Calabasas, CA
ADU Builders in Calabasas
Detached, attached and junior ADUs, permitted through the City of Calabasas and built for fire zones and HOA review.
★★★★★ 4.9 from 60 Google reviews
Most ADU advice online is written for the City of Los Angeles. Calabasas is its own city, with its own permit counter and its own ADU ordinance, so ADU builders in Calabasas have to work from a different rulebook.
That rulebook is also being rewritten to match state law. Here is what that means for your project.
Who Builds ADUs in Calabasas?
Master in Design builds ADUs in Calabasas from our Tarzana office, a short drive east on the Ventura Freeway. We design, permit and build detached units, attached units and junior ADUs through the City of Calabasas Building and Safety Division. Projects run $75,000 to $400,000, and construction takes 12 to 20 weeks once the permit issues.
At a glance
Calabasas Is Its Own Permit Office
Calabasas incorporated on April 5, 1991, which makes it the newest city in Los Angeles County. LADBS does not handle permits here. The City of Calabasas Building and Safety Division does, through its own Permit Center, Plan Check, Inspections and Code Enforcement sections at City Hall, 100 Civic Center Way.
The city takes plan submittals as electronic PDFs. A design drawn for a Los Angeles plan check often needs rework before it fits the Calabasas process, so we set the submittal up for Calabasas from the start.
That is the biggest difference from our Woodland Hills ADU builder work next door, where LADBS handles the permit.
Calabasas Is Rewriting Its ADU Rules
Calabasas has been replacing its 2020 ADU ordinance to match state law. Here is where that stands:
- The Planning Commission recommended a replacement ordinance, including a 1,200 square foot size cap, interior living space measurement and the removal of appearance controls
- On May 4, 2026, California’s Department of Housing and Community Development (HCD) sent written findings that the 2020 ordinance does not comply with state ADU law
- In June 2026, city staff reported the ordinance would be revised again to answer HCD’s follow-up letter
- On August 26, 2026, the City Council held a public hearing on an ordinance replacing the ADU section to align it with current California law
HCD’s findings targeted several 2020 rules: a one-story, 16 foot height cap on detached units, a 30 percent rear yard coverage limit, front setbacks, a requirement that an ADU’s design conform to the main house, a zoning clearance step and the lack of an appeals process.
Two limits hold either way. A detached ADU can reach 1,200 square feet, and a junior ADU up to 500 square feet. Where a local rule conflicts with state ADU law, state law controls. We check every design against the code in effect on the day we submit and against the state statute, so a plan check comment does not stall your project.
Fire Zones and the Woolsey Fire
Calabasas sits in the foothills of the Santa Monica Mountains, and much of the city falls inside a mapped fire hazard severity zone. The 2018 Woolsey Fire burned through the area and damaged Grape Arbor Park.
The city’s fire hazard page notes that homes in high or very high zones may be subject to Chapter 7A of the California Building Code and to defensible space rules. For an ADU, Chapter 7A means ignition-resistant construction:
- Class A roofing
- Ember-resistant vents
- Exterior walls and decks built to resist burning embers
- Tempered or multi-pane glazing
We check the current CAL FIRE map, last updated in March 2025, before design starts. It changes what goes on the materials list and the budget.
Calabasas, CA
Free estimate
Planning an ADU in Calabasas? Get a free estimate from our team.
What Calabasas Homeowners Say About Our Work
Rated 4.9 out of 5 across 60 Google reviews, with 42 more on Yelp.
★★★★★“Barak arrived well prepared with copies of the company’s license and permits and all required paperwork.”
Michal R.
verified Yelp review
★★★★★“The constant communication and progress updates from the crew were a huge difference, and every inspection passed on the first pass.”
Debby M.
verified Google review
★★★★★“Master In Design just completed my 600sq ft ADU (1 bedroom unit). I met with over 10 contractors before I chose to work with them.”
John A.
verified Yelp review
Who runs your project
Avi “Danny” Vaknin, owner
Avi Vaknin owns Master in Design, the Tarzana design-build firm serving the San Fernando Valley since 2012. Most clients know him as Danny.
Reviews describe him on site during the build and back at the house when something needs attention, sometimes years after the job is done.
HOAs and Calabasas Neighborhoods
Many Calabasas homes sit inside homeowners associations. California law voids HOA rules that effectively prohibit an ADU or unreasonably raise its cost, though reasonable design review still applies. We bring the HOA review into the schedule so it runs alongside city plan check, not after it.
What Does an ADU Cost in Calabasas?
Our ADU projects run $75,000 to $400,000. In Calabasas, three things push a project toward the top of that range:
- Chapter 7A materials on homes inside a fire hazard zone
- Hillside grading and engineered foundations on sloped lots
- HOA design standards that call for matching roof tile, stucco or windows
A junior ADU inside the main house avoids most of those costs. A detached unit on a flat lot with a short sewer run keeps the price lower too. Our main ADU construction page covers the types and process in more detail.
Areas We Serve in Calabasas
We build across Calabasas, ZIP code 91302. That includes Calabasas Hills, Calabasas Park Estates, The Oaks, Mont Calabasas and Calabasas Highlands. Older areas such as Mulwood and Park Moderne, the “Bird Streets,” sit toward Mulholland Highway. Projects reach us from homes near Old Town Calabasas and the Leonis Adobe.
For kitchens and baths, see our Calabasas remodeling page.
Frequently Asked Questions
What Calabasas homeowners ask before building an ADU.
Are prefab ADUs worth it?
What is the difference between an ADU and a modular home?
What's one drawback of an ADU?
Is it harder to sell a house with an ADU?
Do I need a permit to build an ADU in Calabasas?
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★★★★★
4.9 out of 5 from 60 Google reviews, plus 42 reviews on Yelp.
Licensed General Building contractor, CSLB #979219. Serving Tarzana and the San Fernando Valley.