Fast, Reliable Home Addition Contractor Across Long Beach
A home addition in Long Beach typically runs $180 – $420 per square foot depending on whether you’re converting an existing garage, bumping out a wall, or building a second story. Most homeowners in Belmont Shore, Bixby Knolls, and the Wrigley district call us when they’ve outgrown their 1920s bungalow or 1950s tract home but love the block they live on. We’re the Home Addition Contractor team that handles both the city permit track and, where your lot falls inside the Coastal Commission boundary, the Coastal Development Permit track before a single form is set. Call (707) 383-5338 to talk through what your street will allow.

Why Seedling ADU Builders Is Long Beach’s Preferred Home Addition Contractor Company
Long Beach homeowners don’t just need someone who can frame a wall. They need someone who knows that a house on Naples Island faces a completely different permitting path than the same house on a lot in Lakewood Village. Ben Ortega leads our Long Beach work with the same approach every job gets: a written price before we start, background-checked uniformed technicians inside your home, and the Cedarwell Care Promise on every visit. That means shoe covers and drop cloths down before we walk through the door, pet-safe products wherever there’s a choice, and a photo of the clean-up before the crew leaves for the day.
We coordinate Long Beach scheduling from our Los Angeles office, but the crews working on your addition are local and know the difference between a California Heights historic review and a standard North Long Beach permit. Our 365-Day Done Right Promise covers every addition we build in Long Beach, in writing, so if something isn’t done right we make it right. That’s the whole promise.
Garage Addition Contractors in Long Beach
Garage Addition Contractors in Long Beach work with a housing stock that makes this the most common addition type in the city. Most homes here sit on 5,000 to 6,500 square foot lots with detached single-car garages of roughly 400 to 450 square feet. Those garages are often already past their useful life as storage, and converting or expanding one into living space adds square footage without giving up yard space. A garage addition or conversion in Long Beach runs $85,000 to $160,000 depending on foundation condition, electrical capacity, and whether the coastal permit track applies. If the slab has spalled from decades of salt air or the sub-panel hardware shows corrosion, those fixes get written into the price before work begins.
Slab Condition and Corrosion Reality
On a 1940s bungalow off East Ocean Boulevard in Belmont Shore, we found a detached garage slab that had begun to crumble from years of marine-layer exposure. The sub-panel mounting bolts were pitted enough that replacing them was the only safe option before energizing a new circuit. Long Beach’s salt air accelerates this everywhere west of Cherry Avenue, but it’s worst within a mile of the water. We specified James Hardie fiber-cement siding and stainless-steel fasteners on that job, and we’d do the same on yours if your lot sits in the coastal zone.
Permit Tracks That Change the Quote
On a garage addition in Belmont Shore, Naples Island, or the Peninsula, the city’s ADU approval is only step one. The Coastal Development Permit runs on a separate review clock and comes with design constraints like view corridor and drainage review. A quote that skips that permit is cheaper on paper and far more expensive in practice once the redesign fees land.
Bathroom Addition Contractor in Long Beach
A Bathroom Addition Contractor in Long Beach usually works on homes built before the era of the second bathroom. Those 1920s bungalows and post-war tract homes around Los Altos and Zaferia were built with one bath for the whole family, and the lines for adding a second one are an exercise in working around old cast iron and slab foundations. A bathroom addition in Long Beach typically runs $45,000 to $95,000 depending on whether you’re adding a powder room off a hallway or a full bath attached to a primary suite. The plumbing run distance, venting route, and whether the floor is slab-on-grade or raised foundation are the biggest cost drivers.
Working With Old Cast Iron and Slab Floors
Long Beach homes built before 1960 often have cast iron waste lines that have been in the ground for seventy years. Tapping into them for a new bathroom requires a careful inspection before we quote, because a corroded drain line found mid-project can add thousands you never agreed to. Our written price covers what we can see and what the inspection reveals before work starts, so the change-order conversation doesn’t happen after the floor is open.
Coastal Ventilation and Mold Resistance
Marine-layer humidity near the coast means a bathroom addition in Long Beach needs fans sized for real moisture loads, not just code minimums. We specify ventilation that moves enough air to keep a windowless bath from growing mold on the ceiling within two seasons, and the products we use hold up to the salt air better than standard builder-grade fixtures.
Trusted Brands We Service in Long Beach
We work directly with the brands serious ADU and addition buyers research before they call anyone. Abodu and Cover handle prefab ADUs that can sit on your Long Beach lot with minimal site disruption. Dvele builds factory-precision modules for homeowners who want a permanent second structure rather than a converted garage. Mighty Buildings offers panelized construction that speeds up the framing phase on tight Long Beach lots where staging space is limited. Because we’re set up with these brands, you’re choosing the right product for your lot, not just what a builder prefers to sell. Call (707) 383-5338 and we’ll walk you through which one fits your yard and your permit path.

Common Home Addition Contractor Problems We See in Long Beach Homes
- Coastal permit surprises. A homeowner in Belmont Shore gets a cheap quote that skips the Coastal Development Permit, then discovers mid-project that view corridor and drainage review adds months and redesign fees. We pull both permit tracks before we quote so this can’t happen.
- Soils reports on West Long Beach lots. The legacy of mid-century oil extraction left compaction and fill issues in the Wilmington-adjacent and West Long Beach corridors. A soils report frequently flags an engineered foundation requirement that a low bid never accounted for.
- Corroded sub-panel hardware. Salt air east of the Peninsula eats standard galvanized fasteners and untreated panel hardware within a few years. On coastal-zone additions we specify stainless-steel fasteners and corrosion-rated hardware, and we document it for your records.
- Historic district design review in California Heights. Additions within the California Heights Historic District face extra design-review requirements on exterior modifications. A compliant quote includes that review period; a cheap one pretends it doesn’t exist.
Pricing for Home Addition Contractor in Long Beach, CA
Here’s what we quote in Long Beach, in writing, before any tool is picked up. A garage conversion with a full ADU finish runs $85,000 to $160,000. A second-story addition runs $200,000 to $350,000 depending on structural work on the existing first floor. A bathroom addition runs $45,000 to $95,000. A single-room bump-out runs $60,000 to $120,000. The wild cards in Long Beach are the soils report on West Long Beach lots, the Coastal Development Permit near the water, and corrosion repairs on an older building. We show you every line item before work starts, and no surprise line items get added once crews arrive. Call (707) 383-5338 for a free estimate.
Key Takeaways
- Long Beach additions run $180 – $420 per square foot depending on the work type and permit track.
- Coastal-zone lots in Belmont Shore, Naples Island, and the Peninsula need both city and Coastal Commission permits.
- Written price comes first, always. No change orders added after the crew arrives.
- Every job carries the 365-Day Done Right Promise, in writing.
We Also Serve Cities Near Long Beach
Seedling ADU Builders handles home additions across the greater Long Beach area, including Signal Hill, Carson, Seal Beach, and Lakewood. If you’re a homeowner in any of these cities and want the same written-price, Care Promise approach, call us. We’re glad to help you understand the rule set on your side of the city line, because the coastal boundary doesn’t care about a ZIP code change. For broader coverage, see Home Addition Contractor in Long Beach or call (707) 383-5338.
Serving Long Beach, CA - Our Local Coverage Area
We’re based in the Long 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 About Home Addition Contractor in Long Beach
Yes. Any property inside the Coastal Commission’s coastal zone, which includes Belmont Shore, Naples Island, and the Peninsula, requires a Coastal Development Permit in addition to the city of Long Beach’s own ADU approval. The two permits run on separate timelines, and the Coastal Commission’s design constraints, including view corridor and drainage review, apply even if the city has already approved the project. Call (707) 383-5338 and we’ll confirm whether your property falls inside the boundary before we quote anything.
For additions within a mile of the water, we specify stainless-steel fasteners, corrosion-rated sub-panel hardware, and James Hardie fiber-cement siding where exterior walls face the prevailing marine-layer winds. Long Beach’s salt air accelerates corrosion on standard galvanized hardware, and using untreated panel components shortens the life of the electrical work. A compliant quote documents these ratings so your insurance company can see what was specified, not just what was installed. Call (707) 383-5338 for a written quote that includes the hardware specs line by line.
Documented compliance, meaning permits pulled, inspections passed, and materials specified for coastal conditions, gives you a clear record that any future failure was environmental or installation-related, not a code violation. If you ever file a claim on a failed sub-panel or corroded fastening system, that documentation shifts the conversation from “was this built wrong” to “what happened after it was built right.” We provide that documentation with every Long Beach addition, including the clean-up photos and the permit record. Call (707) 383-5338 to talk through what we’ll deliver on paper before we start.
Converting an existing detached garage is the most common ADU path in Long Beach because the city’s building stock has so many 400 to 450 square foot detached garages on 5,000 to 6,500 square foot lots. Whether a conversion or a new addition makes more sense depends on the slab condition, the garage’s structural framing, and whether the lot sits in the coastal zone, where a new detached structure may face additional review. We’ll inspect the slab and the framing, then give you a written price for both paths so you can compare. Call (707) 383-5338 to schedule the inspection.
Yes. Homes within the California Heights Historic District face additional design-review requirements that can restrict exterior modifications on additions, including rooflines, window patterns, and materials visible from the street. The review runs on its own timeline and is separate from the city’s building permit. We’ve worked within that district’s rules and we’ll tell you what’s workable before you commit to a design. Call (707) 383-5338 and we’ll walk the street with you, figuratively and literally.
When you’re ready to plan a home addition in Long Beach, call (707) 383-5338. We’ll answer, listen to what you’re trying to build, and give you a written price before any work begins. The estimate is free, and it’ll tell you more about your lot than most contractors will ever put on paper.
Written by Ben Ortega, Owner at Seedling ADU Builders, serving Long Beach with written pricing, the 365-Day Done Right Promise, and the Cedarwell Care Promise on every job.