Build a Custom ADU on Your Oregon City Property

Oregon City homeowners are increasingly turning to accessory dwelling units (ADUs) as a smart way to expand living space without moving.

A thoughtfully designed ADU can serve many purposes:

  • Housing for aging parents or adult children
  • A private guest house
  • A long-term rental unit
  • A home office or studio
  • Flexible space for future needs

As an experienced ADU builder serving Oregon City, Lamont Bros. helps homeowners navigate the entire process—from feasibility and design through permitting and construction.

Our goal is simple: create a comfortable, fully functional living space that fits naturally on your property and works for the long term.

Types of ADUs We Build in Oregon City

Every property is different. Our design-build team helps determine which type of ADU works best for your home and lot.

Detached ADUs (Backyard Cottages)

A detached ADU is a standalone structure built separately from your main home.

These backyard cottages provide the highest level of privacy and are often used for:

  • Rental units
  • Guest houses
  • Multigenerational housing
  • Private workspaces

Detached ADUs are one of the most popular options for Oregon City properties with available yard space.

Garage Conversion ADUs

A garage conversion ADU transforms an existing garage into a fully functional living space.

Because the structure already exists, garage conversions can sometimes:

  • Reduce structural work
  • Shorten construction timelines
  • Maximize existing square footage

We redesign the space to include proper insulation, ventilation, plumbing, and comfortable living layouts.

Basement ADUs

Many Oregon City homes have basements that can be converted into legal basement apartments or ADUs.

These projects typically include:

  • Separate exterior access
  • Egress windows for safety
  • Upgraded electrical and plumbing systems
  • Sound control and moisture management

A basement ADU is often the most efficient way to create a rental-ready living space within your existing home.

Attached ADUs

An attached ADU expands your existing home while maintaining a separate living area.

These additions are ideal for:

  • In-law suites
  • Long-term guests
  • Multigenerational living

Attached ADUs balance privacy with convenient proximity to the main home.

Why Oregon City Homeowners Build ADUs

Homeowners in Oregon City often build ADUs to create flexible living space while making better use of their property.

Whether used for rental income, multigenerational housing, or future needs, an ADU can provide both immediate functionality and long-term value.

 

Rental Income Potential

Many homeowners build ADUs as long-term rental units, creating an additional income stream.

Multigenerational Living

ADUs allow family members to live nearby while maintaining privacy and independence.

Increased Property Value

Properties with ADUs often become more desirable because they offer flexible housing options.

Future Flexibility

An ADU can adapt to changing needs over time—from guest housing to rental space to a private office.

Lamont Bros. Design & Construction

Oregon City | ADU Builds

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Start Planning Your Oregon City ADU

Our design-build team helps Oregon City homeowners plan accessory dwelling units (ADUs) that add flexibility, value, and long-term livability to their properties, from early feasibility questions through completed construction. 

When you schedule a consultation with Lamont Bros., you’re not committing to building an ADU. You’re simply starting a conversation about what might be possible on your property.

Your consultation is designed to help you:

  • Clarify your goals for building an ADU: whether for family, rental income, guest space, or aging in place
  • Explore potential ADU types for your property, including detached backyard cottages, garage conversions, or attached units
  • Understand Oregon City zoning considerations, permitting timelines, and feasibility for your lot
  • Discuss typical investment ranges for ADU projects in Oregon City and surrounding areas
  • Determine whether a design-build approach is the right fit for planning and constructing your ADU

Since 2008, our team has helped hundreds of Portland-area homeowners thoughtfully expand their homes through well-planned remodeling and construction projects. We focus on providing clear guidance early in the process so you can make confident decisions about your home, your property, and your investment.

Request a Consultation

Oregon City | ADU Builders

Frequently Asked Questions

Can I build an ADU on my property in Oregon City?

In many cases, yes. ADU eligibility depends on zoning rules, lot size, setbacks, and site conditions. A feasibility review helps determine what your property can support before design begins.

How much does it cost to build an ADU in Oregon City?

ADU costs vary based on factors such as size, site conditions, utilities, and finish selections. Detached ADUs typically cost more than conversions because they require new foundations and structures.

Is a detached ADU better than converting a garage?

Detached ADUs offer more privacy and flexibility, while garage conversions can be more cost-efficient by using an existing structure. The best option depends on your property and project goals.

Can I rent out an ADU?

 Many homeowners build ADUs specifically for long-term rental income. Local regulations can affect rental use, so it's important to review city requirements before building.

How long does it take to build an ADU in Oregon City?

Most ADU projects take several months from design through construction. The timeline depends on permitting, design complexity, and whether the project is a detached ADU, garage conversion, or basement conversion.

What size can an ADU be in Oregon City?

 ADU size limits are determined by local zoning rules and building regulations. Many ADUs range between 400 and 900 square feet, though the exact maximum depends on your lot and the type of ADU being built. 

Do ADUs require separate utilities?

 ADUs can either share utilities with the main home or have separate connections depending on the design and local requirements. During planning, your builder will determine the best approach for plumbing, electrical, and sewer connections. 

Will building an ADU increase my property value?

 In many cases, adding an ADU can increase property value by creating additional living space and potential rental income. Properties with well-designed ADUs are often more attractive to buyers looking for flexible housing options. 

Do ADUs require separate utilities?

Some ADUs share utilities with the main home, while others may install separate connections or meters. The decision often depends on project goals, site infrastructure, and local utility requirements. Proper planning ensures the ADU functions comfortably and efficiently.

How do I start building an ADU in Oregon City?

The first step to building an ADU in Oregon City is evaluating your property’s zoning allowances and site conditions. A design-build team like Lamont Bros. Design & Construction can help determine feasibility, estimate costs, and create a design that meets your goals. 

The Lamont Bros. Difference

Award Winning Craftsmanship

Lamont Bros. has earned recognition as a multi-award-winning Portland design-build firm, including the NARI Remodeler of the Year award and Houzz Best Service every year since 2016.

Client-Verified Excellence

Lamont Bros. maintains a 4.8-star average rating across Google, Houzz, and Yelp, reflecting consistent client satisfaction across hundreds of completed remodeling projects.

20 Years of Experience

Since 2008, Lamont Bros. has completed 850+ remodeling projects across the Portland metro area, including kitchens, bathrooms, additions, and ADUs in Portland, Beaverton, Lake Oswego, West Linn, and Oregon City.