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Victor & Kendra Duong’s ADU: Doubling Rental Opportunities

Editor’s note: this ADU is featured on the upcoming ADU Tour 
Duong ADUQuick Facts

  • Setting: urban
  • Neighborhood: Beaumont Wilshire, Portland, OR
  • Type: stand-alone detached unit (new construction)
  • Use: long-term rental
  • Square Footage: 400
  • Year Built: 2015
  • Owners: Kendra & Victor Duong
  • Designer: Kendra Duong (503-853-2006)
  • Builder: John Gray Design
  • Total Cost: $120,000

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.

Duong ADU & Main House

Duong ADU & Main House (notice the stagger to allow sunlight)

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.

Duong ADU at Twilight

Duong ADU at Twilight

“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.

Duong ADU Heat System

Duong ADU Apex 72 Heater & Steibel Eltron Tankless Water Heater


“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.

Duong ADU & Main House 2

Duong ADU & Main House Backyard

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.

Duong ADU Dining & Entry

Duong ADU Dining & Entry (notice transom windows)

“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.

Duong ADU Dining, Kitchen, Bathroom

Duong ADU Kitchen & Dining

“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

About linamenard

Hi. My name is Lina Menard and I'm a small house dweller, designer, blogger, and builder. I'm currently collecting ADU Case Studies for Through my company Niche Consulting LLC, I help people design and build the home (and life) of their dreams! I also tell my stories about simple living in small spaces - like a travel trailer, a yurt, a backyard cottage, and tiny houses on wheels - at Niche News.

5 comments on “Victor & Kendra Duong’s ADU: Doubling Rental Opportunities

  1. Pingback: Rambo Halpern’s ADU: An New Old-Fashioned Carriage House | Accessory Dwellings

  2. Pingback: Lisa Lonstron’s Other House: A Rooming House | Accessory Dwellings

  3. Larry Klein
    October 4, 2017

    It seems that unless one is an architect/contractor, the cost of $300/sq ft I see is WAY too high to hire others. At that price/sq ft, it is higher than buying a house plus land in most parts of the US. It also makes the ADU uneconomical. To build a 1000 sq foot adu is $300,000. To have a really good investment, you need to get $3,000/month in rent. Realistic in your area?

    • Martin John Brown
      October 5, 2017

      Hey Larry, thanks for your comment. I know that the costs of these things can be surprising, but I think some of your assumptions are off. First, I’m not sure that the only goal of the project is to be a “really good investment” that makes, for example, “$3000/month.” If you read the post and the whole site, you’ll see that money is just one of many reasons people build ADUs.

      Also, the relationship between costs and square footage is NOT linear for buildings like these. A lot of the cost comes from systems, permits, design, etc — things that have little to do with the square footage. You would pay for those even in a 10 sf building. An 800sf ADU does not cost twice what a 400sf ADU does. The figures that I’ve sometimes heard for residential construction in the US — like $125/sf — are probably based on 2000+sf houses that, well, just aren’t made terribly well.

      So, to make a long story short, a well-done ADU is a different creature than most American housing. Yeah, it’s more expensive per sf, but it’s also probably a better dwelling in a lot of ways. It can provide meaningful rental income, but it probably won’t be the basis of a fortune. I guess the focus of ADUs is “quality and connection” not “maximizing profit.” Check out the “research” area of our site to learn more. -Martin

  4. Tracy Justo
    February 17, 2020

    What wording did you use to advertise both home and ADU?
    thank you

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