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Types of Accessory Dwelling Units (ADUs)

Single-family ADUs are secondary housing units that are located on the same lot as a single-family home. These units are also sometimes referred to as granny flats, in-law suites or backyard cottages.

Some popular ADU types:

Junior ADU (JADU)
These are smaller units that are typically less than 500 square feet and are often created by converting a single room within the primary residence.
Attached ADU
These are units that are attached to the main house, often as an addition or a converted garage.
Detached ADU
These are stand-alone structures that are separate from the primary residence. They can be built on the same lot as the main house or on a separate lot.
Basement ADU
These are units that are located in the basement of the primary residence.
Garage ADU
These are units that are built above or within an existing garage.
Multi-family ADU
Sometimes referred to as a secondary suite, these ADUs are designed to be part of a larger multi-family residential building, such as an apartment complex or duplex.
Accessory dwelling unit exterior

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What We Do?

Our skilled structural engineers provide ADU engineering in Oregon City Projects with permit-ready deliverables coordinated for Oregon County Jurisdictions.

Structural Site
Inspections

Structural
Calculations

Structural
Plans

Structural Permit
Sets

Construction
Administration

  • We assess existing conditions for ADU scope in Oregon City Projects and document constraints relevant to Oregon County Jurisdictions approvals.
  • Our ADU calculations establish gravity and seismic demands for Oregon City Projects projects under Oregon County Jurisdictions review standards.
  • We prepare framing, foundation, and connection details for ADU projects in Oregon City Projects, formatted for Oregon County Jurisdictions plan check.
  • Each ADU package in Oregon City Projects includes the documentation and structural references needed by Oregon County Jurisdictions reviewers.
  • During ADU construction in Oregon City Projects, we provide scoped engineering responses coordinated to approved Oregon County Jurisdictions permit sets.