Home Additions & ADU in Manhattan Beach - One Fixed Price, Permits Handled

Fast, Reliable Home Additions & ADU Across Manhattan Beach

A detached ADU in Manhattan Beach typically runs $90,000 to $220,000, while a garage conversion lands between $30,000 and $80,000, and a full home addition starts around $45,000 and can reach $130,000 depending on scope. Permitting here is the real wildcard: if your Sand Section lot sits in the coastal zone, you’re looking at city approval plus California Coastal Commission review, which adds months. We work with both agencies on almost every Home Additions & ADU project we take in the 90266 and 90267 ZIP codes. Call (877) 610-1318 and we’ll walk you through what applies to your specific street.

Call (877) 610-1318

Why Barrett & Sons Construction Is Manhattan Beach’s Preferred Home Additions & ADU Company

Tom Barrett founded this company in 1998, and he still shows up on Manhattan Beach job sites with his sons running the crews. That matters here more than most places, because Manhattan Beach construction has a rhythm all its own: crane permits through public alleys, formal neighbor notifications, stainless-steel hardware specs that inland contractors would never think to bid. When a homeowner on 33rd Street or Marine Avenue calls us, they get Tom’s cell number, not a regional call center. We publish our license number, our address, and our name on every estimate. You can look all three up before you sign.

We’ve built our Home Additions & ADU in Manhattan Beach reputation one permit inspection at a time. Every contract includes the 90-Day Done Right Promise in writing: if something’s not right, one call brings Tom back. Every price change arrives as a written change order before work starts. And the permit inspector works for you, not for us, which is exactly why we like having him on site. Homeowners between 50 and 70 have been burned before by national outfits that quote one number on the phone and hand over a different bill at the door. We don’t work that way, and the families we’ve built for in the Hill Section and the Sand Section will tell you the same.

Our Home Additions & ADU Services in Manhattan Beach

Most of what we do in Manhattan Beach falls into four buckets. Here’s how each one actually plays out on a 30-foot-wide lot with coastal permitting hanging over it.

ADU Design & Permitting

Manhattan Beach’s Sand Section enforces a 30-foot height limit, and because most lots are only 30 feet wide with zero side setbacks, a new detached ADU often must be integrated into the main home’s envelope or built over a garage. That makes Home Additions & ADU work here a dual-permit puzzle involving both city planners and, for coastal parcels, the California Coastal Commission. We handle both, and we bring a structural engineer and a draftsman to every initial walk, so you’re not paying for drawings before anyone’s confirmed the thing can actually be built.

Garage Conversion ADU

In the Sand Section, the original 1950s and 60s beach cottages often still have detached garages off the back alley. Converting one into a permitted ADU usually lands between $30,000 and $80,000 in Manhattan Beach. The catch: salt-laden sea air has been eating those garage frames for six decades, so expect to replace rotted framing and specify stainless-steel fasteners for every exterior connection, not zinc-plated hardware that’ll be rust-dusted in three years.

New Detached ADU

A new detached ADU in Manhattan Beach runs $90,000 to $220,000, and on a 30-foot-wide Sand Section lot, that almost always means building up, not out. Deep caisson or grade-beam foundations are the norm in the blocks closest to the beach because the sandy subsoil won’t support conventional spread footings without settlement. We design around that reality from day one, and we pull every permit before dirt moves.

Junior ADU & Interior Conversion

A JADU can be a smart move in Manhattan Beach, especially in the Hill Section where mid-century homes have larger footprints and interior square footage you can carve into a separate unit. The city’s rules on JADUs are more forgiving than on detached structures, but the builder warranty question still applies: if your home is newer, read the structural-warranty exclusions before anyone opens a wall. We’ll help you parse that before you commit.

Trusted Brands We Service in Manhattan Beach

We install materials you can look up, not mystery brands off a van. On Manhattan Beach additions and ADUs, we frequently specify Schluter for waterproofing and tile substrates in kitchens and baths, Grohe for fixtures that hold up to the coastal air, and GAF for roofing systems on the ADUs we build. We don’t stock local parts in some warehouse across town; we order per job with lead times built into the schedule, so you’re never waiting on a backordered vanity or a spec’d-before-approval window. If you have a brand preference, tell us. If you don’t, we’ll steer you toward the ones that survive salt air.

Common Home Additions & ADU Problems We See in Manhattan Beach Homes

• Salt-air corrosion on metal components. The persistent onshore marine layer accelerates rust on exterior hardware, rebar, and window frames far faster than even Redondo Beach or Torrance. We specify hot-dipped galvanized or stainless-steel fasteners and corrosion-resistant coatings as the baseline, not an upgrade.
• Foundation surprises in sandy subsoil. Blocks closest to the beach often can’t support conventional footings. We’ve seen homeowners pay for plans that assumed spread footings, then get hit with a $20,000 caisson change order after excavation. Our structural review happens before you sign anything.
• Builder warranties voided by unapproved structural changes. Many Sand Section new-build warranties exclude modifications to load-bearing walls without the builder’s written consent. An ADU addition that touches the main house can void that warranty if you don’t get the paperwork first. We check before we cut.
• HOA and architectural-committee stop-work orders. The Hill Section has mid-century homes in developments with HOA rules that can cap second-story rooflines or dictate exterior materials. A contractor who starts without checking can get a stop-work order in week one. We pull the architectural guidelines before we pull permits.

Pricing for Home Additions & ADU in Manhattan Beach, CA

We Also Serve Cities Near Manhattan Beach

Our crews regularly work Manhattan Beach, Redondo Beach, Rolling Hills Estates, Palos Verdes Estates, and Torrance. If your lot sits just outside the 90266 or 90267 ZIP, we’ll still come out for a free estimate and treat your project with the same coastal-construction care we bring to every Manhattan Beach job.

FAQs - Home Additions & ADU in Manhattan Beach