Home Additions & ADU Services

Expanding your home can transform how you live. At Neil Kelly, we guide you through the full design/build process, combining expert planning, skilled craftsmanship, and attentive project management to bring your vision to life.

From adding a new room or extending your existing space to building an ADU for family or additional space, we create additions that are functional, beautiful, and seamlessly integrated with your home. Let’s explore the possibilities together.

SCHEDULE A CONSULTATION >

Our Approach to Home Additions

Expanding your home is about more than adding square footage—it’s about creating space that feels seamless, functional, and uniquely yours. From design through construction, our award-winning team ensures every detail blends beautifully with your existing home while adding lasting comfort and value.

We also offer a five-year warranty that supports your space long after our work is finished. Schedule a consultation or visit one of our design centers to learn more about Neil Kelly’s design/build difference.

Bedroom with large windows and a view of the trees outside.)

Custom Addition Design

Collaborate with our designers to plan an addition that matches your lifestyle, whether it’s more room for family, entertaining, or a private space.

Modern two-story home with blue siding and a warm wood entry accent.)

Second-Story Additions

Add vertical space with a thoughtfully designed second story that expands living areas while maintaining the character of your home.

Lakeside cottage with a detached hot tub and green shingle siding.)

Room Expansions & Bump-Outs

Enjoy more space where you need it most, like kitchens, living rooms, or bedrooms, with carefully integrated bump-outs or extensions.
 

Backyard AD with a glass door, patio seating, and a minimal landscaped path.)

Accessory Dwelling Units

Create a self-contained living space for family, guests, or rental opportunities with a custom-designed ADU that’s stylish and practical.

Bright sunlit great room with expansive glass walls and a view of the outdoors.)

Sunrooms & Specialty Spaces

Bring the outdoors in your home with sunrooms, home offices, or other custom spaces tailored to your needs.
 

Explore Our Home Addition & ADU Transformations

Discover the possibilities of expanding your home. Browse our gallery to see how thoughtful design and expert craftsmanship turn additions and ADUs into functional, beautiful spaces.

VIEW GALLERY >

Additions & ADU Tips & FAQs

Add Value to Your Home With an ADU

Creating a custom Accessory Dwelling Unit (ADU) with Neil Kelly is an experience that blends innovation and craftsmanship. From the initial consultation to the final touches, our team works closely with you to design and build a unique ADU that exceeds expectations.

If you have an addition or ADU project you would like to discuss with our team, you can connect with one of our consultants in the following areas:

– Portland, Oregon – Eugene, Oregon
– Bend, Oregon – Seattle, Washington

Additions & ADU FAQs

Have questions about additions or ADUs? Our team provides answers to common questions homeowners have about the remodeling process.

Depending on where you live, the requirements for an ADU include, but are not limited to:

  • Sleeping, kitchen, and bathroom facilities
  • At least one operable window or exterior door approved for emergency escape and rescue openings
  • You must be able to open the window or door from the inside
  • Heating controls are separate from the primary dwelling unit
  • Connection to water and sewer services

To ensure your ADU complies with your local laws and regulations, talk to our team.

It depends on the type of ADU you want to build, the type of property you have, the building regulations in your local area, and other factors.

The best way to learn specifics about project cost is to contact one of our designers about the project you have in mind.

In general, ADUs designed to suit an existing property or structure are going to be more functional for residents and create more resale value for homeowners. However, some municipalities in Oregon are offering plans that are pre-approved to streamline the permitting process, and plan sets are available from various sources. Your Neil Kelly Design Consultant can help you choose a starting point that meets your project vision and goals.

In many states, a building permit is required to build a new structure or convert attics, garages, or other spaces into a living space like an ADU. Depending on your project, you may also need electrical, plumbing, or mechanical permits.

The best way to find out specifics about ADU construction in your area is to speak with one of our designers.

In Oregon and Washington, you can rent out an ADU, but you must ensure it meets all local zoning regulations and building codes for long-term occupancy, not as a short-term rental (such as an Airbnb or VRBO).

Renting out an ADU involves being a landlord, and each city may have different requirements that must be met. It’s important to check your specific city's development code and regulations and verify that permits and licensing requirements are in place.

Yes, building an accessory dwelling unit will likely increase your property taxes in both Oregon and Washington because it adds value to your property.

However, the property tax is not applied to your entire home, and the exact amount depends on your local tax rules and the ADU’s size and features.

Zoning rules vary by city, but generally require:

  • The property is residentially zoned.
  • The ADU meets size limits (often 500–1,200 sq. ft.).
  • Adequate setbacks, height limits, and parking are observed.
  • Permits are obtained before construction.

For more information:

Oregon ADU zoning

Washington ADU zoning

No, you cannot build an ADU before your main house because ADUs are legally defined as a secondary living space to your primary residence. Most zoning codes require the primary residence to be established first.

Yes! It is possible to build an ADU on a historic property, but it may require meeting specific design standards or undergoing a Historic Resource Review process to ensure your new space is compatible with the historic context of your existing home.