Rainbow Valley Design & Construction

Rainbow Valley Design & Construction is an Oregon-based design-build company offering custom design and construction services for homes, remodels, additions, studios, and accessory dwelling units (ADUs). Founded in 1971 in Eugene, the company has developed into an established design-build firm with more than five decades of experience. Its ADU services focus on creating compact, functional spaces that blend naturally with the existing home and surrounding neighborhood.

An accessory dwelling unit — also referred to as a backyard cottage, granny flat, in-law suite, or secondary dwelling unit — is an additional living space located on the same property as a primary residence. Rainbow Valley approaches these projects as studios, backyard cottages, and ADUs, offering both pre-designed plans and custom design options.

What Rainbow Valley Offers Beyond Construction

Rainbow Valley operates using an integrated design-build model, meaning its design and construction services are handled by one coordinated team rather than separate architecture and general-contractor firms. The company says this approach streamlines communication, scheduling, and cost tracking from the early design stages through construction completion.

For small-cottage and ADU projects, Rainbow Valley’s professional designers focus on maximizing available space and functionality while making the new structure complement the existing home and neighborhood. Homeowners can choose from the company’s pre-designed plans or pursue a completely custom design based on their property and needs.

The company’s portfolio demonstrates experience with a variety of backyard cottage and ADU applications. For example, its Judy’s Cottage is a 768-square-foot backyard cottage designed and built for multigenerational living, while the Kelley ADU transformed an underutilized, steep backyard into a flexible living and guest space.

Rainbow Valley also emphasizes sustainability and long-term performance. Its broader design-build practice incorporates environmentally responsible approaches, and the company describes itself as one of Oregon’s leaders in sustainable design and construction. It also provides a five-year warranty on its work.

The company’s experience extends beyond ADUs to custom homes, remodels and additions, kitchens and bathrooms, and outdoor spaces, allowing homeowners to coordinate an ADU with other improvements to their property when needed.