Backdoor Revolution-The Definitive Guide to ADU Development

Table of Contents




Part I: The Homeowner’s Guide to ADU Development


1) What Is an ADU?

Defining an ADU

Other Terms Used for ADUs

What’s in a Housing Unit?

Structural Forms of ADUs

The Multitude of Benefits of ADUs




Policy Goals

Terms You’ll Find in This Book

2) Timeline to Design and Build

Design and Permitting Process

Construction Process

3) Financing

How ADUs Build Wealth for Their Owners

ADUs as an Investment

Reducing Mortgage Payments

Breaking Even

Return on Investment

Paying Off the ADU

Financing an ADU

Cash Savings or Other Liquid Assets

Home Equity Lines of Credit

First Mortgage Cash-Out Refinance

Family-and-Friends Loans

Nonsecured Loans and Credit Cards

Renovation Loans

Construction Loans

4) Costs and Management of Development

What ADUs Cost to Build

The Costs of Development for Your Locale

Fixed Costs: Small Is Expensive

What Type of ADU to Build

Detached New Construction

Conversion of Preexisting Structures

Garage Conversions

Basement Conversions

Internal ADU Conversions


Large Variables That Drive Costs of Construction

Designer and Builder

Developer, General Contractor, Builder

Become the General Contractor

Use a General Contractor for the Weathertight Shell; and Become the General Contractor for the Finish Work

Use a General Contractor for the Entire ADU

Defraying Development Costs through Sweat Equity

Level of Finish

Salvaging Finish Materials

5) Design Principles

Small-Space Design Principles for ADUs

Design Principles for Detached ADUs

ADU Design Tips and Tricks

Technical Issues in Basement ADUs

6) Income Models

Common Models for ADU Ownership

Market-Rate Rentals

Short-Term Rentals

Or Do Not Rent It

The Social Relationship of the Residents

Fledgling Development Models

ADUs as Condos


Part II: The Professional’s Guide to ADU Development


7) What Is Distinctive about Developing and Inducing ADUs

Amateur Homeowner Developers

Asynchronous Development

Faith in Government

The Challenge of Financing ADUs

Small Business Infrastructure

Flexible Use

8) Zoning Barriers

Poison-Pill Regulations

Owner-Occupancy Requirement

Off-Street Parking Requirements

Conditional Use

Prohibitively Restrictive Development Regulations

Property Line Setbacks

Size Limits on ADUs

Minimum Lot Sizes

Structural Forms

Sewer or Water Connections, Development Fee Costs

9) Impacts on a City

Matching Housing Demographics with Housing Options

ADUs as Affordable Housing

Impact on Neighborhood Character

Parking Impacts

Space Efficiency and Location Efficiency

The Presence of Informal ADUs

The Cottage Industry Economics of ADUs

10) Case Studies of Advancing ADUs in Cities

Portland, Oregon

ADU History

Political Support



Urban Growth Boundary

Use Provisions

System Development Charge Waiver

Permitting Office Transparency

By-Right Development

Flexible Development Regulations

Advocacy and Educational Entrepreneurship

Vancouver, British Columbia


Political Support


Urban Growth Boundary


By-Right Development

Use Provisions

Development Regulations

Economics and Financing

Austin, Texas

Santa Cruz, California

11) A Pathway for Planners and Advocates toward More Permitted Development

Affordable Rental Housing Crunch

Dominance of Single-Family Residential Zoning

Political Leadership

Regulatory Steps to Induce ADUs

Attached First, Then Detached

Chipping Away at the Poison-Pill Regulations

Keeping Administrative Fees at Bay

Program Guides in Plain English

Incentives to Build ADUs

Metrics of ADU Development Progress

Practical Roles for Advocates

When Financing Options Come to Fruition

Challenging the Flawed History of Single-Family Zoning

Programs That Have Not Worked

Legalizing Informal ADUs

Promoting ADUs without Creating Suitable Development Conditions

Tethering ADUs to Affordable or Senior Housing Programs

12) Civil Disobedience and Accessory Dwellings

The Homeowner’s Perspective

Work-Arounds and Loopholes

Alternatives to ADUs

Detached Bedrooms and Other Accessory Structures

Basement Living Space and Other Carve-Out In-Law Suites

Nonhabitable Accessory Structures

Camping in Temporary Dwellings

Tiny Houses on Wheels

Mobile Dwellings: RVs, Vans, House Trucks, and Travel Trailers

Yurts and Tents

Tree Houses

Other Types of Small Housing

Building Beautiful Is Illegal


Appendix 1: Administrative Aspects of Ownership: How Utilities, Insurance, Appraisals, and Property Taxation Work

Appendix 2: History of ADUs

Appendix 3: Synonyms for ADUs

Appendix 4: Informal ADU Studies

Appendix 5: ADU Model Code

About the Author


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