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 Manhattan Beach
Adding square footage in Manhattan Beach means working inside one of the tightest, most heavily regulated construction environments in Los Angeles County. A home addition in Manhattan Beach typically runs $45,000 to $130,000, while a full detached ADU runs $90,000 to $220,000, and every dollar of that hinges on getting the planning, the permits, and the logistics right the first time. Our crews know the Sand Section’s 30-foot lots, the coastal zone rules, and the inspectors you’ll meet along the way. If you’re weighing a room addition, a second story, or an ADU, call (877) 610-1318 and we’ll walk you through what’s realistic for your parcel.
Why Barrett & Sons Construction Is Manhattan Beach’s Preferred Home Additions & ADU Company
People in Manhattan Beach ask hard questions before they sign. They’ve watched neighbors endure nine-month Coastal Commission delays. They’ve heard stories about contractors who quoted a Hills Section addition and then stalled out on the foundation detail because the soil report came back sandy. We appreciate the skepticism, because we’ve spent 29 years earning trust the old way: scope in writing, allowances in writing, change orders in writing, and a permit inspector who works for you, not for us.
We’re the owner-operated alternative to outfits that treat Manhattan Beach like just another route on a dispatch board. Tom Barrett’s name, address, and license number are published and verifiable, look them up before you sign anything. The crew members who show up in Manhattan Beach carry the Barrett & Sons name, and they’re background-checked and uniformed on every visit. When a Manhattan Beach homeowner calls (877) 610-1318, a live person answers, 24 hours a day, 7 days a week. Not a voicemail box. Not an out-of-state call center.
We serve both sides of Highland Avenue: the Sand Section where the lots are 30 feet wide and the cranes come up the alley, and the Hill Section where mid-century homes get the additions and remodels they deserve instead of a tear-down. If you live in the 90266 or 90267 ZIP, we’re not a half-day drive away. Crews serve Manhattan Beach locally, with scheduling coordinated from our Los Angeles office. If something’s wrong, Tom wants to know about it, and he’ll be there to make it right. That’s the 90-Day Done Right Promise, written on every contract.
Our Home Additions & ADU Services in Manhattan Beach
Every Manhattan Beach addition starts with a realistic conversation about your lot, your setback lines, and what the city will actually approve. Here’s how we typically help:
ADU Design & Permitting
Manhattan Beach ADUs face a permitting path that surprises homeowners who’ve built elsewhere. If your parcel sits inside the coastal zone, the California Coastal Commission reviews the project alongside the city’s own planning department. That dual review can add months, and it demands drawings that anticipate objections before they’re raised. We handle the full design and permitting package, because the fastest way to stall a Manhattan Beach ADU is to submit plans that ignore the coastal overlay.
Garage Conversion ADU
A garage conversion in Manhattan Beach can be the most budget-friendly path to rental income or an in-law suite, but the Sand Section’s older 1950s and 1960s garages rarely meet current foundation or shear-wall standards. Sandy subsoil close to the beach often means the slab and footings need more attention than a typical inland conversion. A Manhattan Beach garage conversion generally runs $30,000 to $80,000 depending on how much of the original structure can be kept.
New Detached ADU
On Sand Section lots where the main house already pushes the 30-foot height limit, a detached ADU often has to work within a very small rear-yard footprint. That’s where careful design earns its keep. A new detached ADU in Manhattan Beach runs $90,000 to $220,000, and the single biggest variable is whether your lot’s soil conditions call for a conventional footing or a deeper caisson system. We’ll tell you which one applies to your parcel before you commit to a budget.
Junior ADU & Interior Conversion
For homeowners who don’t want to disturb the streetscape or lose yard space, a junior ADU carved from existing square footage can be the fastest permit path in Manhattan Beach. We look at underused bedrooms, oversized utility rooms, and attached garages, then design a conversion that meets the city’s size limit for a JADU. Interior conversions avoid most of the setback and height fights that slow down new structures.
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 Manhattan Beach
The salt air in Manhattan Beach punishes cheap materials faster than homeowners expect. That’s why we specify brands with proven corrosion resistance and long warranties, and we don’t substitute mystery materials off a van. For kitchens, we install KraftMaid cabinetry and Cambria countertops. On doors and windows, Andersen and Marvin. On the building envelope, GAF roofing products. When you ask for a written line-item quote, you’ll see exactly which of these brands is going into your Manhattan Beach addition, and every allowance gets confirmed on paper before you sign. No allowance on paper? That’s a surprise waiting for a date.
Common Home Additions & ADU Problems We See in Manhattan Beach Homes
We’ve worked on enough Manhattan Beach projects to know what goes wrong when additions and ADUs are handled by crews unfamiliar with the coast. Four issues come up constantly:
- Salt-laden air corroding fast hardware. The persistent onshore marine layer means standard galvanized fasteners, exterior brackets, and window frames fail years earlier in Manhattan Beach than they do five miles inland. We specify stainless steel or hot-dipped galvanized hardware as the baseline, not an upgrade.
- Sandy subsoil under shallow foundations. Blocks closest to the water in the 90266 ZIP often sit on sand that won’t carry a conventional footing. A proper addition here may need deep caissons or a grade-beam system, and we’ve seen too many owners discover that only after a cheap bid was already in motion.
- The dual-permitting gauntlet in the coastal zone. Parcels within the coastal zone need both Manhattan Beach planning approval and California Coastal Commission review. That’s not a single rubber stamp. It’s a sequence, it adds months, and it’s the single biggest reason Manhattan Beach additions run long. We plan for it from the first site visit, because we’ve sat through those reviews many times.
- Zero side setbacks and zero staging room. In the Sand Section, many homes are built wall-to-wall inside a 30-foot-wide lot. There is no place to park a crane except the public alley, and every delivery has to be choreographed to the hour. Inexperienced Manhattan Beach contractors lose days to bad logistics; we schedule each lift, each delivery, and each inspection window before work starts.
Pricing for Home Additions & ADU in Manhattan Beach, CA
You’ll see wide ranges online, and some of them are honest. A room addition in Manhattan Beach typically lands between $45,000 and $130,000. A detached ADU runs $90,000 to $220,000. A garage conversion runs $30,000 to $80,000. What moves the number most in Manhattan Beach is foundation work: sandy subsoil near the beach can require deep caissons that a standard inland quote never includes, and any parcel in the coastal zone adds design-review time that shows up in the final cost.
- Room Addition: $45,000-$130,000
- ADU Construction: $90,000-$220,000
- Garage Conversion: $30,000-$80,000
- Junior ADU / Interior Conversion: quoted per project after a site visit
We offer honest, no-hassle upfront pricing with written change orders before any scope change touches the job. We also offer a free second opinion on any written estimate, plus no trip charge inside the county. Call (877) 610-1318 to schedule your free estimate and get a line-item quote in writing.
We Also Serve Cities Near Manhattan Beach
Our crews work across the South Bay, so if you’re in Manhattan Beach today or looking in nearby Manhattan Beach communities, we’re close. That includes Redondo Beach, Rolling Hills Estates, Palos Verdes Estates, and Torrance. Wherever you are in the area, our Home Additions & ADU team brings the same written-pricing approach and local permitting knowledge to every job. If your addition grows into a full interior remodel, we also handle Kitchen Remodeling in Manhattan Beach and Bathroom Remodeling in Manhattan Beach as part of a single, coordinated scope.
Serving Manhattan Beach, CA - Our Local Coverage Area
We’re based in the Manhattan Beach 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 Manhattan Beach
A home addition in Manhattan Beach typically costs $45,000 to $130,000, with foundation requirements and coastal-zone review being the two biggest cost drivers. For an exact quote on your lot, call (877) 610-1318 and we’ll put the numbers in writing before you commit.
We serve every neighborhood in the 90266 and 90267 ZIP codes, including the Sand Section, the Hill Section, and the Tree Section. That means we know the permitting differences between a 30-foot-wide Sand Section lot and a Hill Section parcel with real side yards. Call (877) 610-1318 and tell us your cross streets.
We arrive quickly and on schedule, because a live person answers the phone 24/7 and crews serve Manhattan Beach locally. We’ll set a specific time and meet it. Call (877) 610-1318 to schedule your free estimate.
Manhattan Beach additions often run higher than inland neighbors like Torrance, because sandy subsoil near the beach can force deeper foundation systems and parcels inside the coastal zone face dual review from the city and the California Coastal Commission. A written line-item quote is the only honest way to compare. Call (877) 610-1318 for a free second opinion on any estimate you already have.
Yes. Every completed job is backed by the 90-Day Done Right Promise, written on the contract. If something’s not done right, Tom comes back and makes it right, one call. The permit inspector works for you, not for us, and Tom’s name, address, and license number are published and verifiable.
Get Your Home Addition & ADU Project Started in Manhattan Beach
If you’re ready to explore what’s possible on your Manhattan Beach lot, we’re ready to walk you through it honestly. We’ll review your parcel, your setback lines, your soil conditions, and your budget, then put a written line-item quote in your hands. No surprise invoices at the end, ever. Call (877) 610-1318 to schedule your free estimate.
Written by Tom Barrett, Owner at Barrett & Sons Construction, serving Manhattan Beach and the surrounding South Bay.