512 ADU in SW Portland

Built smart for lasting value

512sqft ADU: Compact, Refined, and Cost-Efficient Living

This project is a showcase of our BuildSmart series, a line of thoughtfully refined, cost-efficient ADU designs. The 512 ADU is named for its 512-square-foot footprint, and this Southwest Portland build demonstrates just how much can be accomplished within that compact framework.

Although this particular site was a larger lot, the 512 is intentionally designed to fit comfortably on many of Portland’s classic 5,000-square-foot lots, making it a versatile choice for homeowners across the city. In this case, the ADU was created as a rental unit — a welcoming, light-filled one-bedroom, one-bath home that will provide steady rental income and long-term value for the family, while also offering a place for future generations to live.

The 512 ADU has been honed over six years of development and multiple builds, evolving into one of our most efficient and adaptable models. While this is the second 512 completed under the BuildSmart name, it represents the fourth or fifth iteration in its design evolution. Each version has contributed to the fine-tuning that makes this series so successful today.

Inside, the layout prioritizes comfort, daylight, and storage within an efficient footprint. The plan includes a full kitchen with a hood vent and micro-hood, a living and dining space with excellent natural light, laundry, and a bathroom designed with enough flexibility to include either a tub or a shower. With vaulted ceilings and careful window placement, the space feels open and airy despite its compact size.

The 512 is also designed for speed and efficiency on the permitting side. It can be rotated, mirrored, or flipped to fit a wide variety of lots, and because it has been successfully permitted multiple times already, the model benefits from a streamlined permitting path. It qualifies for the City of Portland’s ADU SDC waiver exemption program, making it even more accessible to homeowners.

Like all of our BuildSmart projects, this home is built to last. High-quality Milgard windows, durable materials, and Earth Advantage Platinum certification ensure long-term performance and comfort. Heating and cooling are handled by a highly efficient mini-split system, with balanced ventilation provided by an energy-recovery ventilator.

For homeowners, the 512 ADU offers an economical way to add a durable, beautiful, and high-value asset to their property — one that provides rental income today and flexibility for generations to come.

Other Examples of the 512: