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 Redondo Beach
A home addition or ADU in Redondo Beach runs $45,000 to $130,000 for a standard addition, and $90,000 to $220,000 for a detached ADU. Those numbers come with a local asterisk most contractors won’t mention: if your property sits in the coastal 90277 ZIP, the California Coastal Commission may need to sign off before the city even looks at your plans. Tom Barrett and his sons have worked through that process enough times to know exactly where the paperwork catches and how to keep the job moving. Call (877) 610-1318 and we’ll walk you through what applies to your street specifically.
Why Barrett & Sons Construction Is Redondo Beach’s Preferred Home Additions & ADU Company
Barrett & Sons Construction has been owner-operated since 1998, and Tom Barrett’s name is on the truck, the contract, and the license. That matters in a city like Redondo Beach, where a second-story addition near the Esplanade can run into Coastal Commission design review and a garage conversion in 90278 can trigger a soft-story seismic retrofit nobody warned you about. We publish our license number. You can look it up before you sign anything, and you should. It’s the same advice Tom gives neighbors at the hardware store.
A live person answers our phone 24/7, not a voicemail box and not an out-of-state call center. When you call about a home addition in Redondo Beach, you’re talking to someone who has walked the job sites on Avenue A and stood in front of the permit counter on Diamond Street. No franchise dispatching strangers. No price quoted on the phone that quietly changes at your front door. Every scope change arrives as a written change order before a single nail moves. That’s the Barrett & Sons way, and it’s why our Home Additions & ADU team gets called back by the same Redondo Beach families year after year.
Our reviews from Redondo Beach homeowners tell the story better than we can. Homeowners have pulled us aside at the Farmers Market on Tuesday nights and told us the same thing: they’d been burned by a national company that quoted one price and handed over a different bill. We don’t work that way. We draw up the scope in writing, price every allowance in writing, and stand behind the finished job with our 90-Day Done Right Promise. If it’s not done right, one call brings Tom back.
Our Home Additions & ADU Services in Redondo Beach
ADU Design & Permitting
This is the part where Redondo Beach splits from every inland South Bay city. An ADU in the 90277 ZIP can require California Coastal Commission review on top of city permits, especially anywhere west of Pacific Coast Highway or along the Esplanade. We handle the pre-application, the coastal development permit paperwork, and the city submittal as one coordinated package. You shouldn’t have to become a part-time permit consultant just to build a backyard unit.
Garage Conversion ADU
A detached garage conversion in Redondo Beach runs $30,000 to $80,000, but there’s a catch specific to 90278. Many garages there sit on 1960s and 1970s wood-frame properties that fall under LA County’s mandatory soft-story seismic retrofit ordinance. If inspection flags your building, the retrofit gets added to your project, and it’s not a small line item. We catch that during the estimate phase, not after framing is open. The allowance goes in the contract in writing before we start.
New Detached ADU
Marine-grade materials aren’t negotiable on a new detached ADU in Redondo Beach. The salt-laden wind off Santa Monica Bay will find standard galvanized fasteners and eat through them in under two years. We spec marine-grade stainless connectors, corrosion-resistant framing hardware, and coatings rated for constant salt-air exposure from the first drawing. It costs more up front and it means you won’t see rust bleeding through stucco before the paint is even dry.
Junior ADU & Interior Conversion
A junior ADU carved out of an existing bedroom or attached garage is the most budget-friendly way to add rental space in Redondo Beach, often landing between $45,000 and $90,000 depending on scope. What surprises most homeowners is what opening the walls reveals: outdated wiring, undersized framing, failed waterproofing behind original stucco. When we open a wall on a 1950s Redondo Beach home, we expect to find things that need fixing. We write those into the change order before touching anything else, and you approve it in writing first.
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 Redondo Beach
We install materials you can look up, not mystery brands off a van. For Redondo Beach ADUs and additions, that means Schluter waterproofing systems in any wet area, Sterling and Grohe fixtures where rental durability matters, and GAF roofing on any addition that ties into an existing roofline. Because the marine layer here accelerates corrosion on exposed metal, we stock marine-grade fasteners and connectors locally so a Redondo Beach job isn’t waiting on a parts run from across the county. If you’re replacing an old window inside an ADU, we’ll spec brands rated for coastal exposure. If you’re adding a sunroom near the Esplanade, we’ll tell you honestly which windows will hold up to the salt air and which ones won’t.
Common Home Additions & ADU Problems We See in Redondo Beach Homes
- Coastal Commission permit surprises. A contractor skips the Coastal Commission pre-application for an addition in 90277, and the project stalls at city permit stage after you’ve already paid for demolition. We file the pre-app before we ever ask you to sign a contract.
- Corroded galvanized framing connectors. On a 1950s stucco home near the Esplanade, our crew opened a wall for a second-story addition and found decades of salt-laden wind had eaten through the galvanized connectors. We replaced every one with marine-grade stainless, wrote the upgrade into the contract as a written change order before touching the wall, and the city inspector signed off the rough-in the same day the Coastal Commission permit cleared.
- Soft-story retrofit triggers in 90278. A garage conversion gets priced without a seismic retrofit allowance, and the inspection triggers a $18,000 upgrade after framing is already open. That’s why we look at the building’s retrofit status during the estimate walkthrough, not after.
- Water intrusion behind original stucco. The persistent marine layer in Redondo Beach pushes moisture into old stucco walls, and the wood framing behind them often fails quietly for years. When we open a wall, we expect to find it. The fix goes in the contract before we touch anything else.
Pricing for Home Additions & ADU in Redondo Beach, CA
A home addition in Redondo Beach runs $45,000 to $130,000, a detached ADU $90,000 to $220,000, and a garage conversion $30,000 to $80,000. Those ranges reflect the two things that drive cost here more than anywhere in the South Bay: Coastal Commission review in 90277, and marine-grade material mandates demanded by the salt air off Santa Monica Bay. Here is how the main line items break down:
| Project Type | Redondo Beach Price Range |
|---|---|
| Home Addition | $45,000 - $130,000 |
| ADU Construction | $90,000 - $220,000 |
| Garage Conversion | $30,000 - $80,000 |
We also publish our standing offers on every Redondo Beach estimate: $40 off any repair over $200, a free second opinion on any written estimate, no trip charge inside the county, and a permanent 10% Senior & Veteran discount. Call (877) 610-1318 for a free estimate. We’ll give you a written line-item quote, not a number someone pulls out of the air over the phone.
We Also Serve Cities Near Redondo Beach
Our crews work throughout the South Bay, including Hermosa Beach, Palos Verdes Estates, Manhattan Beach, and Marina del Rey. If you’re just north or south of the Redondo Beach city line, the rules may differ, and we’ll tell you straight up what applies to your address. You can learn more about our work across the South Bay on our Home Additions & ADU in Redondo Beach page, or call us and ask Tom directly.
Serving Redondo Beach, CA - Our Local Coverage Area
We’re based in the Redondo 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 Redondo Beach
No. Only properties within the coastal zone, which covers much of the 90277 ZIP west of Pacific Coast Highway and along the Esplanade, typically require California Coastal Commission review in addition to city permits. Homes in inland 90278 generally do not need Coastal Commission involvement unless they sit on a bluff or within a designated environmentally sensitive area. We check your parcel against current coastal zone maps before we quote anything, so you know on day one which process applies to you. Call (877) 610-1318 and we’ll check your address.
For any new ADU or addition in Redondo Beach’s salt-air corridor, we use marine-grade stainless steel framing connectors, corrosion-resistant structural hardware, and exterior coatings rated for sustained coastal exposure. The constant onshore wind off Santa Monica Bay deposits salt on everything, and standard galvanized fasteners can show visible rust through stucco within two years. The city’s inspectors know this, and they’re looking for it. We spec the marine-grade hardware as part of the base bid, not as an upgrade you find out about later.
What usually happens is this: the wall comes open, the framing behind the stucco is worse than the plans anticipated, and the contractor sends you a surprise bill with no paperwork. We handle it differently. We expect old Redondo Beach homes to hide outdated wiring, failed waterproofing, and corroded framing connectors. That’s why we build realistic allowances into the contract up front, and why any scope change arrives as a written change order before work proceeds. No surprise invoices at the end. Call (877) 610-1318 for a quote that accounts for what old stucco actually hides.
It depends on the building’s retrofit status under LA County’s mandatory soft-story ordinance. If the structure is flagged and hasn’t been retrofitted, an ADU conversion will likely trigger the requirement, adding roughly $18,000 or more to the project. We check the retrofit status during our free estimate walkthrough, so you know before you sign. If a retrofit is triggered, it goes into the contract as a written allowance, not as a surprise after framing is open.
Realistically, 12 to 18 months from first drawing to final inspection if the property falls within California Coastal Commission jurisdiction. The Coastal Commission’s design review alone can add 6 to 12 months and $15,000 or more in consulting fees on top of the city permit process. If your property is outside the coastal zone, a second-story addition can often be permitted and built in 6 to 9 months. We’ll give you a straight timeline for your specific address before you commit to anything, and Tom will tell you honestly if the Esplanade location means waiting longer.
Ready to talk about your Redondo Beach addition or ADU? Call Barrett & Sons Construction at (877) 610-1318. Tom or one of his sons will pick up. We’ll schedule a free estimate, look at your property in person, and give you a written quote that accounts for Redondo Beach’s coastal regulations, marine-grade material mandates, and the surprises hiding in old stucco. Permits pulled, inspections signed, change orders in writing, and the 90-Day Done Right Promise on every job.
Written by Tom Barrett, Owner at Barrett & Sons Construction, founded in 1998 and serving Redondo Beach and the South Bay.