★ ADU Contractor — Portland, OR

Portland ADU Construction: Maximizing Your Property Value

Mighty ADU Company builds high-performance Accessory Dwelling Units in Portland, OR, adding functional space and increasing equity.

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ADU Contractor Professionals

Mighty ADU Company

Portland, OR

Building an ADU in Portland requires a deep understanding of local zoning codes, like the R2.5 or R5 residential zones, and the specific challenges of our Pacific Northwest climate. We don't just build structures; we craft durable, energy-efficient living spaces designed to withstand Portland's wet winters and maximize natural light. Our process begins with a detailed site assessment, considering factors like existing utility access, tree protection requirements, and soil conditions common in areas like the West Hills or East Portland. We integrate advanced moisture management techniques, such as proper flashing details and rainscreen systems, to ensure longevity. Every ADU we build is engineered for optimal performance, providing a valuable asset that stands the test of time and local conditions.

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What We Handle in Portland

Attached ADU in Portland
01

Attached ADU

An attached ADU is a secondary dwelling unit built directly onto your existing Portland home, sharing at least one common wall. This option allows for efficient use of existing infrastructure and can often simplify permitting compared to detached structures.

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Detached ADU in Portland
02

Detached ADU

A detached ADU is a standalone structure on your property, separate from the main house, offering independent living space. This option provides maximum privacy and design flexibility, creating a distinct new dwelling.

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Garage Conversion in Portland
03

Garage Conversion

A garage conversion transforms an existing garage structure into a fully functional, habitable living space, often including plumbing, electrical, and insulation upgrades. This process unlocks significant property value and provides flexible living options without expanding your home's footprint.

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ADU Permitting in Portland
04

ADU Permitting

We manage the entire ADU permitting process in Portland, from initial application submission to final permit issuance. This ensures your project complies with all local zoning and building codes, avoiding costly delays.

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ADU Design in Portland
05

ADU Design

ADU Design involves creating detailed architectural plans, structural drawings, and material specifications for your Accessory Dwelling Unit. This comprehensive design package ensures your ADU is code-compliant, functional, and aesthetically integrated with your existing property.

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ADU Engineering in Portland
06

ADU Engineering

ADU engineering provides the structural and civil calculations needed for your Accessory Dwelling Unit's foundation, framing, and utility connections. This ensures your ADU is built safely, to code, and withstands Portland's specific environmental conditions.

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ADU Financing in Portland
07

ADU Financing

We connect Portland homeowners with tailored financing solutions for their Accessory Dwelling Unit projects, covering everything from design to construction. Securing the right funding ensures your ADU build progresses smoothly without unexpected financial hurdles.

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ADU Construction Management in Portland
08

ADU Construction Management

ADU Construction Management involves overseeing every aspect of your Accessory Dwelling Unit build, from permitting through final inspection, ensuring adherence to design and budget. This structured oversight keeps your project on schedule and within financial parameters, minimizing stress and unexpected complications.

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Junior ADU (JADU) in Portland
09

Junior ADU (JADU)

A Junior ADU (JADU) is an interior conversion of existing living space, typically a bedroom or den, into a self-contained unit with a kitchen, bathroom, and separate entrance. This creates an affordable, compact living solution that can generate rental income or house family members within your current home's footprint.

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ADU Site Assessment in Portland
10

ADU Site Assessment

Our ADU Site Assessment service provides a detailed analysis of your property's suitability for an Accessory Dwelling Unit, including zoning, utility access, and buildable area. This foundational step identifies potential challenges and opportunities, giving you a clear path forward for your ADU project.

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Portland's Local ADU Contractor Experts

Mighty ADU Company is proud to serve Portland, OR and the surrounding communities. Our reputation is built on honest work, clear communication, and results that hold up over time.

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Frequently Asked Questions

The typical timeline for building an ADU in Portland, from initial design to final occupancy, ranges from 8 to 14 months. This includes 3-6 months for design and permitting with the Portland Bureau of Development Services (BDS), followed by 5-8 months for construction. Factors like site complexity, specific design choices, and the current BDS review queue can influence this duration. We work to streamline the permitting phase by submitting complete, accurate plans from the outset, which helps avoid delays.
The cost to build an ADU in Portland, Oregon, generally ranges from $200,000 to $400,000, depending on size, finishes, and site preparation needs. This includes design fees, permitting costs, utility connections, and construction. For example, a detached 600 sq ft unit with standard finishes might be at the lower end, while a larger, custom-designed unit with high-end materials and complex utility trenching could be at the higher end. We provide a detailed cost breakdown after a thorough site assessment and design consultation.
Portland's zoning requirements for ADUs are quite favorable, allowing one ADU on any lot with a single-family home in residential zones. Key regulations include a maximum ADU size of 800 square feet or 75% of the primary dwelling's habitable space (whichever is smaller), and specific setback requirements that vary by zone. There are also height restrictions, typically limiting ADUs to 20 feet or the height of the primary structure. We navigate these specific codes, ensuring your project meets all city and county regulations.
ADUs in Portland typically do not require separate utility connections for water, sewer, and electricity, as they can often tie into the existing services of the primary dwelling. However, a separate electrical sub-panel is usually installed for the ADU, and sometimes a separate water meter is desired for rental purposes. Gas lines, if applicable, can also be extended from the main house. We assess your existing utility infrastructure during the initial site visit to determine the most efficient and cost-effective connection strategy.
For an ADU in Portland's climate, a poured concrete slab-on-grade foundation or a crawl space foundation with stem walls are both common and effective options. A slab-on-grade offers excellent thermal mass and can be more cost-effective, especially on level sites, but requires careful sub-grade preparation for drainage. A crawl space provides easier access for future utility work and can better accommodate sloping lots, while also allowing for robust insulation against moisture. We evaluate your specific site's soil conditions and drainage patterns to recommend the optimal foundation type for long-term stability and moisture control.

Proudly Serving Portland and the Surrounding Area

From Portland to the surrounding communities, we bring the same level of care and craftsmanship to every job — whether it's a quick repair or a full project.

Unlock Your Property's Potential. Start Your ADU Journey.

Schedule a free site consultation to explore your options and receive a preliminary project assessment.

Get Your Free Quote 503-608-4664