ADU · Portland

ADU Construction in Portland, OR

The highest long-term ROI of any addition.

ADU-forward city where rain detailing and seismic retrofits go together.

ADUs are the fastest-growing residential category in 2026 for a reason: they pay for themselves. We match you with firms that build to code and to rent, detached, attached, or garage conversion, with the local ordinance know-how that makes or breaks the project.

Typical cost $50,000 – $250,000
Per sq ft $150–$300 / sq ft
Timeline 4 to 8 months
Resale ROI ~41% added appraisal value, plus $1,500–$2,500/mo rent
Cost note Detached 400–800 sq ft: $100k–$250k. Garage conversions: $50k–$120k. Avg build ~$180k.

Portland market

ADU in Portland: what the market looks like

Portland's pro-ADU policy and older housing stock make accessory units and seismic-aware additions the growth categories. Moisture detailing is everything in this climate.

Permits in Portland

Portland encourages ADUs with reduced fees; seismic and rain-screen detailing carry the technical weight, and a good Portland builder designs for both.

Portland conditions

Building adu for Portland conditions

Portland's lot rules, setbacks, and parking requirements decide what's buildable before any design starts, so the firms we match confirm zoning feasibility on your specific parcel first.

Our standard

What we require from adu construction firms in Portland

  • Detached, attached, and garage-conversion ADUs
  • Built to rent: separate metering and entrances
  • Local ADU ordinance and setback expertise
  • Income-property finish, built to rent well for years

ADU Construction in Portland, OR: your questions

What does adu construction cost in Portland, OR?

Portland's pro-ADU policy and older housing stock make accessory units and seismic-aware additions the growth categories. For adu construction specifically: Detached 400–800 sq ft: $100k–$250k. Garage conversions: $50k–$120k. Avg build ~$180k. National range: $50,000–$250,000. In Portland, OR, costs land toward the higher end of national ranges for urban markets. Use our cost estimator for a scope-adjusted figure.

How long does adu construction take in Portland, OR?

A typical adu construction project runs 4 to 8 months. In Portland, the permit timeline matters as much as the build window: Portland encourages ADUs with reduced fees; seismic and rain-screen detailing carry the technical weight, and a good Portland builder designs for both. The firms we match commit the completion date in writing.

What permits does adu construction require in Portland, OR?

Portland encourages ADUs with reduced fees; seismic and rain-screen detailing carry the technical weight, and a good Portland builder designs for both.

How do you match adu construction contractors in Portland, OR?

We vet remodeling firms in Portland before the first introduction: license verified, insurance confirmed, references called, complaint history reviewed. You describe the project, we send a short matched list of firms that work in Portland and specialize in adu construction. Free for homeowners.

Get matched for adu construction in Portland.

Tell us about your project. We hand you a short list of vetted local remodelers, free, and stay out of the rest. No phone-blasting, no pressure.