUR COMMUNITY” DESIGN STRATEGY & ACTION*
Programming at street level
2.1
3.1
3.3
5.2
6.3
8.3
9.3
11.1
Pedestrian experience
Designing for the cross ventilation and natural lighting requirements of the most restrictive uses (i.e. with residential) allows for programmatic flexibility and adaptability.
* 2.1 Facilitate friendly interactions; 3.1 Promote hybrid neighborhoods; 3.3 Blend civic spaces into daily life; 5.2 Leverage cross-breezes; 6.3 Spark skill sharing; 8.3 Anticipate future change; 9.3 Activate micro-businesses; 11.1 Set aside flex space
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DENSITY ALPHABET: SEVEN DESIGN CONSIDERATIONS FOR COMFORTABLE DENSITY
DES I G N C O N S I D E R A T I O N S
“IMAGINE YOUR COMMUNITY” DESIGN STRATEGY & ACTION*
Parking & Mobility
4.3
8.3
Pedestrian experience
Commercial or green spaces can serve as visual buffers to hide parking from street and residential living. Spaces for parking should be designed with flexibility in mind to accommodate other modes of transportation (i.e. bikes, car sharing) and consider future conversion to other uses.
* 4.3 Amplify community mobility; 8.3 Anticipate future change
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DENSITY ALPHABET: SEVEN DESIGN CONSIDERATIONS FOR COMFORTABLE DENSITY
DES I G N C O N S I D E R A T I O N S
“IMAGINE YOUR COMMUNITY” DESIGN STRATEGY & ACTION*
Unit Mix
1.1
7.2
11.2
Residential experience
A mix of residential units in a variety of shapes and sizes promotes a diversity of occupants.
* 1.1 Enable co- and multi-generational living; 7.2 Provide lanais for all; 11.2 Prioritize flexibility and variety
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DENSITY ALPHABET: SEVEN DESIGN CONSIDERATIONS FOR COMFORTABLE DENSITY
DES I G N C O N S I D E R A T I O N S
“IMAGINE YOUR COMMUNITY” DESIGN STRATEGY & ACTION*
Floor Plan Layout
5.2
7.2
8.2
11.2
Residential experience
Single loaded corridors allow operable windows on two sides. Double loaded corridors with bays or corridors open to the exterior also offer potential for cross ventilation. Other open spaces can serve as inhabitable terraces, shared spaces for gardens or play.
* 5.2 Leverage cross-breezes; 7.2 Provide Lanais for all; 8.2 Aim for efficiency; 11.2 Prioritize flexibility and variety
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DENSITY ALPHABET: SEVEN DESIGN CONSIDERATIONS FOR COMFORTABLE DENSITY
DES I G N C O N S I D E R A T I O N S
“IMAGINE YOUR COMMUNITY” DESIGN STRATEGY & ACTION*
Building Massing & Organization
2.1
2.3
5.2
5.3
7.2
7.3
Residential experience
Offset or perpendicularly arranged volumes allow for unobstructed views from main living areas. Spacing in between structures permits flow of natural light and ventilation.
* 2.1 Facilitate friendly interactions; 2.3 Open sigh lines; 5.2 Leverage cross-breezes; 5.3 Mind the sun; 7.2 Provide lanais for all; 7.3 Protect views and privacy
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DENSITY ALPHABET: 26 MASSING VARIATIONS FOR A TWO-ACRE BLOCK
A
64
Low-Rise
Dwelling Units per Acre
Density Range 50-100
Total Units 131
Hig
1.27
Floor Area Ratio
4
Stories
h-r
Mi
ise
d-r
Lo
w-
ise
ris
e
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DENSITY ALPHABET: 26 MASSING VARIATIONS FOR A TWO-ACRE BLOCK
B
77
Low-Rise
Dwelling Units per Acre
Density Range 50-100
Total Units 158
Hig
1.53
Floor Area Ratio
4
Stories
h-r
Mi
ise
d-r
Lo
w-
ise
ris
e
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DENSITY ALPHABET: 26 MASSING VARIATIONS FOR A TWO-ACRE BLOCK
C
79
Low-Rise
Dwelling Units per Acre
Density Range 50-100
Total Units 164
Hig
1.58
Floor Area Ratio
4
Stories
h-r
Mi
ise
d-r
Lo
w-
ise
ris
e
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DENSITY ALPHABET: 26 MASSING VARIATIONS FOR A TWO-ACRE BLOCK
D
84
Low-Rise
Dwelling Units per Acre
Density Range 50-100
Total Units 173
Hig
1.67
Floor Area Ratio
4
Stories
h-r
Mi
ise
d-r
Lo
w-
ise
ris
e
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DENSITY ALPHABET: 26 MASSING VARIATIONS FOR A TWO-ACRE BLOCK
88
E Low-Rise
Dwelling Units per Acre
Density Range 50-100
Total Units 182
Hig
1.75
Floor Area Ratio
4
Stories
h-r
Mi
ise
d-r
Lo
w-
ise
ris
e
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DENSITY ALPHABET: 26 MASSING VARIATIONS FOR A TWO-ACRE BLOCK
93
F Low-Rise
Dwelling Units per Acre
Density Range 50-100
Total Units 192
Hig
1.85
Floor Area Ratio
4
Stories
h-r
Mi
ise
d-r
Lo
w-
ise
ris
e
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DENSITY ALPHABET: 26 MASSING VARIATIONS FOR A TWO-ACRE BLOCK
G
111
Mid-Rise
Dwelling Units per Acre
Density Range 100-200
Total Units 230
Hig
2.17
Floor Area Ratio
12
Stories
12 Tower 2-4 Podium
h-r
Mi
ise
d-r
Lo
w-
ise
ris
e
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DENSITY ALPHABET: 26 MASSING VARIATIONS FOR A TWO-ACRE BLOCK
H
118
Mid-Rise
Dwelling Units per Acre
Density Range 100-200
Total Units 243
Hig
2.29
Floor Area Ratio
6
Stories
0 Tower 6 Podium
h-r
Mi
ise
d-r
Lo
w-
ise
ris
e
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DENSITY ALPHABET: 26 MASSING VARIATIONS FOR A TWO-ACRE BLOCK
120
I Mid-Rise
Dwelling Units per Acre
Density Range 100-200
Total Units 249
Hig
2.35
Floor Area Ratio
12
Stories
12 Tower 3-4 Podium
h-r
Mi
ise
d-r
Lo
w-
ise
ris
e
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DENSITY ALPHABET: 26 MASSING VARIATIONS FOR A TWO-ACRE BLOCK
124
J Mid-Rise
Dwelling Units per Acre
Density Range 100-200
Total Units 256
Hig
2.42
Floor Area Ratio
12
Stories
12 Tower 4 Podium
h-r
Mi
ise
d-r
Lo
w-
ise
ris
e
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DENSITY ALPHABET: 26 MASSING VARIATIONS FOR A TWO-ACRE BLOCK
K
129
Mid-Rise
Dwelling Units per Acre
Density Range 100-200
Total Units 267
Hig
2.53
Floor Area Ratio
12
Stories
12 Tower 3-4 Podium
h-r
Mi
ise
d-r
Lo
w-
ise
ris
e
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DENSITY ALPHABET: 26 MASSING VARIATIONS FOR A TWO-ACRE BLOCK
136
L Mid-Rise
Dwelling Units per Acre
Density Range 100-200
Total Units 281
Hig
2.65
Floor Area Ratio
12
Stories
12 Tower 4 Podium
h-r
Mi
ise
d-r
Lo
w-
ise
ris
e
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DENSITY ALPHABET: 26 MASSING VARIATIONS FOR A TWO-ACRE BLOCK
M
137
Mid-Rise
Dwelling Units per Acre
Density Range 100-200
Total Units 283
Hig
2.68
Floor Area Ratio
12
Stories
12 Tower 4 Podium
h-r
Mi
ise
d-r
Lo
w-
ise
ris
e
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DENSITY ALPHABET: 26 MASSING VARIATIONS FOR A TWO-ACRE BLOCK
N
142
Mid-Rise
Dwelling Units per Acre
Density Range 100-200
Total Units 294
Hig
2.77
Floor Area Ratio
6
Stories
0 Tower 6 Podium
h-r
Mi
ise
d-r
Lo
w-
ise
ris
e
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DENSITY ALPHABET: 26 MASSING VARIATIONS FOR A TWO-ACRE BLOCK
O
145
Mid-Rise
Dwelling Units per Acre
Density Range 100-200
Total Units 300
Hig
2.84
Floor Area Ratio
12
Stories
12 Tower 3-4 Podium
h-r
Mi
ise
d-r
Lo
w-
ise
ris
e
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DENSITY ALPHABET: 26 MASSING VARIATIONS FOR A TWO-ACRE BLOCK
146
P Mid-Rise
Dwelling Units per Acre
Density Range 100-200
Total Units 302
Hig
2.85
Floor Area Ratio
12
Stories
12 Tower 4 Podium
h-r
Mi
ise
d-r
Lo
w-
ise
ris
e
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DENSITY ALPHABET: 26 MASSING VARIATIONS FOR A TWO-ACRE BLOCK
Q
149
Mid-Rise
Dwelling Units per Acre
Density Range 100-200
Total Units 309
Hig
2.92
Floor Area Ratio
12
Stories
12 Tower 4 Podium
h-r
Mi
ise
d-r
Lo
w-
ise
ris
e
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DENSITY ALPHABET: 26 MASSING VARIATIONS FOR A TWO-ACRE BLOCK
R
177
Mid-Rise
Dwelling Units per Acre
Density Range 100-200
Total Units 365
Hig
3.45
Floor Area Ratio
12
Stories
12 Tower 2-4 Podium
h-r
Mi
ise
d-r
Lo
w-
ise
ris
e
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DENSITY ALPHABET: 26 MASSING VARIATIONS FOR A TWO-ACRE BLOCK
182
S Mid-Rise
Dwelling Units per Acre
Density Range 100-200
Total Units 377
Hig
3.56
Floor Area Ratio
12
Stories
12 Tower 03 Podium
h-r
Mi
ise
d-r
Lo
w-
ise
ris
e
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DENSITY ALPHABET: 26 MASSING VARIATIONS FOR A TWO-ACRE BLOCK
T
186
Mid-Rise
Dwelling Units per Acre
Density Range 100-200
Total Units 383
Hig
3.62
Floor Area Ratio
12
Stories
12 Tower 03 Podium
h-r
Mi
ise
d-r
Lo
w-
ise
ris
e
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DENSITY ALPHABET: 26 MASSING VARIATIONS FOR A TWO-ACRE BLOCK
U
306
High-Rise
Dwelling Units per Acre
Density Range 200-500
Total Units 632
Hig
5.85
Floor Area Ratio
39
Stories
39 Tower 04 Podium
h-r
Mi
ise
d-r
Lo
w-
ise
ris
e
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DENSITY ALPHABET: 26 MASSING VARIATIONS FOR A TWO-ACRE BLOCK
V
349
High-Rise
Dwelling Units per Acre
Density Range 200-500
Total Units 721
Hig
6.67
Floor Area Ratio
39
Stories
39 Tower 04 Podium
h-r
Mi
ise
d-r
Lo
w-
ise
ris
e
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DENSITY ALPHABET: 26 MASSING VARIATIONS FOR A TWO-ACRE BLOCK
W
351
High-Rise
Dwelling Units per Acre
Density Range 200-500
Total Units 725
Hig
6.71
Floor Area Ratio
39
Stories
39 Tower 06 Podium
h-r
Mi
ise
d-r
Lo
w-
ise
ris
e
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DENSITY ALPHABET: 26 MASSING VARIATIONS FOR A TWO-ACRE BLOCK
X
356
High-Rise
Dwelling Units per Acre
Density Range 200-500
Total Units 736
Hig
6.81
Floor Area Ratio
39
Stories
39 Tower 04 Podium
h-r
Mi
ise
d-r
Lo
w-
ise
ris
e
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DENSITY ALPHABET: 26 MASSING VARIATIONS FOR A TWO-ACRE BLOCK
Y
358
High-Rise
Dwelling Units per Acre
Density Range 200-500
Total Units 740
Hig
6.85
Floor Area Ratio
39
Stories
39 Tower 03 Podium
h-r
Mi
ise
d-r
Lo
w-
ise
ris
e
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DENSITY ALPHABET: 26 MASSING VARIATIONS FOR A TWO-ACRE BLOCK
500
Z High-Rise
Dwelling Units per Acre
Density Range 200-500
Total Units 1,033
Hig
9.56
Floor Area Ratio
39
Stories
39 Tower 04 Podium
h-r
Mi
ise
d-r
Lo
w-
ise
ris
e
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