







A free site visit, a check of what your lot allows and a written, line-item price.
Get your free estimateADU Company in Seal Beach, CA
Fielding ADU Builders handles room additions, garage conversions, and backyard ADUs in Seal Beach, CA. The coastal location changes how we build: salt air corrodes fasteners faster than inland jobs, many lots sit on former wetlands with soft soil, and older beach cottages rarely match modern setback rules. If you’re researching an ADU company in Seal Beach, start with a written price and a permit plan, not a ballpark and a handshake. Call (361) 315-4177 for a free estimate.
Why Seal Beach Homes Are Different

Seal Beach housing breaks into three rough groups. Old Town, north of Main Street, holds 1920s and 1930s beach bungalows on narrow lots that often sit inches from the property line. The Hill, southeast of town, has larger mid-century homes with sloped driveways and retaining walls that complicate foundation work. College Park East and West, the inland neighborhoods, feature 1960s tracts with attached garages and standard setbacks.
Two things shape nearly every Seal Beach job. First, the marine layer. Constant moisture means we spec stainless or coated fasteners, moisture barriers under siding, and paint systems rated for salt exposure. Second, the city’s coastal zone rules. Any ADU within the coastal overlay triggers additional review, and some Old Town lots need a setback variance (the city’s written permission to build closer to the property line than the standard rule allows). We pull permits on every job and do not start until the city signs off.
If your lot is in a flood zone, which covers portions of Old Town and the low streets near the San Gabriel River, foundation elevation becomes part of the design conversation before we ever talk framing.
Our Main Seal Beach Services
Most Seal Beach homeowners call us about one of three projects: adding a room to the existing house, converting a garage into living space, or building a detached ADU in the backyard. Each service has its own Seal Beach page with local pricing and specifics.
Room Addition Contractor in Seal Beach
Room additions in Seal Beach usually mean expanding outward on a flat lot or building up on a sloped Hillside parcel. Old Town additions frequently trigger the coastal overlay, and College Park additions often run into utility easements along the side yard. We handle the full job: plans, permits, foundation, framing, electrical, plumbing, and finish work. Crews are background-checked and uniformed, and the written price you approve before work starts is the price on the final invoice. Room Addition Contractor in Seal Beach

Garage Conversion Contractor in Seal Beach
Garage conversions in Seal Beach are the fastest way to add a rental unit or in-law suite without changing the home’s footprint. Seal Beach garages often lack proper slab insulation and sit below the flood elevation, which means we address drainage and vapor barriers before drywall goes up. If the existing slab is cracked or out of level, we correct it rather than building over a problem. The city requires off-street parking replacement for most conversions, and we handle that paperwork with the permit set. Garage Conversion Contractor in Seal Beach

ADU Builders in Seal Beach
Detached ADUs in Seal Beach work well on College Park lots with deep backyards and on Hill properties where a second structure can sit below the main home. We build conventional ADUs with James Hardie siding and work with prefab platforms including Abodu, Cover, Dvele, and Mighty Buildings when a factory build fits the lot and budget better. Either way, the unit gets the same permits, the same written price guarantee, and the same one-year workmanship warranty. ADU Builders in Seal Beach

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.
Brands We Service in Seal Beach
We work with the prefab and modular ADU systems Seal Beach homeowners already research: Abodu, Cover, Dvele, Mighty Buildings, Boxabl, and Plant Prefab. Our site crews handle the foundation, utility hookups, and finish work for every unit we install. See our brands page for details on what each platform offers and where it fits.
Pricing for ADU Company in Seal Beach, CA
| Service | Typical range in Seal Beach |
|---|---|
| Garage conversion | $65,000 – $110,000 |
| Detached ADU (400 sq ft) | $120,000 – $160,000 |
| Detached ADU (750 sq ft) | $180,000 – $240,000 |
| Detached ADU (1,000+ sq ft) | $260,000 – $350,000 |
| Attached ADU / junior ADU | $95,000 – $160,000 |
| Room addition (basic, 200 – 300 sq ft) | $70,000 – $95,000 |
| Room addition (primary suite, 400 – 600 sq ft) | $120,000 – $180,000 |
| Second-story addition | $220,000 – $320,000 |
Seal Beach prices run toward the upper end of these ranges when the job involves coastal-zone review, flood-elevation work, or a variance hearing. You still get one number in writing before any work starts, and that number does not move unless you change the scope.
Neighborhoods We Serve in Seal Beach
We work throughout Seal Beach, from the Old Town bungalows north of Main Street to the hillside homes and down into the College Park tracts. Most estimates are scheduled within a couple of business days, and we keep the same crew on your job from start to finish.
- Old Town
- The Hill
- College Park East
- College Park West
- Bridgeport
Service Area – Cities Near Seal Beach
Fielding ADU Builders serves Seal Beach and the surrounding communities. If you’re just over the border, we also work in Los Alamitos, CA, Cypress, CA, Hawaiian Gardens, CA, and Westminster, CA. Dispatch and scheduling are coordinated from our Los Angeles office; crews serve Seal Beach locally.
Serving Seal Beach, CA - Our Local Coverage Area
We’re based in the Seal 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 ADU Company in Seal Beach

Seal Beach permit review typically runs 4 to 8 weeks for standard ADUs, longer if the property sits in the coastal zone or requires a variance. We start design and structural work immediately after the estimate, so the permit clock and the plan clock run at the same time. Call (361) 315-4177 to get your project in the queue.
Some Seal Beach HOAs, particularly in College Park East and Bridgeport, have architectural review requirements on top of city permits. California law limits what HOAs can prohibit for ADUs, but approval steps still exist. We review your HOA’s CC&Rs during the estimate and flag anything that could delay the job.
Yes. We pull every permit, submit the plans, and manage the inspections through final sign-off. The Garrison Standard means the work is done by the book: permitted, inspected, and documented. You’ll see the permit card posted on-site from day one.
Call (361) 315-4177 for a free estimate and a written price on your Seal Beach ADU, garage conversion, or room addition.
What happens when you call
- 1A real person answersNo phone trees - talk to a local adu pro.
- 2You get an upfront price rangeHonest numbers before anyone is dispatched. No surprises.
- 3We come out and measureLicensed & insured, at a time that suits you - the visit and the quote are both free.
- 4You get the price in writingLine-itemed, yours to keep, and nothing starts until you say go.
What Seal Beach Customers Say
"Room addition over the back patio. Framing is square, windows are tight, and the roofline matches."
- Danny L."Foundation and slab poured on schedule. Crew kept the yard orderly."
- Marian J."Garage conversion with a new bath and kitchenette. Permit was handled by them. Inspection passed first time."
- Sheila B.



