The Design


I’m familiar with living in small spaces from Hong Kong. My 550 sq ft apartment, although compact, had 2 bedrooms, combined living/dining room, a galley kitchen, and bathroom. The finish quality was high as the small area means it cost relatively little to use higher quality materials.

Here’s my former Hong Kong apartment:

Design Criteria

However a 200 sq ft garage is much smaller so I would have to come up with new ideas to fit in all the usual amenities: bathroom, cooktop, fridge, dishwasher, washing machine and so on.

One design requirement was no Murphy Bed: too much strapping and unstrapping the bedding, moving pillows, when stowing/unstowing.

I also wanted the ADU to be energy-efficient, so well insulated and air-tight, electric only/ no natural gas, and use rainwater for toilet flushing and laundry (I will discuss my rainwater system in another post), also solar roof and backup power.

First Design Attempt

My first design attempt was separate rooms – living, kitchen, bedroom, bathroom – squashed into the 200 sq ft area. I used the free online tool to create these plans.

There were some limitations with this design: no way to fit a Queen bed, it would be Double at most. Also it was doubtful the clearances in the bathroom would meet city code. (For example there must be 1’3″ clearance on each side of the center line of the toilet.)

Jack Barnes: Architect

I had met Jack on an ADU open home tour the previous year so got in touch and he agreed to come up with a design and to work through the city approvals. As I’m in a historic district there were complications around modifying a historic contributing structure.

His breakthrough idea was to locate the kitchen and bathroom on a 2 ft high platform with 3 steps leading up from the living area to the kitchen. The queen-sized bed would stow away under the platform creating a living space during the day, converting to a bedroom at night.

The Garage

My 1929 house, located in the Irvington Historic District in Portland, came with a small 18×11 ft. garage. It was no longer used as a garage and had been converted into a garden studio by a previous owner.

There were structural issues: the concrete slab was cracked, it was below grade and there was continual water infiltration resulting in dry rot in the mudsill and studs. The bump-out at the back of the garage, which had been added to provide storage cabinets, was open at the bottom resulting in a rat and invasive bamboo infiltration.

The garage, while nicely decorated, was going into rapid decline and it had little utility having no plumbing and only a rudimentary electrical feed.

The City wants more ADUs

Portland is facing a housing shortage and the city is waiving System Development Fees for ADU construction. This runs to typically around $15,000 for an ADU. This fee covers additional city public infrastructure for the increasing city population – parks, bike paths, water supply and so on.

I attended a weekend workshop, toured some Portland ADUs, and decided to convert my garage into an ADU.

I will use this blog to document this process.