Everyone loves an ADU loft! It’s like an indoor treehouse where you can curl up and read a book, take a nap, or get some work done.

But there’s a lot of confusion around lofts.

Some of our homeowners have seen lofts in tiny houses and assume you can add one to the interior of any structure. Just make the ceiling high enough to squeeze under, lean a ladder next to it, and you’re done. Right?

Not when you’re building a granny flat in California.

Lofts are second stories

The state of California considers an ADU loft to be a second story. Like any habitable bedroom or living room, the loft must have an area where the ceiling is at least 7 feet high. Parts of the loft can be lower, for example, the perimeter where a sloping roofline ends.

The regulations for tiny houses are different. They can have sleeping lofts with headspace much lower than what is required for second stories in permanent structures such as ADUs.

Staircases take up space–so make them do double duty

Just as you wouldn’t use a ladder to climb up to the second story of your house, you’ll need a permitted stairway to get to your loft. No ladders allowed.

Should you choose a spiral staircase or regular stairs?

Spiral stairs can fit into tight spaces, so that’s terrific for small ADUs. They’re beautiful and add character to a room. But spiral stairs are hard for some people to climb, which could make the ADU less attractive to renters.

And you can’t plunk a spiral staircase just anywhere. There is math involved: the stairs must begin where you can easily take the first step, and end where you can step onto the loft’s floor, not into mid-air. There are regulations regarding the depth of the stairs. Your designer needs to factor all this into the plans from the beginning.

A regular staircase is easier for people to climb than a spiral staircase. You can also use it as storage: open shelving built into the side of the stairs is an excellent use of space in an ADU. Or you can tuck a closet or desk under the stairway. Some creative builders have even made steps that double as drawers.

The main disadvantage of a staircase is that it takes up more square footage than most people realize—which is why using it for storage is such a good idea.

Want to brainstorm loft ideas for your ADU? Call Maxable and check your address and see what Maxable can do for your home during an ADU Planning Call.

Why are ADU lofts expensive?

Because they are second stories. You can’t just “add” a loft to a one-story ADU. All the cost that goes into building a two-story ADU goes into a loft. There are more materials: lumber, insulation, flooring, drywall, and so on. You need more extensive infrastructure for the second floor. And you need to build the stairs. The only difference is that there is no floor over the section of the loft that’s open to the downstairs living area.

ADU LoftPros and cons of building an ADU loft

Is a loft right for your ADU?


  • A loft adds loads of charm to your ADU. That makes it more appealing to both short-term and long-term renters.
  • If you’re using your granny flat as a short-term rental, the loft will give you valuable sleeping space for more guests.
  • With its soaring ceiling height, the living area in a lofted ADU feels much larger than its footprint.
  • The two-story wall in the living area lets you add extra windows or shelving. It’s perfect for mounting a big-screen TV.
  • Loft space is flexible: you can use it as a sleeping area, workspace, studio, or storage.


  • A loft will increase the cost of your ADU.
  • If you are planning to convert a garage to an ADU, and the garage is in a power utility easement (near power lines), the second story might make it harder to get an encroachment permit that allows you to build.
  • Depending on how the ADU is situated in relation to the main house, a loft could result in a loss of privacy for the people in both houses.

If your granny flat dreams include a loft, be sure to tell your designer. It’ll add to your construction budget, but there’s a big payoff in charm and potential income!

Plan, hire, and manage your ADU project with Maxable.

It all begins with an ADU Planning Phone Call. Talk to you soon!