Backdoor Revolution-The Definitive Guide to ADU Development


Author Kol Peterson, an accessory dwelling units (ADU) expert based in Portland, Oregon, recently released the book Backdoor Revolution-The Definitive Guide to ADU Development as a guide for planners, ADU advocates, and homeowners who aspire to build ADUs.

ADUs are poised to present the most viable stepping-stone solution for cities that are experiencing a housing crisis and exploring how to increase housing opportunities within their single-family residential zones, Peterson says in his Q&As about the book.

Peterson explains that ADUs are going to become very mainstream in the next two to five years, starting with California, but ultimately spreading quickly to many major cities in the US, including in Colorado, New England, North Carolina, and the DC Metro area.

The author is an ADU expert who has helped catalyze the exponential growth of ADUs in Portland over the last decade. He and his wife also live in an ADU that he developed in 2011. He is the owner of Caravan- The Tiny House Hotel, the first tiny house hotel in the world, and organizer of Portland’s popular ADU Tour. 


Backdoor Revolution serves two distinct audiences by design. ADUs are currently a rare housing form, and it was important to get both professional readers (ie. city planners, advocates) and homeowner developers on the same page. The book is available at

This first half of book serves as an in-depth, detailed guide to the process of designing and building an ADU. It covers costs, financing, permitting, ADU design, rental models, step-by-step guidance, and more. It is written primarily for homeowners who want to develop an ADU on their property. The second half of the book dives into larger issues that have kept ADUs from taking off in most US cities till now. It provides case studies and a synthesis of research about ADUs. It will help city planners and ADU advocates to increase the number of ADUs in their jurisdiction.

Special design considerations for ADUs

Peterson writes that building an ADU requires thinking three steps ahead. Backdoor Revolution will get homeowners thinking five steps ahead. This kind of advanced planning can really pay off, but it's impossible to plan like this without knowing what you're getting into.


ADUs are always accessory to a primary house. They're commonly urban infill. And, they're small and oftentimes bound by tight setback and height limitations.  Those three features make ADU design specialized, and arguably more challenging than designing a conventional larger home. There is overlap with tiny house design, boat design, and small house design generally, but many of the concepts are intrinsic solely to ADU design.

He points out that one overlooked concept that is the need for long-term storage: both interior and exterior. While it is convenient to simply not add in extra storage because it can take up precious square footage, it is critical to do so. Those who do not have sufficient storage ultimately regret it.

Bear in mind that instead of a single household on a given property, there may now be two. Both households need to store bikes, canoes, luggage and other seasonal items.

If the garage is going to be converted to ADU, the owners should consider adding a shed. It may make sense to incorporate the shed into the site plan for the ADU, to ensure that there is good flow on the property. If the shed is going to have a concrete foundation, then it would make sense to take care of the excavation and concrete work at the same time as the ADU. This will cost more, so the homeowner will need to apply for a slightly larger loan.

For more information on the book, visit

Published in February 2018

Print Friendly and PDF Email this page