Serving Clackamas County, OR
ADU Builders in Clackamas County
Gencon designs and builds accessory dwelling units across Clackamas County (detached cottages, attached suites, and rental-income ADUs) with permitting and land-use handled from concept to final walkthrough.
Free estimate: 503-825-0123An ADU adds a whole second dwelling to your property (rental income, a place for family, or flexible space) on a lot you already own. Gencon designs and builds accessory dwelling units across Clackamas County and handles the land-use and permitting maze from day one.
Types of ADUs we build
- Detached: a standalone cottage or backyard unit with its own entrance and yard
- Attached: a suite built onto or into the existing home
- Garage conversion: the budget path, reusing an existing structure
- Basement conversion: a legal apartment carved out of existing lower-level space
Related: Detached ADUs · Garage-to-ADU conversions
Can you build an ADU on your lot?
In most cases, yes. Under Oregon's HB 2001, every single-family lot in an urban residential zone may add one ADU, and as of September 3, 2024, ADUs are also allowed on many rural residential properties in Clackamas County. Units are capped in most cases at 900 square feet.
The details are where projects get stuck: setbacks are typically 5–10 ft on the sides and 15–25 ft front and rear, but hillside and corner lots vary, and detached units must match the primary home's materials, roof shape, and window styles to meet county design-compatibility standards. We run a feasibility check on your specific lot and zone before you spend a dollar on design.
Our ADU process
- Feasibility & land-use review: we confirm your lot qualifies and map the setbacks, size, and utility routing.
- Design: a unit that fits the site, your budget, and the county's design standards.
- Permitting: building and land-use permits pulled and managed with the county.
- Build: foundation through final finish, with utilities coordinated to the main house or street.
- Final walkthrough & inspections: a move-in- or rental-ready unit.
Cost and rental income
ADU cost depends heavily on type and size. A garage conversion that reuses an existing structure is the least expensive path; a detached, ground-up cottage with new foundation and utilities is the most. Many owners build to generate long-term rental income or to house family, and the added dwelling can lift the property's value.
Related: ADU cost in Clackamas County
Frequently asked questions
- How big can an ADU be in Clackamas County?
- In most cases up to 900 square feet. Exact limits can vary with your zone and lot, which we confirm during the feasibility review.
- Do I have to live on the property to build an ADU?
- Oregon removed the statewide owner-occupancy mandate for ADUs, so in most urban residential situations you don't have to live on-site, but local specifics can vary, so we confirm the rules for your address.
- Can I rent out my ADU?
- Yes, long-term rental is broadly allowed and is the most common use. Short-term (vacation) rental rules vary by jurisdiction, so we point you to the current local requirements.
- Is a garage conversion really cheaper than a detached ADU?
- Usually, yes. A conversion reuses the existing foundation, walls, and roof, so you're mainly paying to add insulation, utilities, egress, and finishes rather than building a structure from the ground up.
Our adu construction services
Detached ADUs
Gencon designs and builds detached ADUs and backyard cottages across Clackamas County, standalone units for rental income or family, with permitting and land-use handled end to end.
Garage ADU Conversions
Convert your garage into a legal, rental-ready ADU. Gencon handles garage-to-ADU conversions across Clackamas County: utilities, egress, and county permitting from start to finish.
Available across Clackamas County
We bring this service to homeowners throughout the county, including:
Planning a adu construction project?
Book a free, no-pressure consultation and estimate with our family-owned team.