These are also known as Junior Accessory Dwelling Units (JADU) in the California ADU laws.

At the YIMBYtown conference in Boston, Massachusetts, last week, I heard from a panel comprising a developer, an architect, and a manager of special housing projects at the City of Boston. I forget who described this novel (sort of) multi-family housing configuration, but I noted it because it has benefits similar to Chicago’s coach & rear houses.

Here’s how it works.

There would be a residential building full of condos. Each condo would have a few bedrooms. One of the bedrooms would have its own kitchen or kitchenette, bathroom, and direct entry to the building’s corridor. The bedroom would be “locked off” from the rest of the condo. 

The condo owner would rent the bedroom to a tenant, providing them housing that would most likely be less costly than an equivalent (new construction) apartment.

As the condo owner’s household changes – perhaps the family has another child – the tenant can move out and the owner can remove the kitchen to create another bedroom or closet. 

Lock offs are heavily also present in time shares. 

The zoning question is whether this condo is treated as one unit or two.

If you’re trying to increase affordable housing in your municipality, it’s necessary to classify this condo configuration as a single unit. Anything more and it wouldn’t be possible to build any of these, as the building developer would run into minimum lot area per unit and FAR limitations. 

My friend Jacob Peters quickly drew a floor plan for what a lockoff condo would look like.  

According to the speaker, the project didn’t get off the ground because the developer couldn’t get lending because of lenders who don’t understand the model. Said the speaker, “We need spaces that can evolve as our lives change. And we don’t have that flexibility in our housing stock.”

Benefits of accessory dwelling units (ADUs) like coach & rear houses

  1. Increase the supply of affordable housing
  2. Increase income for homeowners
  3. Support aging in place – ADUs give families flexibility to share property and living spaces with extended family members
  4. Increase work for small and local architects and contractors
  5. Boost local business support by restoring a neighborhood’s historical density

Update: I’m happy to see that Lennar, one of the most prolific home builders in the United States, has included the lock-off apartment in their “Next Gen” house design. A sample floor plan is below. 

 

Sample floor plan of Lennar’s Next Gen suburban single-family house with lock-off apartment.