Calabasas, CA
Room & Home Additions in Calabasas
Primary suites, bedrooms and second stories, planned for Calabasas plan check, fire zone materials and HOA review.
★★★★★ 4.9 from 60 Google reviews
A room addition in Calabasas runs through three reviews most valley homeowners never deal with at once: the city’s own plan check, fire zone construction rules and, often, an HOA.
Plan for all three from day one and the project moves. Here is how we approach additions in Calabasas, what they cost and how long they take.
Who Builds Room Additions in Calabasas?
Master in Design builds room additions in Calabasas from our Tarzana office, a short drive east on the Ventura Freeway. We design, permit and build primary suites, bedrooms, family rooms and second stories through the City of Calabasas permit process. Projects run $40,000 to $150,000 or more, and single-story additions take about 8 to 14 weeks of construction.
At a glance
Calabasas Permits Run Through City Hall
Calabasas has been its own city since April 5, 1991, the newest in Los Angeles County. LADBS does not issue permits here. The City of Calabasas Building and Safety Division does, with its own Permit Center, Plan Check, Inspections and Code Enforcement sections at 100 Civic Center Way.
The city takes plan submittals as electronic PDFs on 24 by 36 inch sheets. We prepare the set for the Calabasas process from the start, so the plans are not redrawn halfway through.
Fire Zone Rules for New Rooms
Calabasas sits in the foothills of the Santa Monica Mountains. The 2018 Woolsey Fire reached the area and damaged Grape Arbor Park, and much of the city falls inside a mapped fire hazard severity zone.
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. For an addition, that usually means:
| Part of the addition | What Chapter 7A changes |
|---|---|
| Roof | Class A roofing |
| Vents | Ember-resistant vents |
| Exterior walls | Ignition-resistant materials |
| Windows | Tempered or multi-pane glazing |
| Decks and eaves | Materials and details that resist burning embers |
We check the current CAL FIRE map, last updated in March 2025, before design starts. Those materials change the budget, so they belong in the first estimate, not a change order.
HOA Review Runs Alongside Plan Check
Many Calabasas homes sit inside homeowners associations. An association can require matching roof tile, stucco color, window style or rooflines, and its approval process has its own calendar.
We put the HOA submittal on the same schedule as city plan check. That way, an architectural review comment does not show up after the city has already approved the plans.
Calabasas, CA
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Planning an addition in Calabasas? Get a free estimate from our team.
What Homeowners Say About Our Additions
Rated 4.9 out of 5 across 60 Google reviews, with 42 more on Yelp.
★★★★★“This is our second project with Master and Design. We were thrilled with the kitchen and bathroom remodel they did for us 2 years ago, and I can say they outdid themselves with our master bedroom.”
Zai 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
★★★★★“Barak arrived well prepared with copies of the company’s license and permits and all required paperwork.”
Michal R.
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.
Ground Floor or Second Story?
| Option | When it fits | Watch for |
|---|---|---|
| Ground-floor addition | Lots with flat yard space next to the house | Hillside setbacks and grading on sloped lots |
| Second-story addition | Tight lots or homes with views to gain | Structural upgrades, stairs, and HOA height or view rules |
| Bump-out | A bigger kitchen, closet or bath without a full room | Roof tie-in to the existing house |
On sloped Calabasas lots, a second story can avoid expensive grading and retaining walls. On flat lots, building out is usually the better value.
If you need a separate unit with its own kitchen instead, see our Calabasas ADU builders page.
What Does a Room Addition Cost in Calabasas?
Our room additions run $40,000 to $150,000 or more. A bedroom bump-out sits near the low end and a second story near the top.
A 2026 Los Angeles cost guide puts ground-level additions at about $200 to $400 per square foot and second stories at about $400 to $600. For a full primary suite, the 2025 Cost vs Value Report puts a midrange project in Los Angeles at about $182,500. In Calabasas, three things often push a project higher:
- Chapter 7A materials on homes inside a fire hazard zone
- Grading and engineered foundations on hillside lots
- HOA standards that call for matching tile, stucco or windows
We give a written line-item estimate after design, so the price is set before construction. Avi “Danny” Vaknin, who owns Master in Design, keeps the permit file and the HOA submittal in-house.
Our main room addition page covers design, structure and finishes.
Areas We Serve in Calabasas
We build across Calabasas, ZIP code 91302. That includes Calabasas Hills, Calabasas Park Estates, The Oaks and Calabasas Highlands. Older areas such as Mulwood and Park Moderne 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 adding on.
What is the average cost of a 12x12 room addition?
What is the most expensive part of an addition to a house?
What is the cheapest way to add an addition to a house?
Can I build a room addition myself?
Do I need a permit for a room addition 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.