Fast, Reliable New Detached ADU Across Calabasas
A new detached ADU in Calabasas typically runs $320,000-$580,000 all-in, from permit-ready drawings through final inspection, with most projects taking 14-22 months including HOA architectural review. We’re Ellery ADU Studio, and our New Detached ADU team coordinates every permit submittal, HOA board presentation, and inspection from our Los Angeles office. Calabasas homeowners call (820) 444-6584 because we understand the dual-track approval reality here: city building permits plus HOA architectural review, not one or the other.
We’ve designed, permitted, and built ADUs in The Oaks of Calabasas, Calabasas Park, and along Mulholland Drive since 2015. The lots are generous, the design standards are strict, and the fire-hazard construction rules are non-negotiable. We know which roof profiles pass the architectural review boards and which Chapter 7A ignition-resistant assemblies satisfy Calabasas building inspectors. That local fluency keeps timelines intact and budgets predictable.
Why Ellery ADU Studio Simi Valley Is Calabasas’s Preferred New Detached ADU Company
Our reputation in Calabasas rests on one fact: we’ve never had a project derailed by an HOA board we didn’t anticipate. We identify the architectural review requirement in our first site visit, then build the submittal packet to match the community’s design guidelines before the city ever sees a plan. Calabasas homeowners receive a written price before any work starts, per Haven Standard Clause 1, and a documented photo record on every visit so they see what we found, not what we felt.
Response time matters when you’re carrying two mortgages or counting rental income. We schedule site evaluations in Calabasas within 3-5 business days, and our crews serve the city locally from our Los Angeles coordination office. The 365-Day Done Right Promise backs every project in writing: if the finished ADU doesn’t match the permitted drawings, we make it right.
We’ve completed 900+ ADUs since 2015, every one with a written price locked at signing and a photo-documented build record. A live person answers calls 24/7 at (820) 444-6584. We also offer a Free Second Opinion on any written estimate already in hand.
Our New Detached ADU Services in Calabasas
Custom Built ADU
Custom built ADUs are the right fit for most Calabasas properties because HOA architectural review boards demand visual continuity with the primary residence. In The Oaks of Calabasas and Calabasas Park, we’ve built custom detached units that mirror the Spanish Mediterranean tile roofs, stucco textures, and eave depths of the main house. Our design-build team produces the permit set, manages the HOA submittal, and constructs the unit under one contract at one written price. Typical range in Calabasas: $380,000-$580,000 for a 1-bedroom or 2-bedroom detached unit, including dual-track approval support and Chapter 7A fire-resistant construction.
Prefab ADU Installation
Prefab ADU installation in Calabasas requires careful brand selection. We specify and coordinate systems from Cover, Dvele, and Mighty Buildings, but only after confirming the HOA architectural review board will accept the proposed roofline, cladding, and color palette. Most Calabasas HOAs reject flat roofs and modernist profiles that clash with Tuscan Revival or Spanish Mediterranean streetscapes. When a prefab solution works, we coordinate delivery, crane placement, and utility tie-in through the same single contract. When it doesn’t, we tell you before you’ve spent a dollar on drawings.
Modular ADU
Modular ADU construction in Calabasas faces the same design-scrutiny barrier as prefab. Boxabl and other modular systems can work on unincorporated LA County parcels nearby, but Calabasas gated communities generally require site-built or heavily customized solutions. We evaluate your specific HOA’s design guidelines before recommending any modular path. If the board approves, we manage factory coordination, transport, and set-and-finish construction. If not, we pivot to custom stick-built without restarting the design process.
Studio ADU
Studio ADUs, typically 400-600 square feet, are popular in Calabasas for home offices, guest quarters, and rental income on properties where the primary residence already commands significant value. In Calabasas Park, we built a 600-square-foot detached studio ADU for a 1990s Spanish Mediterranean tract home whose HOA required the new unit’s tile roof, stucco color, and eave depth to visually match the primary house. We submitted a full exterior finish schedule and roof-plan overlay to the architectural review board before pulling the building permit, then sequenced framing and stucco to wait only on the board’s sign-off, not on the city. Because the parcel also sits in the Very High Fire Hazard Severity Zone, we built the walls and roof assembly to Chapter 7A with Class A roofing and ember-resistant vents so the same inspection could clear both HOA and fire-hazard requirements. Studio ADUs in Calabasas typically run $320,000-$420,000 all-in.
1-Bed & 2-Bed ADU
One-bedroom and two-bedroom detached ADUs maximize rental income and multigenerational living on Calabasas’s quarter-acre-plus lots. These units require full kitchen and bath permits, separate utility metering where desired, and careful setback compliance with both city code and HOA open-space requirements. We design for the specific lot coverage and floor-area-ratio limits of your community, then build to the approved drawings with no scope creep. Typical range: $420,000-$580,000 depending on bedroom count, finish level, and site conditions.
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.
Trusted Brands We Service in Calabasas
We specify and coordinate prefab and modular systems from Cover, Dvele, Mighty Buildings, Boxabl, Plant Prefab, Tuff Shed, and James Hardie, but in Calabasas we lead with custom design-build work because HOA architectural review boards rarely approve off-the-shelf aesthetics. When a brand’s system can be customized to match Spanish Mediterranean or Tuscan Revival profiles, we coordinate factory production, delivery, and finish carpentry through our single contract. Our Los Angeles office maintains relationships with regional distributors so material lead times don’t extend an already complex dual-track approval calendar.
Common New Detached ADU Problems We See in Calabasas Homes
- Prefab or modular units designed without HOA pre-approval. We regularly see Calabasas homeowners purchase a flat-roof prefab unit from an out-of-area vendor, only to have their architectural review board reject it for clashing with the community’s tile-roofed streetscape. We verify HOA design compatibility before any deposit changes hands.
- City plan check and HOA review treated as one queue. Some projects break ground after city permit issuance, then sit half-framed for months waiting on an HOA design committee that hasn’t even seen the finish schedule. We sequence approvals so construction starts only after both the city and the board have signed off.
- Septic system surprises on Las Virgenes Road corridor lots. Hillside and canyon-adjacent parcels in upper Calabasas neighborhoods are frequently on private septic systems rather than municipal sewer. Adding an ADU triggers a percolation evaluation and often a full septic expansion or costly conversion to Las Virgenes Municipal Water District sewer connection. We test this in our initial site evaluation, not mid-build.
- Chapter 7A fire-hazard construction underestimated in budgeting. Most of Calabasas falls within California’s Very High Fire Hazard Severity Zone. Class A roofing, ember-resistant vents, and fire-resistant exterior cladding add meaningful cost and require inspectors familiar with VHFHSZ compliance. We build these requirements into the initial written price, not as a surprise change order.
Pricing for New Detached ADU in Calabasas, CA
New detached ADU pricing in Calabasas reflects three local realities: dual-track approval support, Chapter 7A ignition-resistant construction, and often custom site-built design to satisfy HOA boards. Here’s what we typically see:
| ADU Type | Typical All-In Range (Calabasas) |
|---|---|
| Studio ADU (400-600 sq ft) | $320,000-$420,000 |
| 1-Bedroom Custom ADU (500-750 sq ft) | $380,000-$480,000 |
| 2-Bedroom Custom ADU (700-1,000 sq ft) | $480,000-$580,000 |
| Prefab/Modular (where HOA-approved) | $340,000-$460,000 |
These ranges include permit-ready drawings, city plan check, HOA architectural review support, construction, and final inspection. What moves a project to the high end: hillside grading, septic expansion or sewer connection, premium finishes matching a luxury primary residence, and complex HOA design iterations. Under Haven Standard Clause 1, every project receives a written price before any work starts. No call-for-pricing, no ballpark that balloons. Call (820) 444-6584 for your exact quote - estimates are free.
We Also Serve Cities Near Calabasas
Our crews work throughout the west San Fernando Valley and Conejo Valley corridor. We also build New Detached ADU in Calabasas for clients in West Hills, Canoga Park, Agoura Hills, and Winnetka. Each city has its own permit timeline and design context; we adjust the submittal packet accordingly.
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 - New Detached ADU in Calabasas
Yes, under California state law (AB 2221/SB 897), your HOA cannot ban an ADU outright. However, Calabasas HOAs retain full authority over architectural review, meaning they can dictate the unit’s roof style, materials, color, height, and placement to maintain community aesthetics. We navigate both the legal right to build and the design standards that determine what you can actually build. Call (820) 444-6584 to review your specific HOA’s guidelines.
HOA architectural review typically adds 2-4 months to a Calabasas ADU project, sometimes longer for communities with quarterly board meetings or extensive revision cycles. We submit a complete exterior finish schedule, roof plan overlay, and landscape integration plan with the initial application to minimize back-and-forth. Our team coordinates directly with your property manager and board liaison. Call (820) 444-6584 and we’ll outline the specific timeline for your community.
Sometimes, but only if the specific unit can be modified to pass your HOA’s architectural review board. Most Calabasas gated communities require rooflines, stucco colors, and exterior details that match the Spanish Mediterranean or Tuscan Revival primary homes. Flat-roof modern prefab units are generally rejected. We evaluate your HOA’s design guidelines before recommending any prefab or modular path from Cover, Dvele, Mighty Buildings, or Boxabl. Call (820) 444-6584 for a Free Second Opinion on any prefab proposal already in hand.
It means your new detached ADU must meet Chapter 7A of the California Building Code: Class A fire-rated roofing, ember-resistant attic and foundation vents, fire-resistant exterior cladding, and often enhanced defensible-space landscaping. These requirements add $15,000-$35,000 to typical construction costs and require inspectors experienced with VHFHSZ compliance. We build these specifications into every Calabasas permit set and written price. Call (820) 444-6584 for an exact quote.
Yes, if your parcel is on a private septic system rather than Las Virgenes Municipal Water District sewer, which is common in hillside and canyon-adjacent neighborhoods along the Las Virgenes Road corridor. Adding an ADU triggers a percolation test, and failed percolation often requires septic expansion or a costly sewer connection. We identify your utility status in our initial site evaluation and price the appropriate solution before design begins. Call (820) 444-6584 to schedule your evaluation.
Ready to build a new detached ADU that passes both city inspection and your HOA architectural review board? Call Ellery ADU Studio at (820) 444-6584 to schedule your free estimate. We’ll review your property, your HOA design guidelines, and your site conditions, then deliver a written price before any work starts - guaranteed under Haven Standard Clause 1.
Written by Nadia Ellery, Owner at Ellery ADU Studio, serving Calabasas since 2015.