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Jack Barnes Architect ADU Profiles

To learn more about this company, check out ADU Designer Profile: Jack Barnes Architect. For a more in-depth look, read Susan Moray’s ADU: Updating History in Ladd’sBarbara Gundle’s ADU: A 2-Story Garage Conversion, and Sharon Nielson, Keith Pitt, & Stephanie Mix’s ADU: A Miniature Mansion

ADU #1: Susan Moray’s ADU: Updating History in Ladd’s

  • Square Footage: 508
  • Year Built: 2013
  • Architect/Designer: Jack Barnes Architect, PC
  • Builder: Design Build Portland
  • Current Use: Short-term rental
  • Ballpark Cost: $110,000 plus some sweat equity

The Project: The goal for the project was to create a vacation rental that could eventually be used as a small residence for Susan if needed. This project involved adding on to an existing garage, but essentially was a new build. The old garage was protected from demolition due to its location in the Ladd’s Addition Historic District. Exterior walls were kept, but the roof and slab were almost fully rebuilt and upgraded for insulation, structural, and waterproofing reasons.

The Challenges: Initially we were excited to try building something 1-1/2 stories tall and with less of a traditional aesthetic, but working around the existing garage really limited us to a single story. This turned out to be a good constraint for the project, since the resulting design feels more open, bright, and airy than if we had crammed two floor levels into the 18-foot height limit. And despite the traditional exterior appearance, we were able to have a more playful interior with contemporary finishes and fixtures.

The Solutions:

  • We raised the floor level of the old garage to create the new bedroom, which means it is “two steps up” from the main living space (kitchen and living room). This creates a really elegant hierarchy of spaces with the kitchen/living being a bit taller than the bedroom/bath. Visitors to the cottage always remark on how nice it feels to have the bedroom and bath slightly separated from the living spaces, not just with walls or doors, but with a change in elevation.
  • We also strove for comfort & energy efficiency and were inspired by the Passivhaus standard, a rigorous green building approach. Some of the strategies we used included continuous exterior insulation, a heat exchanging ventilator (to provide fresh air), and high-performance windows. All of these things make it easier to keep in the warmth provided by the radiant floor system.
  • One feature the Owner really likes is the way we provided plenty of natural light in the ADU, but without compromising privacy for either the house or the ADU.


ADU #2: Grippi ADU

  • Square Footage: 561 square foot ADU over 435 square foot garage/studio
  • Year Built: 2014
  • Architect/Designer: Jack Barnes Architect, PC
  • Builder: Green Hammer
  • Current Use: Guest house, with plans to use as short-term rental, garage below used as photographer’s studio.
  • Ballpark Cost: $225,000

The Project: The homeowner wanted a space for his family to stay when visiting from out of state, with potential to use as an income property (e.g. short term rental). The ADU replaced an old garage, so it was important to keep a garage space as part of the project. This space needed to be flexible enough to use as a studio or workshop space, and would be accessible from the back yard of the main house.

The Challenges: The clients felt strongly about having tall ceilings for the garage space (ground floor). With an 18-foot height limit for the structure, this meant that the ADU (second floor) would be a tight fit. We accomplished this by designing broad shed dormers for the center portions of the roof, but I would like to have made the ADU portion a bit taller even if it meant a shorter garage/studio space.

The Solutions:

  • I like the way we were able to extend the ADU out over the garage entrance to play down the garage on the front facade.
  • We also had a lot of fun designing the entry stair at the rear of the ADU, which included a slatted screen to act as the guardrail while also providing some privacy between the ADU and the house.

ADU #3: Barbara Gundle’s ADU: A 2-Story Garage Conversion

  • Square Footage: 440
  • Year Built: 2015
  • Architect/Designer: Jack Barnes Architect, PC
  • Builder: Birdsmouth Construction
  • Current Use: Short-term rental
  • Ballpark Cost: $160,000

The Project: The project involved conversion of an unusual structure: a  garage having a 12’ x 20’ footprint, with a studio space above the garage. Changes to the structure required approval through a City design review process since the property is located in the Irvington Historic District.

The Challenges: Working within the old footprint of a two-story structure made it tough to connect the two levels with a staircase, and still have functional spaces left over. We opted for a prefabricated spiral staircase. While it does take up a lot of usable floor area, it is much more compact than a site-built stair (e.g. straight-run or L-shape).

The Solutions:

  • The client’s initial idea was to turn the upper floor into a bedroom and bathroom, but together we quickly realized that an “upside down” ADU made more sense, i.e. the existing top floor was the best pace for the main living spaces, since it would be brighter and more comfortable than the former garage space below.
  • So we kept the upper floor as a combined living & kitchen space with windows to the trees on three sides, and I’m really glad to see the top floor used in this way.
  • Conversely, the old garage below made more sense as a darker space for sleeping, but with the option to open up to a future landscaped area.

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.

2 comments on “Jack Barnes Architect ADU Profiles

  1. Michael
    March 19, 2016

    Can an ADU be built on a lot with an existing duplex? No existing other structures are on the lot besides the duplex.

    • linamenard
      April 7, 2016

      Michael, I believed the answer to your question about ADUs on lots with duplexes was no, so I checked in with fellow editors. Here’s Kol’s response: “This is one of the changes that is being discussed in the Residential Infill Advisory Group, but the current rules don’t allow it.” Please consider attending a meeting of the Residential Infill Advisory Group if you’d like to share your thoughts there!

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