ADU Lessons from the East Bay of California

Over the holidays, I was fortunate enough to spend a couple of weeks in the East Bay area of California. The East Bay area, primarily Oakland and Berkeley, is overflowing with current ADU activity that makes it a place with fascinating sites, organizations and people who can help interpret what I am seeing. 

So, here’s a brief sketch of the people I met and the things I saw and learned from my winter work-cation. 

My first day trip involved a guided tour of some mobile dwelling encampments in Oakland by Adam Garret Clark, who is involved personally and professionally in this movement. I wanted to check this stuff out in Oakland in particular because the city is pioneering a new zoning standard called Vehicular Residential Facilities (starting on p.76), which I am fascinated by. 

Oakland is ground zero for a range of informal and formal housing solutions. We visited a sanctioned ‘safe parking program’, an unsanctioned RV park on a commercial property, unsanctioned encampments of RVs in various places in town, a sanctioned encampment of dwelling pods, and some informal squatter camps on residential properties. 

A private, unsanctioned RV park with both travel trailers and vans with long term renters

A tour of an unsanctioned encampment along Wood Street under I-80 in Oakland.

A sprawling complex of tents and trailers - the informal solution to housing for those who can not otherwise afford to live in Oakland or the greater Bay Area.

A City sanctioned and funded new development of dwelling pods at 2nd and E12th

A mobile laundry and shower unit used by unhoused populations in Oakland

The next day, in stark contrast to the encampment tour, I walked through an expensive neighborhood of Berkeley called Claremont, with Berkeley resident, Greg San Martin. I checked out Greg’s home, which will hopefully soon have multiple internal and detached ADUs.

Of course, ADU development costs a LOT of money in the Bay Area, so Greg probably won’t be able to afford to do too much of that work till lenders are able to provide more creative loan products to help homeowners like him to build. That said, in the four years since I last saw Greg’s house, ADUs have been built on three sides of Greg’s house, which he and I both applaud.  

We discussed how the very strict rental protections in Berkeley deters some homeowners from considering building ADUs for rent. Carve out exemptions to landlord tenant regulations should generally be afforded to owner-occupied rental properties of any sort, so as to not accidentally stymy homeowners from adding more middle housing units to their property due to their increased wariness of becoming landlords in the face of overtly tenant-oriented policies such as found in Berkeley (and Portland, where I live).

Next, I met with Deb Sanderson, a former city planner in Berkeley and an active member of the Casita Coalition, a Californian ADU organization headquartered out of the East Bay. We spoke about the ADU regulatory challenges and opportunities for California, such as some current efforts to retool Title 24, California’s energy code to work better for small homes. Currently, detached ADUs are encumbered by Title 24 with the same standards and requirements as are used for large detached homes, including glazing requirements and appliances such as water heaters. But, these uniform energy efficiency standards generally cause special hardship for smaller homes, which is ironic because smaller homes are vastly superior to large homes from an energy conservation perspective.

Then I met with Hannah Bruegmann of Build it Green, a California non-profit organization that recognizes ADUs as a housing type with potential to address equity, affordability, and environmental wellness. She shared a wonderful video with me about the power efficiency calculator, which are techniques for living large and green on an existing electrical panel. This concept will grow in importance for those who wish to build ADUs and other energy intensive improvements such as adding EV charging outlets or dedicated RV outlets for mobile dwelling hookups, but who wish to do so without upgrading their electric service and panels, which commonly costs $4K-12K. 

The following day, I met with Karen Chappel, an ADU academic pioneer who researched them while teaching at the University of California Berkeley’s School of Environmental Design. 

Don’t hold Berkeley’s School of Environmental Design’s unfortunately designed building against them

One of the fascinating things that Chappel’s 2012 research uncovered was that 17% of residential housing stock in the East Bay are composed of informal ADUs (Understanding the Market for Secondary Units in the East Bay). Her research provided the academic foundation of much of the recent legislation in California. 

My first time meeting Karen Chappel, though I’ve been very familiar with her research for a decade

I then walked around a north Oakland neighborhood with Tom Limon, the director of the Casita Coaltion, and we sought out permitted ADUs using this public map. This fun exercise nonetheless confirmed to me that when it comes to finding ADUs ‘out in the field’, that the actual physical addresses and the permit ‘work description’ are more important to finding ADUs on the ground than solely providing a map with approximate locations. 

This is a technocratic tip directed to web and database technicians who work in municipal permit offices. ADUs are discreet by design and oftentimes internal conversions are difficult to identify from the street even when you know that you’re at the correct address, so it is often that only possible to easily ‘find’ them with permit work description (eg. “attached garage to ADU conversion”). 

There’s supposedly an ADU somewhere, but it’s impossible to figure that out from the street

This address and work description information should be public, query-able, and downloadable. While I’m at it, a lot of backend work generally needs to be done in the ‘municipal permit database’ space with an increased range of middle housing types, to both track and enable current middle housing.

The next day, I got a wonderful tour of four ADUs under construction with Carrie Shores Diller of Inspired ADUs, starting off with this one, which was just completed. 

This ADU cost $550K all in, give or take. Crazy, right? This is the new ‘normal’ cost for a nice ADU in the Bay Area market.

On the design side, here’s a neat pocket door design trick that I hadn’t seen before. 

Is it a living room?

Or, is it a bedroom?

Well, using these pocket doors, it’s both. Cool trick!

We toured another ADU under construction that is considering developing the ADU as an SB-9 standalone unit instead, based on the property layout. That is, the ADU could instead be developed and sold off separately as a standalone dwelling unit on a standalone property under California’s new Senate Bill 9 legislation

The following week, I was able to tour a Villa Home ADU. These are prefabricated ADUs that are competitively priced, and it is an example of a growing company offering a turn-key ADU solution. 

A list of Villa’s standardized models, Villa 450 through Villa 1200, the nomenclature refers to the square footage of the models.

This type of prefab is a rapidly emerging portion of the ADU market especially in ultra high cost labor markets like the Bay Area. A significant percentage of homeowner developers are desperate for these types of lower cost and off-the-shelf ADU solutions. 

Of note, the manufactured housing market is currently facing supply chain issues. The two lowest cost ADU prefab companies that I know of in the country (that each actually have more than 10 ADUs completed and in the ground) are now backed up 1.5 to 3 years due to high demand. 

Traditional site built ADUs have many issues such as high cost, but one benefit is that the process allows for on-the-fly flexibility. A traditional custom build process is more ‘nimble’ in terms working with significant supply chain material and labor slowdowns that the construction market is now experiencing for certain products like cabinets, windows, HVAC and plumbing fixtures.  

The ADU is on the right. The primary dwelling is on the left.

The prefabricated ADU is on the right side is actually larger than the primary dwelling, which is allowed in Santa Rosa, California, where this ADU is located. This is another visual example of where an SB 9 fee-simple lot partition might make more financial sense for the homeowner developer than keeping it as an ADU.  

Villa’s initial line of ADUs are built off-site as manufactured HUD code buildings rather than as built off-site as modular structures, which are built to local and state building codes.

That same day, I met with Renee Schomp of Napa Sonoma ADUs, and her colleague, Scott Johnson. This publicly funded NGO is comprehensively educating and assisting ADU homeowner developers in the Napa County and Sonoma County markets through a range of educational and consulting activities. We discussed financing opportunities, impacts of new CA legislation, permitting holdups, supply chain breakdowns, and more. 

These ADU meetings were interspersed with touring Berkeley in my free time, including an incredible array of stairs & pathways, doors, gates, and People’s Park. 

The Berkeley Hills have over 160 public staircases that serve as vertical shortcuts through steeply sloped residential neighborhoods

Berkeley hills’ architecture can be generally described as steep, custom, organic, and gorgeous

There’s also an inordinate number of stunning gates and arbors in Berkeley Hills, which gives fantastic architectural fabric for residents who walk the hill’s streets for pleasure and exercise.

People’s Park is soon to be developed as student housing. The many tent dwellers who live there will probably have to find another park to use as home base; I’m willing to wager that their next digs won’t happen to contain as much American history as People’s Park.

On the drive back to Portland, I stayed over in Talent, Oregon, a small town next to Ashland, Oregon, that was devastated by wildfires two years earlier. I stayed with a prolific ADU builder, Derek Sherrell, who gave me a tour of his affordable ADUs.

Talent’s ADU code allows for two ADU per property. The primary dwelling shown here is the rear unit, and the front two units are its detached ADUs.

Derek standing in the ‘storage loft’ space of his standard ADU

Derek builds a fairly standardized 520 sq ft ADU for approximately $60K, and is currently putting together a 200-step video series to open source to others about how to do the same. He does this sheerly as an advocacy matter to help spur others to develop ADUs. The West coast could use more Dereks.