Updates on our Small Backyard Homes Initiative

ADUs on display on the PSU campus

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.  (ADUs can also take the form of an internal apartment created by remodeling a part of a private home.  ISS is focused primarily on detached ADUs for the first phase of this project.)

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.

During 2018, participants in ISS’s Small Backyard Homes project will be releasing important research results and launching pilot projects.

Here are some upcoming highlights:

January 2018: Release of ISS’s survey of ADU owners and tenants

ISS commissioned Assistant Professor of Urban Studies and Planning Matthew Gebhardt and PhD student Yael Kidron to carry out a new and more comprehensive survey of ADU owners and their tenants in the city of Portland. This survey updates and supplements a survey carried out several years ago by the Oregon Department of Environmental Quality and its results are hotly anticipated by stakeholders as a gauge to measure the effects of ADUs on the region’s housing picture.  

Continuing 2018: Updated Geographic Information Systems (GIS) analysis of potential ADU sites in Portland

ISS commissioned GIS research on potential ADU sites by Sachi Arakawa, a graduate student in PSU’s Master of Urban and Regional Planning program. Sachi produced several sets of maps visualizing the spatial and temporal distribution of permitted ADUs in Portland since the 1990's and ran multiple site suitability analyses, taking into account various factors that prohibit, limit, or make more desirable the construction of detached ADUs. The result of these analyses was a set of maps showing the amount of residential taxlots in the city that are eligible for ADU development. During 2018, additional GIS analyses of ADU sites, as well as those of built ADUs, may be released.

Winter/Spring 2018:  Release of ISS’s Commissioned Market Analysis of ADUs

ISS commissioned an ADU market analysis with the Northwest Economic Research Center at Portland State University. Among other things, the research should provide an indication ADU's affordability including the impact of the City’s current policy of waiving about $15,000 in system development charges. The City Council will be considering whether to renew or terminate the SDC, which expires on July 1, 2018.

Spring-Summer 2018 (Tentative): Launch of ADU Concierge Services System by Enhabit

Enhabit, a nonprofit partner of ISS, is pursuing support to develop a suite of online resources, in-person assistance, and committed partners to help homeowners and others realize the benefits and impact of accelerating ADU adoption.  

The system of services would:

  • (a) Help homeowners make informed decisions about whether to build an ADU;
  • (b) Connect them to financing and services that will help them succeed if they decide to proceed;
  • (c) Engage vetted contractors and optional proven designs to manage costs and a facilitated construction process;
  • (d) Provide information and connections to potential incentives (from the public sector and other partners) that will encourage them to rent their ADU to households of modest means; and
  • (e) Provide information and incentives that will encourage them to incorporate sustainability features in their ADU and in the primary home.

Summer/Fall 2018:  Construction of Lower Cost Prototype ADUs

During 2017, ISS commissioned the students and faculty at the Center for Public Interest Design at Portland State University to develop prototypes for lower cost detached accessory dwelling units. Construction drawings for five prototypes are being developed, in consultation with contractors who would specialize in each prototype. The goal is to have three of the prototypes under construction by the second half of 2018.

2018:  Field Testing of New ADU Financing Product

Until now, most ADUs are financed by home equity lines of credit, mortgage refinancing or savings. This limits the opportunities for many people to build an ADU. ISS has been working with nonprofit and for-profit financial institutions to test the feasibility of financing that is based upon, or at least takes into account, the rent that can be generated from an ADU. The partners are currently exploring partners willing to provide additional at-risk capital during this pilot phase.