Free written scope consultation - allowances, timeline, and change-order rules on paper before a single trade is scheduled
Fast, Reliable Home Additions & ADU Across Redondo Beach
Adding square footage to a Redondo Beach home is different from almost anywhere else in the South Bay, and the reason is simple: location changes everything. A detached ADU in the coastal 90277 ZIP can pass through two separate permitting agencies before a single footing gets poured, while a second-story addition on a sloping lot near the Palos Verdes foothills often needs a soils report most contractors never mention until the slab cracks. We’ve been building additions and ADUs in Redondo Beach long enough to know what the Coastal Commission will flag, what the salt air will eventually destroy, and what’s hiding inside a 1950s stucco wall. Call us at (877) 610-1318 and let Tom Barrett walk the property with you before you spend a dollar on plans.
Why Barrett & Sons Construction Is Redondo Beach’s Preferred Home Additions & ADU Company
Founded in 1998, we’re an owner-operated company where Tom Barrett’s sons run the crews. That’s not a talking point; it means the person who signs your contract is related to the people swinging hammers on your property. Redondo Beach homeowners deal with us directly, not a rotating door of subcontractors recruited from a parking lot at 6 a.m.
Residents from the Avenues to the inland 90278 neighborhoods consistently tell us the same thing: they’re done with contractors who quote one price on the phone and show up with a different number. Our practice is simple. Every scope, every allowance, every price change arrives as a written change order before work happens. Tom publishes his name, his address, and his license number so you can look him up. When a live person answers our phone 24/7, that’s someone who knows your street, not a call center in another state.
And because we carry premium brands like Schluter, GAF, and Grohe, your Redondo Beach ADU gets materials you can research, not mystery products from the back of a van. The 90-Day Done Right Promise is written on every contract: if it’s not done right, one call brings Tom back to make it right.
Our Home Additions & ADU Services in Redondo Beach
Every project starts with the same question: what’s really inside this house? We inspect first, write allowances into the contract, and price any surprise in writing before we touch it. Here’s how that plays out across the services homeowners request most often in Redondo Beach.
ADU Design & Permitting
In coastal Redondo Beach’s 90277 ZIP, an ADU above certain square footage triggers California Coastal Commission design review on top of city building permits. That’s a second, independent layer that can add months. We map the path from site survey to signed permit before you spend money on construction drawings, so there are no 12-month surprises hiding in the schedule.

Garage Conversion ADU
Converting a detached garage on an inland 90278 property is one of the fastest ways to add rentable square footage in Redondo Beach, typically running $30,000 to $80,000. But many 1960s-era garages here were built on slabs without rebar and framed with lumber that’s been soaking up marine air for fifty years. We check for soft-story conditions and electrical panel capacity first, then write allowances for what the open walls actually reveal.

New Detached ADU
A ground-up detached ADU in Redondo Beach runs $90,000 to $220,000 depending on size, site access, and the geotechnical story your lot tells. On sloping southern 90277 terrain near the Palos Verdes foothills, expect a soils report before final engineering. We use marine-grade hardware and stainless connectors as baseline practice here, not an upsell.

Junior ADU & Interior Conversion
Sometimes the smartest addition is already inside your footprint. Converting an attached space, an oversized laundry room, or a portion of a 1960s garden apartment building into a Junior ADU works well in the denser inland 90278 neighborhoods where setback requirements squeeze detached units. We’ll tell you honestly whether your existing electrical service can handle the added load or whether a panel upgrade should go on the change order before rough-in begins.

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 Redondo Beach
We stock and install materials that hold up in Redondo Beach’s marine environment, and we’ll tell you which ones fail prematurely when the salt air gets to them. Schluter waterproofing systems come standard in our bathroom and utility installations because they stop the moisture intrusion that coastal humidity amplifies. For roofing on any second-story addition or new ADU, GAF’s coastal-rated lines handle the onshore wind and salt exposure far better than budget shingles. And Grohe fixtures give you German engineering that doesn’t show corrosion staining after two winters within a half-mile of the Esplanade.
Common Home Additions & ADU Problems We See in Redondo Beach Homes
- Coastal Commission design review catches people off guard. A homeowner signs with an out-of-area contractor for a “simple” room addition, only to discover the 90277 property triggers state coastal review. The project stalls for twelve months. We check jurisdiction before plans are drawn.
- Salt air eats standard hardware. Reusing existing 1960s stucco exterior walls without marine-grade weep screeds or corrosion-resistant fasteners leads to rust staining and spalling within two winters. We spec stainless before the first cut.
- Sloping lots hide expansive clay. A southern 90277 lot near the Palos Verdes foothills looks flat from the street but shifts under a new slab. Skipping the soils report means cracks within a year. We order the geotech report when the lot history warrants it.
- Older framing can’t always carry a second story. The post-WWII stucco homes that dominate Redondo Beach were built to 1950s standards. Adding a second story may require a new steel beam, and that’s not a guess, it’s a calculation. We don’t skip the structural review.
Pricing for Home Additions & ADU in Redondo Beach, CA
Here’s what we’re seeing in Redondo Beach’s market as of this year:
| Project Type | Typical Range in Redondo Beach |
|---|---|
| ADU Construction | $90,000 - $220,000 |
| Garage Conversion ADU | $30,000 - $80,000 |
| Second Story Addition (Home Addition range) | $45,000 - $130,000 |
What moves the number on a Redondo Beach project? The Coastal Commission overlay on 90277 properties adds design review fees and schedule time. A soils report may add $2,000 to $4,000 when the lot slopes. Upgrading electrical service for a Junior ADU or garage conversion can run from $3,000 to $6,000 depending on panel condition. Marine-grade materials run 10% to 20% above standard hardware, and we won’t substitute cheaper options to make a bid look better. We don’t use allowances as a way to lowball a quote; we use them to price reality, and you’ll see every number before we touch a wall. Call (877) 610-1318 for a free written estimate.
We Also Serve Cities Near Redondo Beach
Our Redondo Beach crews regularly work the coastal streets of Hermosa Beach, the view lots of Palos Verdes Estates, the tree-lined blocks of Manhattan Beach, and the marina-side properties of Marina del Rey. Same inspection-first process, same Home Additions & ADU warranty, same live person on the phone.
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
A detached ADU in coastal Redondo Beach’s 90277 ZIP can take 12 to 18 months to entitle when Coastal Commission design review applies, versus roughly 4 to 6 months for a comparable inland project that only needs city permits. Plan on an extra $8,000 to $15,000 in consultant, design-review, and entitlement fees for a coastal-overlay ADU. We map the full permitting path before you commit to construction drawings, so the schedule and the cost are real numbers, not hopes. Call (877) 610-1318 for a written estimate that includes the coastal review you’ll actually face.
Expect cloth-insulated wiring, undersized framing, and moisture damage near windows, and plan for code upgrades the permit inspector will require once walls are open. We write allowances for electrical replacement, framing reinforcement, and waterproofing into the contract from day one. When we opened the walls of a 1954 stucco home in the Avenues above Torrance Beach, we found original knob-and-tube wiring, a garage slab with no rebar, and window hardware eaten through by salt air. The homeowner wanted a garage-conversion ADU; we wrote an allowance for the electrical replacement, flagged the load-bearing wall for a new steel beam, and had a change order signed before we touched the rough-in. That project passed Coastal Commission design review and city inspection the same week, with marine-grade flashing and stainless connectors throughout.
Most 1970s-era Redondo Beach garages were built with 60-amp or 100-amp panels that cannot support the added load of a Junior ADU’s kitchenette, heating, and lighting circuits. Upgrading to a 200-amp panel typically runs $3,000 to $6,000 in this market, and skipping it is a code violation the city inspector will catch. We price the upgrade as a written line item before work begins, not as a surprise at rough-in. Call (877) 610-1318 and we’ll tell you what your panel actually needs after a physical inspection.
The marine layer and salt-laden onshore wind off Santa Monica Bay travel much farther inland than the first few blocks, and corroded fasteners, rusted window frames, and spalling stucco are routine failure points on homes half a mile from the sand in 90278. Standard zinc-plated hardware rusts within two winters; marine-grade stainless and proper weep screeds are baseline practice here, not an upgrade we pitch. We build every Redondo Beach sunroom and enclosed patio addition with that reality priced in from the first estimate.
That’s false for most 1960s wood-frame garden apartment buildings in Redondo Beach’s 90278 ZIP, which fall under LA County’s mandatory soft-story seismic retrofit ordinance. Adding an ADU in the carport area changes the structural loading and triggers retrofit review. A contractor who says otherwise is either unfamiliar with local code or hoping you won’t notice. We pull permits and we get the structural engineer involved before you sign anything. Call (877) 610-1318 for a free second opinion on any written estimate you’ve received.
Written by Tom Barrett, Owner at Barrett & Sons Construction, serving Redondo Beach and the South Bay.







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