Free written scope consultation - allowances, timeline, and change-order rules on paper before a single trade is scheduled
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AfterFast, Reliable Home Additions & ADU Across Malibu
If you own a home in Malibu, you’ve likely hit the same wall: you need more space, but the lot is narrow, the coastal rules are thick, and you’re not sure a contractor from inland understands what a Coastal Development Permit even is. A home addition or ADU in Malibu typically runs $45,000 to $130,000 for additions and $90,000 to $220,000 for a detached ADU, and the permitting timeline can stretch months if you’re not working with someone who does this here regularly. We do. Call (877) 610-1318 for a free estimate from a team that knows the coastal zone paperwork, the fire-hardening rules, and the narrow-lot logistics better than most firms in the 90263, 90264, and 90265 ZIP codes.
Why Barrett & Sons Construction Is Malibu’s Preferred Home Additions & ADU Company
Barrett & Sons is owner-operated by Tom Barrett, founded in 1998, and run by his sons and their crews. When you call, you don’t get a call center. You get a live person, and when work starts on your Malibu property, Tom or one of his sons is on-site most days. That matters in a city where the Coastal Commission can issue a stop-work notice and you need someone who answers the phone, knows the inspector, and can produce a written change order before anything gets revised.
Malibu homeowners have been burned by outfits that quote one number on the phone and show up with another. We don’t do that. Every scope, every allowance, every price change arrives in writing before a single nail moves. Tom publishes his name, his address, and his license number. Look it up before you sign anything. The permit inspector works for you, not for me. That’s why I like him.
Our crews serve Malibu from our Los Angeles scheduling office, so we know Point Dume, Big Rock, the Colony, and the PCH corridor well enough to plan for lane closures and sand-loading windows that nobody from Valencia or Oxnard thinks about. If you’re in the Malibu area, you’ll see our trucks regularly, not just on a quote visit.
Our Home Additions & ADU Services in Malibu
We handle the full Home Additions & ADU build, but these four sub-services make up most of our Malibu work.
ADU Design & Permitting
Malibu sits inside the California Coastal Commission’s coastal zone, which means nearly every ADU project needs a Coastal Development Permit before the city will even look at your plans. We prepare those submittals, run the Chapter 7A ignition-resistant material specs, and coordinate with LA County fire for defensible-space compliance. A detached ADU here runs $90,000 to $220,000, and the design-permitting phase is where the schedule gets won or lost. We’ve done it on Point Dume, in the Colony, and up the canyon roads.
Garage Conversion ADU
Converting an existing garage is usually the fastest path to a rentable unit on a Malibu lot, since the footprint already exists and you dodge some of the caisson and foundation work that new detached ADUs require along PCH. Garage conversions in Malibu typically run $30,000 to $80,000. Salt air has usually eaten the bottom plates and anchor bolts on older garages, so expect some structural replacement before framing starts. We inspect and quote it honestly, in writing.
New Detached ADU
A new detached ADU on a Malibu lot means deep caissons on liquefiable beach sand if you’re near PCH, or hillside grading and retaining work if you’re up Kanan or Encinal. Chapter 7A exterior assemblies are not optional here: Class A roofing, ember-resistant vents, ignition-resistant siding. We spec Techo-Bloc and Cambridge pavers for exterior hardscape around ADUs where surfacing matters. Plan on $90,000 to $220,000, and plan on us pulling the permits, not handing you a “you do it” list.
Junior ADU & Interior Conversion
If you have an underused bonus room, attic space, or a large attached garage bay, a Junior ADU or interior conversion can add a studio or one-bedroom without touching the building footprint. That’s the cheapest square footage in Malibu. Most run $45,000 to $130,000 depending on whether you need a kitchenette, a separate entrance, and a new electrical subpanel. Marine-air corrosion near the coast means we replace any fastener and connector that’s been rusting for twenty years, using stainless or hot-dipped galvanized hardware as a practical standard, not an upgrade.
What happens when you call
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A real person answersNo phone trees - you reach a local pro.
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You get an upfront price rangeHonest numbers before anyone is dispatched.
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A background-checked tech heads outLicensed & insured, dispatched right away.
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You approve before work beginsNothing starts until you say go.
Trusted Brands We Service in Malibu
When we build in Malibu, we spec materials you can look up, not mystery brands off a van. For ADU and addition exteriors and hardscapes, we regularly install Techo-Bloc and Cambridge pavers, and we use Oldcastle products where retaining blocks and wall systems are needed. Stocking local parts and knowing which suppliers in the 90265 corridor actually keep ignition-resistant assemblies on hand means we’re not waiting three weeks for a vent that should have been ordered before demo. Kitchen Remodeling in Malibu and Bathroom Remodeling in Malibu are often folded into larger addition projects, and we handle those trades in-house with the same written-change-order rules.
Common Home Additions & ADU Problems We See in Malibu Homes
- Coastal Development Permit roadblocks. Many Malibu homeowners start with a city building permit only to learn later that the California Coastal Commission has jurisdiction over their lot. We map that early, so the ADU or addition doesn’t stall in month seven.
- Rusted hardware and salt-air corrosion. Pacific marine air eats standard steel anchor bolts, straps, and connectors faster than most inland contractors expect. We replace or spec galvanized and stainless hardware on any coastal build, which is one reason our Malibu bids look different from an Agoura Hills bid.
- Chapter 7A fire-hardening requirements. Nearly all of Malibu is in a Very High Fire Hazard Severity Zone. Post-Woolsey rebuilds and new ADUs must use Class A roofing, ember-resistant vents, and ignition-resistant exterior assemblies. An addition that doesn’t meet this can fail final inspection, and we know which products clear it.
- Narrow PCH lots and moving-lane staging. Beachfront parcels are often 30 to 40 feet wide with the highway at the back. Staging materials means coordinating moving-lane closures with Caltrans, and foundations on sandy, liquefiable soils need deep caissons rather than spread footings. That’s a Malibu-specific detail, not a generic one.
Pricing for Home Additions & ADU in Malibu, CA
In Malibu, a room addition typically runs $45,000 to $130,000. A detached ADU runs $90,000 to $220,000. A garage conversion runs $30,000 to $80,000. A Junior ADU or interior conversion usually lands between $45,000 and $130,000 depending on kitchenette and separate-entrance scope. The coastal-zone permit layer, caisson foundations near PCH, and Chapter 7A fire-hardening materials are the three big cost drivers that push Malibu above inland pricing. You will get a written line-item quote with no change orders unless they are signed in writing first. Call (877) 610-1318 for a free estimate. The allowance that isn’t on paper is a surprise waiting for a date.
We Also Serve Cities Near Malibu
Beyond Malibu proper, our crews regularly work in Agoura, Agoura Hills, Westlake Village, and Thousand Oaks. Same owner, same written change orders, same 90-Day Done Right Promise. If you’re just outside the coastal zone, the permitting path is often faster, and we’ll tell you that straight rather than pretending every job carries the same complexity.
Serving Malibu, CA - Our Local Coverage Area
We’re based in the Malibu 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 - Home Additions & ADU in Malibu
We usually schedule an estimate visit to Malibu within a few business days, and our crews are already working in the 90263, 90264, and 90265 ZIP codes during most of the year. A live person answers our phone 24/7, so you won’t get a voicemail box from an out-of-state call center. Call (877) 610-1318 to get on the schedule.
Yes. We work Point Dume, the Colony, Big Rock, the PCH corridor, and the canyon communities up into the Santa Monica Mountains. Beachfront lots with narrow frontage and Caltrans lane-closure staging are familiar work for us. We coordinate the Caltrans permits and the Coastal Commission paperwork, which is where most inland contractors stall.
Additions and ADUs are planned construction, not emergency work, so we don’t promise same-day starts on those. What we do promise is honest scheduling and a written start-date range. If a weather event or fire-weather shutdown interrupts an active Malibu project, we communicate immediately and document the delay in writing.
The coastal zone triggers a California Coastal Commission permit on most Malibu properties, adding design review time and submittal fees. Chapter 7A fire-hardening materials are mandatory across almost the entire city, and beach-adjacent lots often need deep caissons instead of standard footings. Those three factors push a Malibu ADU into the $90,000 to $220,000 range versus a lower inland baseline. We’ll show you the line items so the difference isn’t a mystery.
Every Home Additions & ADU job in Malibu carries our 90-Day Done Right Promise, written on the contract. If it’s not done right, Tom Barrett comes back and makes it right, one call. We also pull permits and pass inspections on every eligible job, so the city’s record shows the work was done to code, not just to a handshake. Call (877) 610-1318 for an exact quote, estimates are free.
Written by Tom Barrett, Owner at Barrett & Sons Construction, serving Malibu since 1998.