Small Backyard Homes Initiative

Confronting rising housing costs and climate change.

The Institute for Sustainable Solutions is spearheading an initiative to make it easier and more affordable for Portland homeowners to construct a second house on their property—increasing housing options in a city with some of the fastest rising rents and lowest vacancy rates in the nation.

Called “accessory dwelling units” or ADUs, these small backyard homes can be used by family members or rented out to others in the community. They provide more affordable housing options while reducing pollutants that cause climate change.

Matthew Gebhardt, assistant professor of Urban Studies and Planning, and Yael Kidron, Ph.D. candidate in Urban Studies and Planning, conducted a survey of ADU owners and tenants in Portland. The survey was conducted as part of the Institute's Small Backyard Homes Project which is focused on encouraging ADU development for a more sustainable and equitable city. 

The City of Portland has been a national leader in ADU development, and the survey is the first of its kind—targeting not only ADU owners but those who live in ADUs as well.

Download the report with survey results.

The Institute is working with city agencies, architects, financial institutions, low-income housing providers, and others to develop a simple, affordable, ready-to-go solution for homeowners interested in building an ADU.

Interested in putting an ADU on your property? Join the ADU interest list here.

Our Small Backyard Homes Initiative is focused on:

  • Reducing construction costs (most Portland ADUs currently cost about $170,000)
  • Increasing financing options
  • Supporting systems to use ADUs as affordable housing 
  • Streamlining the processes for designing, financing, permitting, and constructing ADUs
  • Assuring there are enough qualified general contractors and builders 
  • Addressing the concerns and issues homeowners have about being landlords

Community benefits of ADUs

ADUs provide additional housing in existing urban spaces while retaining neighborhood characteristics. Their small size (typically 400-800 sq. ft.) makes them more affordable than standard size homes.

Specifically, ADUs offer:

  • a means of making a standard size house more affordable by providing rental income to the homeowner.
  • a way for aging family members to live near children or other relatives.
  • increased options for affordable housing providers.
  • an alternative or supplement to the development of large apartment buildings. 

Environmental benefits of ADUs

ADUs help reduce carbon dioxide and other pollutants that cause climate change by increasing urban density and requiring fewer natural resources to build and operate than a standard sized home. About 25 percent of greenhouse gas pollutants result from driving—ADUs reduce the need for driving because they increase housing options in urban areas where walking, biking, and public transit are more convenient. And because ADUs are generally smaller than typical single-family homes, they use fewer natural resources to build and less energy to heat and cool. 

ADUs in Portland: a Webinar on Survey Research of Owners and Tenants of Accessory Dwelling Units in Portland, Oregon - 7/31/2018

Next Steps

During 2016–17, the Institute for Sustainable Solutions is convening cross-sector groups that include PSU faculty and students to find ways to overcome obstacles to constructing ADUs in Portland. The Institute aims to test those solutions by assisting homeowners and others with the construction of 200 ADUs during 2017 and 2018. The ultimate goal is to create systems and practices that make it easier for people who want an ADU on their property to build them. 

In the News


The initiative has benefitted from the insights and suggestions of people from a wide spectrum of organizations, including: