Space efficient housing initiative

Past successes and future opportunities

From 2009 – 2012, a small, informal, mostly volunteer group of small home advocates helped stimulate the development of more space-efficient homes by….


  • Working with the planning bureau and Portland City Council to waive Systems Development Charges on Accessory Dwelling Units (ADUs) and increase the ADU size limit from 33% to 75% of the primary dwelling or 800 sf, whatever is smaller
  • Incorporating home size into Oregon’s Reach Building Code so building shell requirements will adjust inversely with home size
  • Working with EarthAdvantage to quadruple the number of points granted to space-efficient homes in their proprietary ratings system
  • Working with Energy Trust of Oregon to allow ADUs to receive energy incentives previously available only to primary residences


  • Publishing Oregon DEQ studies documenting quantitative, life cycle environmental benefits of smaller and attached homes compared with other green building practices
  • Documenting the widespread existence of unpermitted ADUs in the City of Portland that most likely outnumber legal ADUs by at least a 3:1 margin
  • Creating a database of local ADU ordinances across Oregon


  • Producing a report providing guidance on consistent valuation of ADUs that will be published in the upcoming Oct/Nov issue of the peer-reviewed Appraisal Journal
  • Preparing a Guide for Appraising ADUs that has already been instrumental in the successful refinancing of a house + ADU in Portland

Education, Outreach & Events

  • Launching, a one-stop source of information about ADU’s, granny flats, backyard cottages, in-law units, accessory dwelling units.  The site also serves as a repository for images, plans, and the stories behind successfully completed projects.
  • Organizing and leading 4 tiny home bike tours, each one featuring different homes and attended by 100+ cyclists
  • Teaching quarterly full-day classes on the design, permitting and construction process for ADUs
  • Highlighting ‘pocket neighborhoods’, ADUs, homes-on-wheels, and other space-efficient housing models in local media including the Oregonian, Portland Tribune, the DJC, and OPB’s Think Out Loud.
  • Presenting environmental findings about the benefits of smaller homes to Metro, Energy Trust of Oregon, Earth Advantage, AARP, City of Eugene, Central Oregon Builder’s Association, City of Portland, Ecovative Conference, and others.  Presentations with live audio are also available at DEQ’s website.
  • Organizing a first ever summit on space-efficient housing

Future Space-Efficient Housing Work


  • Advocate for local governments to scale residential SDCs based on home size or reduce/waive SDCs on ADUs.  Both Portland and Eugene have committed staff time to explore scaled SDCs in the coming year.
  • Compile and disseminate model codes for pocket neighborhoods, ADUs and other zoning/building regulations that support space-efficient housing types
  • Work with Salem (Oregon’s largest city that prohibits ADUs) to adopt ADUs into its zoning code.
  • Participate in Portland’s comprehensive plan process and subsequent zoning code update to adopt code changes supportive of space efficient housing.  Target other cities going through code amendment processes to include provisions supportive of space-efficient housing.
  • Advocate for home size to be given appropriate weight in LEED Residential and other environmental ratings systems
  • Collaborate with affordable housing organizations, AARP, and other groups with overlapping interests in creating smaller, more affordable, and more accessible housing options
  • Explore density bonuses contingent on unit size in conjunction with pocket neighborhood zoning
  • Create ADU design competitions resulting in pre-approved ADU designs
  • Craft incentives for “accessible” ADUs


  • Collaborate with PSU or other research institution to study the impact demographic trends will have on housing needs, especially in growing cities (ie. Portland, Salem, Eugene)
  • Research how ADUs are being used in practice
  • Study the potential of ADUs to help meet housing growth projections for the Metro area


  • Work with local lenders (and perhaps governments) to create and market mortgage products that work well for financing ADUs
  • Produce a financing fact sheet for ADU-friendly mortgage lenders


  • Produce an Annie Leonard-style video that summarizes the environmental benefits of smaller homes in a fun, concise and accessible way
  • Explore the possibility of a Street of Small Homes event and tour in conjunction with the Homebuilder Association of Portland and/or Office of Planning and Sustainability
  • Organize more bike tours; keep adding projects to; continue teaching and expand ADU classes for homeowners; and hold a follow-up space efficient housing summit.
  • Extend outreach activities into Washington State and beyond Oregon’s Willamette Valley

Do you want to help?