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Editor’s note: this ADU is featured on the upcoming ADU Tour
Kendra and Victor Duong, a wife and husband architecture team, have always dreamed of one day designing their own space. A number of factors convinced them that the time was right. First, Portland’s System Development Charge Waiver was set to expire and they wanted to take advantage of the savings. Second, their friend John Gray was starting his own design/build business and was interested in partnering with them for the construction of the ADU. Finally, they wanted to invest in an additional rental property.
Victor and Kendra owned a rental house in Portland and they had a down-payment ready to purchase another investment property. However, the housing market was so tight they could not find an appropriate property. Instead they devoted the same amount of cash that would have gone into another property into building an ADU in the backyard of their existing rental property. (Check out Options for ADU Owners: Rent One, Both, or Neither.)
Portland is one of the few cities that allows ADU owners to rent out both the primary dwelling and the ADU, so Kendra and Victor took advantage of this opportunity. (For another example of homeowners doing this, take a peek at Rex Burkholder and Lydia Rich’s ADU: Own Two, Rent Both.) As they began designing their own ADU, they focused on several factors: affordable housing considerations, energy efficiency, and rental investment experience.
Between them, Victor and Kendra have many years of experience with affordable multi-family housing, market-rate multi-family housing, and high end design/build. Both are also LEED accredited professionals.
“We knew based on our housing experience, we could build our own unit within a realistic budget while maintaining sensible design aesthetics.” –Kendra and Victor Duong
Green features they incorporated are a fully insulated slab, roof assembly with an R-value of 49, insulated headers, and windows with a U-value of 0.26. There’s also a briefcase sized tankless water heater, a ceiling fan for air movement, a dual-flush toilet, and an energy-efficient washer and dryer.
Another green feature is that the ADU was outfitted almost entirely with LED lighting. Though concerned about photometric output, the Duongs were pleasantly surprised the LED lamps produced more than adequate lighting coverage.
“The beauty of these new LED fixtures is that they fit inside a standard 4” electrical box giving you more placement options and significantly simplifying installation costs. The fixture is also dimmable and rated for indoor or outdoor use.” –Victor Duong
For heating, Kendra and Victor did not use a mini-split system (sometimes referred to a ductless heat pump) or traditional electric base board heaters often found in ADUs. Instead, the Duongs used Cadets new Apex 72 heating system.
“This product was so new, we did not have any examples of it being used in a real project. This wall heater is designed to be mounted above head height saving precious floor space and increasing efficiency. It saved thousands of dollars compared to the cost of a ductless heat pump and simplified installation.” -Kendra and Victor Duong
For cooling, the Duongs relied on their LEED experience to integrate passive cooling design techniques such as good insulation, operable windows mounted up high (to encourage stack ventilation), and tall ceilings, to offset the need for active cooling in the form of air conditioning.
The ADU is placed on the west side of the property offset from the main house. The staggered layout allows uninterrupted sunlight from the south to reach the ADU. It also creates outdoor zones for both buildings. Offsetting the ADU also simplified utility hook ups for water, sewage, and electrical service.
Current zoning code requires that a detached ADU match the look of the primary dwelling. A plan review comment asked the Duongs to explain the transom windows on the ADU that did not match windows on the main house.
“We explained that the taller plate height in the ADU required taller windows for a more proportional façade language.” -Kendra Duong
For the interior space, the Duongs utilized quite a number of smart design decisions that allowed the ADU to feel larger than 400 square feet.
“We increased ceilings to 14 feet. Tall windows with transoms allow lot of natural light that helps the small space feel less confined. Double glass doors, when fully open, extend the perception of livable space onto the patio area. We added operable square windows up high to allow flexible furniture placement.“ -Kendra and Victor Duong
The Duongs also included similar trim details as the main house and included picture rails commonly found in older homes. A relite mounted high in the main space made of twin wall polycarbonate is a unique point of interest. For storage, the tall walls allowed a design opportunity for an overhead ledge that wraps two sides of the bathroom. Kendra selected her own tile, fixtures, hardware, and cabinets. She cut cost by using remnants for the quartz countertop. A lot of thought went into the kitchen design as well.
“We set the kitchen into an alcove to help it feel like it was along-side the main space rather than projecting into it. We were inspired by the simplicity of European kitchen designs and scaled down appliances. For example, we used a 2 burner cooktop instead of a 4 burner slide-in stove. The refrigerator and sink are 24” wide, and the overhead microwave doubles as an exhaust while saving precious counter space.” – Kendra and Victor Duong
Overall, the Duongs feel that the ADU has added to the neighborhood culture.
“It’s definitely an excuse to strike up a conversation. An ADU is less threatening than a McMansion to some of the neighbors and the scale is compatible with the existing homes. The ADU tenant felt welcomed and immediately interacted with main house tenants and the neighborhood.” –Victor Duong
Victor says he was surprised to discover that they are part of a greater movement.
“It’s a fraternity. We’ve had other ADU owners come up during the build just to say hi and welcome us. It’s neat to be part of this.” –Victor Duong
So what advice does Kendra have for homeowners considering creating an ADU on their own property?
“If you want to take advantage of the SDC waiver, start your project as soon as possible because you don’t want to be rushed. ” – Kendra Duong