







A free site visit, a check of what your lot allows and a written, line-item price.
Get your free estimateADU Company in Calabasas, CA
Calabasas is not a typical suburban build site. The city sits inside the Santa Monica Mountains, which means nearly every ADU project here touches slope, setback, fire-zone, or oak-tree regulations before the first foundation is even discussed. We plan Calabasas ADUs around those constraints from day one, not after the survey comes back. Our written price covers the full scope of work, presented before any labor begins, so you can compare it against other bids on the same set of drawings. Call (805) 309-3020 to talk through your lot.
Why Calabasas Homes Are Different

Most Calabasas homes are large, upscale single-family properties, many in gated communities or on hillside lots with Mediterranean or Spanish styling. That housing stock changes the ADU conversation. A detached ADU behind a home in The Oaks reads differently than one behind a ranch house in a flatter city. We account for grading, retaining-wall work, view corridors, and how the new structure sits against an existing stucco or tile-roofed main house.
Then there is fire. Calabasas sits in a high-fire-hazard zone, and the city enforces fire-resistant building materials and defensible space requirements. That means hardened siding, ember-resistant vents, and sometimes tempered glass on the exposure side. We have worked with conventional builds using James Hardie siding and prefab platforms like Abodu and Cover, which lets us match materials to the fire code and the HOA design review at the same time. Hot, dry summers also push HVAC sizing: a poorly sized mini-split in Calabasas will fail during a Santa Ana heat event, and the occupant will notice within the first summer.
Our Main Calabasas Services
Homeowners in Calabasas call us most often for one of three jobs, each with its own dedicated page for pricing and scope.
Room Addition Contractor in Calabasas
A room addition in Calabasas usually means expanding a bedroom wing, adding a home office, or building out a ground-level bonus space. On hillside lots, the addition may require a setback variance, which is the city’s written permission to build closer to the property line than the standard rule allows. We handle that paperwork and match rooflines and stucco to the existing home so the addition does not look bolted on. Written pricing before the work begins is the rule here, not a favor. Room Addition Contractor in Calabasas

Garage Conversion Contractor in Calabasas
Many Calabasas homes already have oversized attached garages that sit empty. Converting one into a one-bedroom or studio unit is often the fastest and least expensive way to add rentable or in-law space without expanding the home’s footprint. The local wrinkle is HOA control: several Calabasas neighborhoods have CC&Rs that restrict or require design review for garage conversions, and some have native oak trees that limit where a new exterior door or window can go. We check those constraints before pricing the job. Garage Conversion Contractor in Calabasas

ADU Builders in Calabasas
A detached ADU in Calabasas requires careful site planning. Slope analysis, view preservation rules, and scenic corridor regulations all come into play, and the city’s hillside review can add design iterations before a permit is issued. We build both conventional stick-built ADUs and prefab units from partners like Abodu, Cover, and Dvele, choosing the method that fits the lot and the budget. The Garrison Standard applies either way: written price first, permitted work, one-year written guarantee. ADU Builders in Calabasas

What happens when you call
- 1
A real person answersNo phone trees - you reach a local pro.
- 2
You get an upfront price rangeHonest numbers before anyone is dispatched.
- 3
A background-checked tech heads outLicensed & insured, dispatched right away.
- 4
You approve before work beginsNothing starts until you say go.
Brands We Service in Calabasas
We work with James Hardie siding on conventional builds and with Abodu and Cover on prefab ADU projects. Because Calabasas fire code often dictates the exterior materials, we keep the selected product specs on file and coordinate factory delivery or supply orders to the lot. See our brands for the full list and the build method each one suits best.
Pricing for ADU Company in Calabasas, CA
| Service | Typical range in Calabasas |
|---|---|
| Prefab ADU (turnkey, incl. delivery and hookup) | $180,000 – $340,000 |
| Conventional detached ADU (600 – 1,000 sq ft) | $250,000 – $480,000 |
| Attached ADU / junior ADU conversion | $140,000 – $260,000 |
| Garage conversion to studio or one-bedroom | $110,000 – $190,000 |
| Primary suite addition | $160,000 – $300,000 |
| Second-story room addition | $240,000 – $420,000 |
| Single room extension (office, den, gym) | $90,000 – $180,000 |
| Site prep and foundation only | $35,000 – $80,000 |
Hillside grading, retaining walls, fire-code upgrades, and HOA design review are the biggest price movers in Calabasas. We put the price in writing before the work starts, so the number you approve on day one is the number on the final invoice.
Neighborhoods We Serve in Calabasas
We work throughout Calabasas from the gated communities along Parkway Calabasas to the hillside streets above Mulholland Highway. Typical scheduling for a site visit runs within a few business days, depending on how fast the HOA or city responds to a records request for your specific lot.
- The Oaks
- Calabasas Hills
- Mont Calabasas
- Calabasas Highlands
- Mountain View Estates
Service Area – Cities Near Calabasas
While this page covers Calabasas specifically, we also serve homeowners in nearby communities with similar terrain and permit realities. Our crews work in West Hills, CA, Topanga, CA, Canoga Park, CA, and Agoura Hills, CA. Dispatch and scheduling are coordinated from the brand’s Los Angeles office, with crews serving Calabasas locally.
Serving Calabasas, CA - Our Local Coverage Area
We’re based in the Calabasas area and know this community well. Use the map below to see our service coverage - if you’re nearby, we can almost certainly help.
FAQs About ADU Company in Calabasas

Yes. We plan every Calabasas ADU and addition around the city’s hillside, scenic corridor, and fire-zone rules. That includes slope analysis, fire-resistant materials, defensible space, and any oak tree or view preservation conditions. Call (805) 309-3020 if you want us to review your lot before you commit to a design.
It depends on the development. Several Calabasas neighborhoods have CC&Rs that restrict or require design review for ADUs and garage conversions. We check the governing documents for your specific tract before pricing the job, so you are not surprised later.
We usually schedule a site visit within a few business days. The city’s permit intake and any HOA design-review step then control the timeline. We keep the written price and the permit path moving in parallel, so neither stalls the other. Call (805) 309-3020 for a free estimate.
For an exact, written quote on an ADU, garage conversion, or room addition in Calabasas, call (805) 309-3020. We will walk the lot, check the fire and slope rules, and put the full price in writing before you make any commitment.
What happens when you call
- 1A real person answersNo phone trees - talk to a local adu pro.
- 2You get an upfront price rangeHonest numbers before anyone is dispatched. No surprises.
- 3We come out and measureLicensed & insured, at a time that suits you - the visit and the quote are both free.
- 4You get the price in writingLine-itemed, yours to keep, and nothing starts until you say go.
What Calabasas Customers Say
"Foundation and slab poured on schedule. Crew kept the yard orderly."
- Marian J."Honest feedback on what the lot could fit. Told me up front what would fit on the lot and what the setbacks would allow."
- Rita C."Insulation, drywall, and finishes were all well done. Feels like part of the house."
- Pete O.





