ADUs are one of the most useful additions you can make to a Portland-area property. They produce rental income, house aging parents or adult kids, work as a high-quality home office, or boost resale value — sometimes all of the above.
Types of ADUs we build
- Detached new construction. A standalone small home, usually 400–900 sq ft, in the backyard.
- Garage conversions. Turning an existing garage into a full ADU (kitchen, bath, separate entry).
- Attached ADUs. Built off the side or back of the main house with a separate entrance.
- Internal ADUs. Carved out of an existing basement or upper floor with a private entry.
Portland ADU rules
Portland and most surrounding jurisdictions allow ADUs by right on most residential lots, but the rules vary on size limits, parking, owner-occupancy, height, and setbacks. We work with these codes regularly. We’ll tell you what’s allowable on your specific lot before we start designing.
What an ADU usually costs
Detached new-construction ADUs in the Portland market typically run $250K–$450K depending on size, finish, and site conditions. Garage conversions are usually $100K–$200K. SDC (system development charge) fees are a real budget line and vary by jurisdiction; we’ll account for them in your estimate.