Touring a basement conversion ADU in Portland

Last Thursday, as a part of Design Week Portland, I had the chance to tour this basement conversion ADU (accessory dwelling unit) off NE Prescott:

It was pretty cool! From the outside, you’ll notice both sliding glass and French doors where garage doors used to be. This is because it’s a basement and garage conversion ADU.

In case you aren’t already aware, ADU is shorthand for adding a second living space (bed, bath, and kitchen) to a residential property. ADUs can be inside the existing structure or somewhere else on the property (space-permitting).

More generally, ADUs are neat because they open up a number of opportunities:

  1. In communities without new land to build on, ADUs can be cost-effective infill housing.
  2. ADUs make homeownership more attainable by adding cash-flow to cover the mortgage.
  3. For seniors wanting to downsize, ADUs can offer a “downsize in place” option that lets them stay within the community.

Here’s a pano of the immediate interior:

The developer, Kol Peterson, has been building and consulting on ADUs for almost a decade now through his company, Accessory Dwelling Strategies. He’s also written a book, Backdoor Revolution, that’s incredibly informative and information-dense. I’m already at page ~150.

As far as building an ADU in our house goes, I’ve already discovered what Kol identifies in the book as a classic regulation blocker:

(5) In addition to the parking spaces required in TDC 73.370 for the detached single-family dwelling, one paved on-site parking space shall be provided for the accessory dwelling unit and the space shall not be within five feet of a side or rear property line.

In short, we need a three car driveway in order to permit an ADU. But, we only have two slots and there’s no place to put a third. And, ironically, our neighbor can park six cars in their garage, driveway, and street just fine.

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