Fast, Reliable New Detached ADU Across Jacksonville
A new detached ADU in Jacksonville, FL typically costs $180,000 to $340,000 all-in, drawings through final inspection, with most projects taking 9 to 14 months from first site visit to certificate of occupancy. That range assumes the lot is not in a FEMA AE flood zone. If it is, plan for another $25,000 to $55,000 in foundation work alone. At Ellery ADU Studio, led by Nadia Ellery, every Jacksonville project gets a written price before any work starts, the permit set is treated as the core deliverable, and the drawings, permits, and construction are one contract. Call (971) 497-2402 for a free second opinion on any written estimate you already have.
Why Ellery ADU Studio Is Jacksonville’s Preferred New Detached ADU Company
We have designed, permitted, and built over 900 ADUs since 2015, and the Jacksonville market is its own animal. The 1968 consolidation left Duval County enormous, which means our crews cover everything from the pre-war grid of Avondale to post-war ranches in Arlington and newer lots out near Baymeadows and the Southside. That geographic spread matters because a detached ADU on a 1958 ranch in Riverside faces different code layers than one on a 1990s lot in Mandarin, and we already know which questions the plans examiner will ask before you do.
Every Jacksonville project runs through the same standard: a written price before work begins, per Haven Standard Clause 1, a documented photo record on every site visit, and a 365-Day Done Right Promise in writing. The client sees the permit set before we submit it. We do not ask anyone to trust a friendly handshake on a six-figure build. We hand you the documents. Call (971) 497-2402 and a live person answers. No queue.
Our New Detached ADU Services in Jacksonville
We do not treat New Detached ADU construction as a generic build. Jacksonville’s codes, flood maps, and wind-load requirements shape the design before we ever pour concrete. Here is what that looks like in practice.
Custom Built ADU
For Jacksonville homeowners who want a structure matched to an existing 1950s ranch or a 1920s Avondale bungalow, a custom build gives you full control over roofline, window placement, and interior layout. We design to the lot’s actual setbacks and bring the permit set to the city only after you have approved every sheet. Custom detached ADUs in Jacksonville run $190,000 to $360,000 depending on square footage and foundation requirements.
Prefab ADU Installation
Prefab works well on Jacksonville’s larger suburban lots, particularly in Arlington, Southside, and Mandarin where crane access is straightforward and the setback math is simple. We specify and coordinate systems from Abodu, Cover, and Dvele within the same single contract, which means the prefab manufacturer, the site work, and the foundation are all our responsibility. The written price you sign is the written price you pay. Prefab installation for a detached ADU in Jacksonville typically runs $165,000 to $290,000 all-in.
Modular ADU
Modular construction solves a specific Jacksonville problem: long build seasons interrupted by summer rain and hurricane-watch slowdowns. A module built indoors avoids weather delays on the frame. We have paired Mighty Buildings panelized shells with stem-wall foundations on AE-zone lots where the finished floor had to sit two feet above grade. Modular detached ADUs in Jacksonville run $175,000 to $310,000, with the final number driven by foundation type and utility trenching distance.
Studio ADU
A studio ADU is the most common entry point for Jacksonville homeowners who want rental income or a long-term guest suite without the footprint of a full one-bedroom. On a clear, buildable lot outside the flood zones, a 450 to 600 square foot studio can come in between $150,000 and $220,000 with a kitchenette, bath, and its own mini-split. If the FEMA FIRM panel shows an AE designation, the number moves upward, and we will show you the exact line item before you commit to anything.
What happens when you call
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A real person answersNo phone trees - you reach a local pro.
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You get an upfront price rangeHonest numbers before anyone is dispatched.
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A background-checked tech heads outLicensed & insured, dispatched right away.
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You approve before work beginsNothing starts until you say go.
Trusted Brands We Service in Jacksonville
We specify and coordinate prefab and modular systems from Abodu, Cover, Dvele, Mighty Buildings, and James Hardie, and we do not treat brand selection as an afterthought. The shell you choose has to carry a wind-load rating that matches what Duval County actually enforces under ASCE 7, and the cladding has to survive nine months of humidity. For Jacksonville clients, we lean on panelized and modular shells that arrive with documented product approvals, because your lender and your insurer will both ask for that paperwork eventually. We make sure it exists before the first module leaves the factory.
Common New Detached ADU Problems We See in Jacksonville Homes
- Slab-on-grade quotes on lots that are actually in AE flood zones. A builder walks the backyard, sees flat ground, quotes a slab. Then the FEMA FIRM panel comes back and the whole design has to shift to a stem-wall or pier foundation, adding $25,000 or more after the client already mentally committed to the lower number.
- Wind-load ratings that fail Duval County inspection. A shell gets installed with a generic Florida product approval that does not match Jacksonville’s ASCE 7 risk category. The roof-to-wall connection inspection fails, and now the homeowner is paying for re-engineering on a structure that is already standing.
- Mini-splits sized by square footage alone. Jacksonville’s cooling season runs roughly nine months, and a standalone ADU cannot share the primary home’s HVAC. Installers who ignore latent heat load end up with a unit that cannot hold humidity below 60%, and the drywall grows mold by the first August.
- Historic district surprises in Riverside, Avondale, and Springfield. A standard detached ADU permit gets submitted, then the historic overlay review kicks in and adds a separate approval layer the owner never budgeted for. We pull those overlays before we quote.
Pricing for New Detached ADU in Jacksonville, FL
Here are the numbers we actually quote in Jacksonville, not the vague ranges you see on national sites. A straightforward studio ADU on a clear lot runs $150,000 to $220,000. A one-bedroom detached unit on a standard residential lot runs $185,000 to $280,000. A two-bedroom runs $240,000 to $360,000. If the lot sits in a FEMA AE zone, add $25,000 to $55,000 for a stem-wall or pier foundation and the elevation certificate that goes with it. If the home predates 1970, add $4,000 to $9,000 for a panel upgrade from 100-amp to 200-amp service. Every one of those numbers appears as a line item in a written quote before you sign anything. That is Haven Standard Clause 1, and it is non-negotiable. Call (971) 497-2402 and we will put the numbers on paper.
We Also Serve Cities Near Jacksonville
Our Jacksonville office coordinates detached ADU work across the region, and we regularly run projects in Gainesville, Daytona Beach, Orlando, and Kissimmee. If you are outside Duval County but still want the same New Detached ADU in Jacksonville standard of written pricing and documented permits, call the same number: (971) 497-2402.
Serving Jacksonville, FL - Our Local Coverage Area
We’re based in the Jacksonville 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 - New Detached ADU in Jacksonville
Because Jacksonville’s flat, low terrain and the St. Johns River basin put a large share of residential parcels in FEMA AE or X-500 zones, and a lot that looks like an easy slab-on-grade build on satellite view can require a finished floor 18 to 24 inches above grade. That single finding changes the foundation design from a slab to a stem-wall or pier system and can add $25,000 to $55,000 to the project. We pull the FEMA FIRM panel before we quote, not after you have signed a number based on bad assumptions. Call (971) 497-2402 for an exact quote with the flood map already reviewed.
Jacksonville’s structural inspections enforce ASCE 7 wind-load requirements matched to the structure’s risk category, and Duval County inspectors check roof-to-wall connections against that standard, not against a generic Florida product approval. A compliant quote in Jacksonville includes a shell with documented wind-load ratings, signed engineering, and the connection details on the permit set sheets. A cheaper quote often leaves that documentation for later, and the inspection failure lands on the homeowner. We include it in the written price from the start.
Yes. Riverside, Avondale, and Springfield all carry historic district overlays, which means the detached ADU goes through a separate design review on top of standard Duval County permitting. The review looks at roofline, materials, window proportions, and how the new structure reads from the street. We have put detached ADUs through those overlay reviews in Jacksonville, and the difference between approval and a stalled application is usually whether the drawings were prepared with the overlay standards in mind from sheet one. Call (971) 497-2402 to walk through your specific property.
Because Jacksonville’s nine-month cooling season and extreme humidity mean a detached ADU needs its own independently sized system to handle latent heat load, and tying into the main home’s ductwork creates uneven temperatures, overloaded equipment, and a unit that cannot hold humidity below 60%. We specify a dedicated mini-split or ducted system sized for the ADU’s actual load calculation on every Jacksonville project. It is a line item in the written quote, not an upgrade pitch later.
The lender needs three things: a FEMA elevation certificate showing the finished floor at or above base flood elevation, structural documentation showing the shell meets Jacksonville’s ASCE 7 wind-load standard, and a written construction contract with a fixed price. On a 1960s ranch lot in Arlington, our team pulled the FIRM panel, found the backyard in an AE zone, designed a stem-wall foundation with the finished floor at two feet above natural grade, and paired it with a Mighty Buildings panelized shell rated for 150 mph wind loads. The lender approved the loan once the elevation certificate and wind-load documentation were in hand. That documentation is part of what we deliver, not an add-on. Call (971) 497-2402 for a free second opinion on any written estimate you already have.
Get Your Written Price for a New Detached ADU in Jacksonville
You will get a written price before any work begins. You will get a permit set you can review before submission. You will get a documented photo record on every visit, and a 365-Day Done Right Promise in writing. That is how we work in Jacksonville, from Avondale to Mandarin to the beaches. Call (971) 497-2402 for a free estimate, or to have us review any written estimate you have already received.
Written by Nadia Ellery, Owner at Ellery ADU Studio, serving Jacksonville with written-price ADU design and construction since 2015.
New Detached ADU in Nearby Areas
