The Treehouse ADU


This custom designed sustainable ADU floats in the trees over a steeply sloping site, nestling into the trunks, branches, and canopy of the surrounding forest.

The story for this sustainable ADU starts with a writer, reader, and artist returning to Oregon after living on the east coast for the past few years. Her desire to be closer to family and closer to nature while downsizing her lifestyle led to the genesis of this design. The solution was creating an ADU addition to her family’s property in the SW Portland hills. The steeply sloping, wooded site was challenging but also inspiring as the design aims to integrate with both the existing house and the large fir trees that live on site. The simple ADU flows out from the main house, and floats over the steeply sloping land below. The south face is an entire wall of glass, sixteen feet across, that connects the interior great room to the branches and canopy of the forest. The deck offers the client a tranquil space to read, write, bird-watch and commune with nature. A cozy interior centers around a floating fireplace, creating a warm inviting sense of comfort and home.

Throughout the design we looked for ways to incorporate passive sustainable strategies as well as high performance technologies. After several discussions and iterations of the custom sustainable ADU design, we selected the best design to proceed into the final phase of detailed construction drawings. The final version has a roof overhang to shade the south-facing glass wall in summer while allowing winter light to wash the interior. The exterior walls and roof have an added layer of rigid insulation to create an extra tight envelope, efficiently keeping the interior warm in winter and cool in the summer. We are sourcing local, renewable and/or recycled materials whenever possible throughout the project. We have also elevated the structure on piers to minimize the disruption to the forest floor below.

More information on our ADU design services:

City of Portland Oregon ADU Resource Page:



Sam Sudy - Project Designer
Nick Mira - Project Architect


Portland, Oregon
SW Hills