This slide deck serves as the pitch for a project to produce a standardized design, manufacturing, and implementation procedure for panelized ADUs in the Bay Area.
2. Bay Area
Housing Crisis
The Bay Area has added nearly two jobs
for every housing unit built since 1990.
This imbalance has been further
exacerbated by widening gaps between
high- and low-income households as
well as deficits in affordable housing
production. These conditions have
contributed to core regional challenges
like traffic congestion, affordability,
displacement, and homelessness.
3. EPA: Low Income
Homeownership
The challenges of suburbia are
compounded in low-income,
predominantly immigrant communities
like East Palo Alto, where families are
slowly being priced out of their own
neighborhoods. Feeling the desperation,
many homeowners are finding their
own solutions, converting structures
like garages into living areas for multiple
families. Done without going through
the city’s approval process, however,
and this creates unsafe environments
that don’t meet legal housing
requirements.
4. Forced into
Suburbia
One major barrier to the production of
more housing is the significant portion
of urban land that is zoned for R-1
single-family residential development.
Suburban communities have strong
incentives to preserve their property
values and sense of neighborhood
identity, forcing local and state politics
into gridlock when in comes to policies
allowing for incremental upzoning.
5. The low-hanging fruit of affordable
housing is in the spacious backyards of
many R-1 parcels. Accessory Dwelling
Units (ADUs) are 300-700 sf structures
with their own bathroom and kitchen
that could easily utilize undeveloped
space.
Can we make it cheaper and easier for
homeowners to build an ADU in their
backyards?
Vision: Accessory
Dwelling Units
6. Economic Benefits
As smaller units that integrate directly
into suburban environments, ADUs are
the most affordable way to increase
safe and convenient housing exactly
where it is needed. They will increase
the value of the properties for those
who install them on their lot, and the
increase in property tax will provide
much-needed revenue stream for
chronically under-resourced city
governments. The construction will use
local labor, and with more residents to
fill in empty space, local commercial
businesses will see more customers as
well.
7. Social Benefits
ADUs can be rented out to students or
couples. Empty nesters can move into
the ADUs and rent out their main homes
to larger families. ADUs can even be
paired with supportive service programs
to temporarily house the homeless.
People created by Rawpixel.com -
Before:
After:
8. Environmental
Benefits
ADUs by design have a smaller
environmental footprint and limit the
continued sprawl of suburban growth
by densifying existing residential
neighborhoods. This can reduce traffic
by placing people closer to their places
of work, and add revenue to local
governments by increasing the use of
regional public transit. ADU projects can
also enable much-needed retrofits to
existing single-family homes to reduce
energy and water consumption, with
the possibility of the ADU addition
having a net-zero impact on resource
consumption of the parcel.
Retrofits
and new
technologies
increase
efficiency
New ADU
consumes
energy
Installed
solar
produces
energy
Existing
home
consumes
energy
Net Zero
Change
9. Policy Barriers
A major barrier to ADU development is
in some unintentionally restrictive local
policies: zoning restrictions such as
minimum lot size for ADU eligibility,
building codes that uniquely challenge
small additional units, and an onerous
permitting process made worse by
oversubscribed city staff. The informal
evidence of this is the many
homeowners that choose to implement
ADU projects illegally, leading to safety
issues and code enforcement that
residents perceive as antagonistic.
10. Policy Solutions
Technology can play a critical role in
alleviating the permitting bottleneck by
streamlining digital submittals and
review of ADU projects, as well as
increasing ADU viability by clearly
demonstrating the impact of zoning
changes to city staff. We have been
working with the City of EPA, San
Mateo County, and other partners to
develop such tools.
11. Decision Barriers
Even under favorable policy conditions,
our neighborhoods may still not have
the information or incentives to initiate
and complete ADU projects. For
individual — and especially working —
families, the time investment required
to understand and plan an ADU without
technical expertise is simply too large.
Much of the critical information that
influences the ADU decision
fundamentally depends on site-specific
analysis, which is often expensive and
hard to organize.
12. Decision Solutions
Technology can also play a critical role
in nudging homeowners to initiate the
ADU process, whether by disseminating
compelling stories about benefits of
ADUs, empowering website users with
property-specific information about
ADU options and costs, or guiding them
through the full permitting process
automatically online.
13. Construction
Barriers: On-site
Even if policy and decision barriers were
fully alleviated, Bay Area neighborhoods
would still struggle to scale ADU
production at the current costs and
complexities of residential construction. The
materials and labor cost of on-site
construction average over $200/sf, meaning
that a 500 sf ADU is likely to cost over
$100,000, beyond what many homeowners
can afford. In addition, placing a detached
ADU in a backyard can be challenging given
narrow lot size, obstructions to cranes (for a
modular unit) like trees and powerlines, and
narrow, winding streets full of neighbors
who would be impacted by construction
operations.
14. Solution:
Panelized ADU
Our solution combines the benefits of
on-site and off-site industrialized
construction through a panelization
method. Flat, standardized sections of
floors, walls, and roofs would be built in
a controlled and optimized factory
setting, shipped by truck to the site,
conveyed through a track system
through the side yard to the backyard,
and then assembled using lightweight
tools.
15. Design Benefits:
Constructability
A panelized system unlocks many
single-family sites that are too narrow
or obstructed to receive a full modular
unit craned over the main house. Every
R-1 lot can be guaranteed to have a side
yard width of at least 3 feet, which
would be the minimum design
condition for our conveyance system.
The result is an accelerated assembly
process in the backyard with large
prefabricated elements that reduce the
noise and traffic impacts on the
neighborhood while still maintaining a
critical role for local labor.
16. Design Benefits:
Customizability
Panelized ADUs allow for customizable
floor plans that meet the particular
needs of homeowners in terms of ADU
size, number of bedrooms, and finish
style, all still based on a small number of
unique parts. An online web tool could
allow homeowners to search for their
address and visualize the largest ADU
that can legally be built in their
backyard, enabling as much quality
housing as possible with each
development.
17. Design Benefits:
Cost Reduction
Standardized panel sections can be
manufactured in a factory at economies
of scale for less cost than on-site
custom construction. Shipment of
panels is also more efficient than
shipping full spatial volumes, akin to
IKEA’s strategy with furniture. The end
result would be ADUs that fall
consistently under $100,000 in
construction cost, and potentially
including permitting fees if the
approvals process is also streamlined
using a digital design platform.
Source: City Lab/Katerra
18. Alternative Use:
Attached ADU
ADUs do not have to be standalone
backyard units: they can also be
conversions of the garage or other parts
of the existing home, or be installed as
additions to the existing home. These
could potentially use the same basic
panels, leading to even more affordable
options for expanding capacity of single
family lots.
19. Project Proposal:
Panelized ADU
We propose the completion of a
prototype panelized ADU from design
to operation in order to document the
full process and demonstrate the
feasibility of a <$100,000 ADU project.
The key steps include:
1. Identify a recipient and select an
optimal panelized ADU design
2. Produce full construction
documentation along with
permit approvals
3. Identify a factory, or site that
simulates a factory, and
prefabricate the panels
4. Deliver and assemble the ADU
20. Precedent:
Stanford Solar Decathlon
Stanford completed a similar
demonstration project when it competed
in the 2013 Solar Decathlon. With the
support of the Carpenter’s Union and
other sponsors, students designed,
engineered, and constructed a 1000 sf
net-zero home on Stanford campus. They
also disassembled the house into
modules for shipment to a competition
site in Southern California. Stanford’s
Sustainable Urban Systems Initiative
could help to administer similar formats
for engagement, providing a simulated
factory site, student participation, and
other useful academic resources.
21. Outcomes:
Demonstration Story
This prototype ADU project would yield
many important outcomes, including a
powerful story around co-production of
knowledge between academic, public,
private, and social sector stakeholders
which can disseminate through existing
networks and programs to the broader
Bay Area audience. Such a
demonstration could attract much
larger support and grassroots
participation in many other
communities.
22. Outcomes:
Open-Source Documentation
This project would also include
extensive documentation of the full
process and lessons learned, including
open-source drawings, data, tools, and
qualitative assessment from
stakeholders. This would be useful to
practitioners, residents, and other city
officials for years to come.
23. Outcomes:
Building Science Research
Given an academic partner, the
prototype ADU project would also have
the co-benefit of serving academic
research, particularly based on
instrumentation of the ADU with the
ability to track heating/cooling,
energy/water consumption, and human
comfort. The manufacturing process
could be approached from a theory-
driven background in industrialized
construction processes, and students
could conduct a life cycle assessment of
the entire project process to track
holistic environmental and economic
impacts.
24. Resource Needs
For this project to be successful, it needs the following key
resources:
1. Eligible site and receiving property owner
2. Partner city with staff support to streamline
permitting process
3. Factory or site for prefabrication process
4. Subject-matter experts to help with design and
construction
5. Monetary and in-kind donations
6. Support from key organizations to disseminate
findings
25. Resource Needs
For this project to be successful, it needs the following key
resources:
1. Eligible site and receiving property owner
2. Partner city with staff support to streamline
permitting process
3. Factory or site for prefabrication process
4. Subject-matter experts to help with design and
construction
5. Monetary and in-kind donations
6. Support from key organizations to disseminate
findings
These resources needs could be met with partners like:
1. Local nonprofits that work with low-income
homeowners, like Soup
2. East Palo Alto or North Fair Oaks
3. Stanford University, Factory_OS, VHD
4. Carpenter’s Union, VHD, RAD Urban
5. Chan Zuckerberg Initiative, Silicon Valley Community
Foundation
6. CASA, San Mateo County Home For All, Housing Trust
Silicon Valley, SPUR
Proposed Partners
26. Timeline
This project could be completed over
two academic years, from Winter 2019
to Fall 2020. Key milestones would
include:
Fall 2018: Finalization of project scope
and partners
Winter 2019: Identification of site,
schematic design
Spring 2019: 50% Design Development
Summer 2019: 100% Construction
Drawings
Fall 2019: Permitting
Winter 2019: Prefabrication
Spring 2020: Assembly
Summer 2020: Finish and Move-in
Fall 2020: Documentation and
Dissemination
27. Join the team.
If you are interested in co-creating this
prototype, please reach out.
Derek Ouyang
douyang1@stanford.edu
Lecturer, Stanford University
CEO, City Systems
Broken down prices within bars on graph to show where major savings are:
https://docs.google.com/spreadsheets/d/12oXmisuW8QaA095jSh_wjJzDCZmoF21mHV2DKjoUU-k/edit?usp=sharing
Original Average Cost of Construction based on Sonoma County data:
https://docs.google.com/spreadsheets/d/1CeeCDFOq_rsCtH9xn-hoygJfJTiHhrlMgsUWp5-qWNo/edit?usp=sharing
Based on proportions from this link, published by National Association of Home Builders:
http://eyeonhousing.org/2015/11/cost-of-constructing-a-single-family-home-in-2015-2/
Per aggregate data from HomeAdvisor.com (link below), panelized can be 10-20% cheaper than traditional methods
https://www.homeadvisor.com/cost/architects-and-engineers/build-a-house/#
Broken down prices within bars on graph to show where major savings are:
https://docs.google.com/spreadsheets/d/12oXmisuW8QaA095jSh_wjJzDCZmoF21mHV2DKjoUU-k/edit?usp=sharing
Original Average Cost of Construction based on Sonoma County data:
https://docs.google.com/spreadsheets/d/1CeeCDFOq_rsCtH9xn-hoygJfJTiHhrlMgsUWp5-qWNo/edit?usp=sharing
Based on proportions from this link, published by National Association of Home Builders:
http://eyeonhousing.org/2015/11/cost-of-constructing-a-single-family-home-in-2015-2/
Per aggregate data from HomeAdvisor.com (link below), panelized can be 10-20% cheaper than traditional methods
https://www.homeadvisor.com/cost/architects-and-engineers/build-a-house/#