Free written scope consultation - allowances, timeline, and change-order rules on paper before a single trade is scheduled
Before
After
Before
After
Before
AfterFast, Reliable Home Additions & ADU Across Marina
Home additions and ADU construction in Marina typically run $45,000 to $130,000 for a room addition, and $90,000 to $220,000 for a new detached ADU. Most projects clear permitting in 8 to 16 weeks, though Marina carries one complication few California towns have: nearly every build sits on former Fort Ord land, which means FORA environmental review before you can even think about footings. We know that process cold because we’ve done it. Call (877) 610-1318 and Tom or one of his sons will walk you through what your specific lot requires.
We’re Barrett & Sons Construction. Crews from our San Francisco Bay Area office work Marina jobs locally, so you’re not waiting on someone driving from three counties away. Whether you’re adding a bedroom near Preston Park, building a detached ADU off Reservation Road, or converting a Fort Ord-era structure off Imjin Parkway, we handle the whole job from first sketch to final inspection.
Why Barrett & Sons Construction Is Marina’s Preferred Home Additions & ADU Company
Tom Barrett founded this company in 1998, and his sons run the crews. That’s not marketing copy. When you call, you get Tom. When the crew shows up at your Marina property, the name on the truck matches the people holding the tools. We publish Tom’s name, address, and license number, and we’ll never be offended if you look them up. Plenty of Marina homeowners do, especially after a bad experience with someone else.
Marina’s building rules are different from anywhere else in Monterey County, and the contractors who thrive here know it. The Fort Ord Reuse Authority environmental process, Monterey County’s special permit path for former base parcels, and the sandy subsoil under nearly every street in 93933 all shape what’s buildable and what it costs. We’ve worked through all of it enough times that the county staff know our paperwork and our work. Reviews from Marina customers consistently mention that our jobs pass inspection the first time and that change orders arrive in writing before work starts. Nobody gets a surprise invoice at the end.
We answer the phone. Always. Not a call center, not a voicemail that disappears for three days. If you have a question about your room addition on Cypress Knolls or a concern about your ADU’s vapor barrier on the north side of town, call and a live person picks up, 24 hours a day, 7 days a week.
Our Home Additions & ADU Services in Marina
ADU Design & Permitting
Before you build an accessory dwelling unit in Marina, the paperwork comes first. We handle the full design and permit package, including the FORA clearance letters and Monterey County planning submittals that Marina lots require. Homes in the Cal State Monterey Bay area often sit on parcels with specific density and setback rules, and our plans get written to pass the first time. A full ADU design and permit package here usually lands between $12,000 and $25,000, depending on scope and soil findings.
Garage Conversion ADU
Converting an attached or detached garage into a living unit is the most cost-effective ADU path for Marina homeowners, typically running $30,000 to $80,000. The big issue in Marina is the existing slab. Garages in post-1994 tract developments were poured at minimum thickness over sandy dune soil, and many don’t meet residential floor insulation and vapor barrier requirements once they become living space. We evaluate the slab first, then build from there. This is also where our Home Additions & ADU experience with Fort Ord-era structures really pays off.
New Detached ADU
A new detached ADU on a Marina lot gives you a clean, code-compliant build with no surprises inside the walls. Expect $90,000 to $220,000 depending on size, finish level, and foundation work. Marina’s sandy subsoil means many detached ADUs need engineered slabs or piers rather than standard footings, and the persistent marine air makes exterior framing corrosion a real concern if the wrong fasteners go in. We spec stainless and coated hardware on every exterior connection.
Junior ADU & Interior Conversion
A junior ADU, or JADU, converts existing interior space like a large bedroom or bonus room into a self-contained unit with its own entrance, kitchenette, and bath. For Marina homes, this is often the fastest path to rental income because there’s minimal new foundation work. These projects typically run $40,000 to $90,000, and in converted Fort Ord housing, we frequently rebuild the plumbing and electrical from the studs out. Marina is also a city where we regularly pair a JADU with Bathroom Remodeling in Marina, since the two jobs share walls, plumbing, and inspections.
When the addition is for a kitchen expansion rather than a sleeping unit, our Kitchen Remodeling in Marina team works the same job site, same schedule, same change-order discipline. One crew running both trades means the schedule doesn’t stretch out while you wait on two different subs.
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 Marina
We install windows and doors from Simonton, Ply Gem, and PGT on our Marina additions and ADUs. These aren’t mystery brands off a van. Every one is a named manufacturer you can research, with published ratings for salt-air performance and energy efficiency, which matters a lot when your house sits a quarter mile from Monterey Bay and the wind never really stops. We size the flashing and sealant details for Marina’s marine air specifically, and we keep the local parts inventory stocked so warranty follow-ups in 93933 happen fast, not six weeks later.
Common Home Additions & ADU Problems We See in Marina Homes
- Sandy dune soil under existing slabs. The ancient aeolian sand under most Marina neighborhoods compacts unevenly and shifts over time. Foundation cracks, sticking doors, and sloping floors are the usual signs, and adding square footage on top of that slab without an engineer’s review is asking for trouble. We pull soil reports on every addition, not just the big ADUs.
- Salt-air corrosion on exposed framing and fasteners. Marina’s constant marine layer deposits salt on everything. Exterior nails, joist hangers, and flashing rust years faster here than they would in Salinas. On every addition, we spec galvanized or stainless hardware, and the difference is visible on the wall before drywall goes up.
- Converted Fort Ord housing with institutional-grade construction. Homes converted from former Army housing often have block walls, steel lintels, and plumbing runs that don’t match modern residential code. A room addition on one of these structures means retrofitting the existing envelope first, or the new build fails inspection on the old work.
- Vapor and moisture issues hidden by the marine layer. Marina rarely gets summer rain, but the humidity stays high year-round from the fog. Skipping a proper vapor barrier under an addition’s floor or behind its siding creates mold and rot inside walls people never see until we open one up.
Pricing for Home Additions & ADU in Marina, CA
A room addition in Marina typically runs $45,000 to $130,000. A garage conversion ADU lands between $30,000 and $80,000. A new detached ADU starts around $90,000 and can reach $220,000 for a two-bedroom with premium finishes. The biggest cost drivers in Marina specifically are soil remediation, foundation type, and the FORA environmental paperwork that precedes most permits. Foundation work on sandy lots pushes costs toward the higher end of every range, and that’s non-negotiable if you want the inspector to sign off. We don’t bid low and change orders you later. Every allowance, every scope item, every price changes goes on paper before the work starts. Call (877) 610-1318 for a free estimate, and we’ll give you a written, line-item number you can compare against anyone.
We Also Serve Cities Near Marina
Our crews work all over the Monterey Bay area: Seaside, Castroville, Salinas, and Monterey. If you’re just outside the 93933 boundary, call us anyway. We schedule multiple Marina jobs per week, and adding a Seaside or Castroville stop to the route rarely costs you a trip charge. See what we do across the region on our Marina page, and if you’re planning a larger home project, we also handle kitchen and bath remodels, roofing, windows, and more throughout Monterey County.
Serving Marina, CA - Our Local Coverage Area
We’re based in the Marina 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 Marina
We can usually start site work in Marina within 4 to 8 weeks after the permit is issued. The permitting timeline itself runs 8 to 16 weeks depending on whether your parcel needs FORA clearance, which most Marina lots do. Call (877) 610-1318 and we’ll give you a realistic start date for your specific lot.
Yes, we handle the full FORA clearance and Monterey County environmental submittals for every Marina project. This includes UXO clearance coordination and contaminated-soil documentation when required. It’s part of the design and permit package we prepare, not a surprise add-on halfway through the job. This process simply doesn’t exist for additions in Seaside or Monterey, and skipping it shuts the project down.
A garage conversion ADU in Marina typically runs $30,000 to $80,000. The price depends on slab condition, electrical service capacity, and whether the existing garage meets current code for insulation and moisture control. Most Marina garage slabs need some work before the conversion starts. Call for a free written estimate and we’ll price your exact garage.
No, not unless you change the scope. Every allowance, every material choice, and every change order is written down and signed before the work happens. If a price changes, you see it on paper first. That’s been the rule since 1998, and it’s why Marina homeowners don’t get end-of-job surprise invoices from Barrett & Sons.
Yes, on every eligible job. Permits pulled, inspections signed. The permit inspector works for you, not for us, and we like it that way. A contractor in Marina who says permits are optional on an addition is putting your whole project at risk. We won’t do it, and we won’t work around it. Call (877) 610-1318 to schedule your free estimate.
Get Your Marina Home Addition or ADU Started Today
If you own a home in Marina, CA, and you’re thinking about adding square footage, building an ADU, or converting part of your house into a rental unit, call Barrett & Sons Construction at (877) 610-1318. We’ll come out, walk your property, look at your soil and your setback lines, and give you a written estimate with real numbers. Free estimates, written change orders, permits pulled, inspections signed, and the 90-Day Done Right Promise on every job. Ask anyone on your street, or look up the license number yourself.
Written by Tom Barrett, Owner at Barrett & Sons Construction, serving Marina since day one of every job we’ve done here.