Fast, Reliable New Detached ADU Across Miami
A new detached ADU in Miami typically runs $185,000 to $310,000 all-in, drawings through final inspection, depending on whether you build custom on a slab or specify a prefab system from Cover or Dvele. The Miami-Dade Notice of Acceptance (NOA) requirement for windows, doors, and roofing adds roughly $4,000 to $9,000 in component costs versus a comparable Broward job, and the county’s sewer tie-in trigger can add another $10,000 to $18,000 before framing starts. We’re Ellery ADU Studio, a design-build studio that has put 900+ ADUs through permit and construction since 2015, and we serve Miami homeowners from our South Florida office at (971) 497-2402.
Miami’s housing stock is dominated by 1940s to 1970s concrete block and stucco construction on small lots in neighborhoods like Little Havana, Allapattah, Liberty City, and Little Haiti. The lots are tight, the electrical services are often undersized, and the cast-iron drain lines are frequently at the end of their life. We plan for that from day one.
Why Ellery ADU Studio Is Miami’s Preferred New Detached ADU Company
Miami homeowners come to us because we write the price down before any work begins. Every detached ADU we build in Miami falls under The Haven Standard: a written price before work starts (Clause 1), a documented photo record on every visit, and a 365-Day Done Right Promise stating that if the finished structure doesn’t match the permitted drawings, we make it right at our cost. The designer-versus-builder blame gap that stalls most ADU projects doesn’t exist here. The drawings, the permit set, and the construction are one contract at one price. Nadia Ellery founded the studio in 2015, the year California’s ADU permitting landscape shifted, and she built the practice around the permit set as the core product, not an afterthought.
We’ve seen what happens when a contractor who mostly works Broward drives south. The window package that passed inspection in Fort Lauderdale gets flagged in Miami-Dade because it carries a Florida Product Approval sticker but lacks a Miami-Dade NOA. The inspector pulls it, the job stops, and the homeowner pays for a full swap. We don’t let that happen. When we specify windows, doors, and roof components for a Miami detached ADU, we verify the Miami-Dade NOA before the product is ordered.
Our New Detached ADU Services in Miami
Custom Built ADU
A custom detached ADU in Miami means stick framing or insulated concrete forms on a new slab, with the walls, roof, windows, and doors all spec’d to Miami-Dade NOA standards. We typically see projects in the $210,000 to $310,000 range in Little Havana and Allapattah for a 600 to 800 square foot one-bedroom unit. The space between what you want and what Miami-Dade’s zoning allows is where a documented permit set matters. We handle the setback variance, the lot coverage calculation, and the window schedule with the county’s requirements baked in from the first drawing.
Prefab ADU Installation
We specify and coordinate prefab systems from Cover, Dvele, Mighty Buildings, and Boxabl within the same single contract. A prefab detached ADU in Miami typically runs $185,000 to $260,000 including site work, foundation, utility connections, and the crane or panel delivery. The catch in Miami is that the factory-built shell still needs Miami-Dade NOA components at the site level, and the foundation has to account for oolitic limestone with a water table 2 to 4 feet below grade. We coordinate the factory drawings against the Miami-Dade permit review so the prefab unit doesn’t arrive with the wrong window package.
Modular ADU
Modular construction suits Miami’s tight lots in neighborhoods like Liberty City and Little Haiti, where crane access is limited and the side yard is six feet wide. Our New Detached ADU team handles modular units as a full design-build scope: the module order, the site prep, the utility tie-ins, and the final trim. Expect $195,000 to $275,000 for a modular one-bedroom in Miami, with the electrical service upgrade and sewer connection handled before the modules arrive. That sequencing prevents the two-week delay and rework that happens when a module is set before the panel is upgraded.
Studio ADU
A studio detached ADU in Miami, typically 350 to 500 square feet, runs $150,000 to $220,000. We build a lot of these in Little Havana and Allapattah as legalized replacements for informal backyard efficiencies that have been there for decades. The smart move with a Miami studio ADU is to size the mini-split for full-load, year-round cooling, specify Miami-Dade NOA double-hung windows, and put the 200-amp panel in the scope from the start. Cutting any of those three line items to save money creates a failure that shows up within the first Miami summer.
1-Bed & 2-Bed ADU
A one-bedroom detached ADU in Miami typically lands at $190,000 to $270,000. A two-bedroom runs $240,000 to $330,000. The difference is mostly square footage, but in Miami it also means a second mini-split zone, additional Miami-Dade NOA window units, and sometimes a larger water heater. We write the allowance for the electrical upgrade, the repipe, and the sewer tie-in as line items in the contract, not as vague contingencies that get eaten before framing.
What happens when you call
- 1
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 Miami
We specify and coordinate Cover service in Miami, Dvele, and Mighty Buildings systems on Miami detached ADUs. Our approach is practical: we bring the brand in when the site, budget, and permit timeline support it, and we handle the site work, foundations, utility connections, and Miami-Dade NOA compliance on our end. You don’t get handed off between a factory rep and a general contractor. One contract covers the whole thing.
Common New Detached ADU Problems We See in Miami Homes
- Miami-Dade NOA window failures. A contractor specifies windows with a standard Florida Product Approval sticker, the Miami-Dade inspector pulls them, and the homeowner pays for a full swap plus re-inspection. We verify the NOA before ordering.
- Mandatory sewer tie-in surprises. Lot sits in a neighborhood where the county requires municipal sewer connection for any new ADU, and the $10,000 to $18,000 cost wipes out the contingency. We check the sewer trigger during due diligence, before the contract is signed.
- Undersized mini-splits. A seasonal-climate rule of thumb says two tons is fine, but Miami’s Climate Zone 1A full-load cooling means the unit short-cycles, fails to dehumidify, and trips breakers within months. We size for Miami’s actual load, not a national average.
- Deteriorated cast-iron and undersized panels in CBS homes. Opening up a 1950s concrete block home in Little Havana or Allapattah regularly reveals original 100-amp service and cast-iron drain lines that have rotted through. A certificate of occupancy won’t be issued until both are brought current, so we write them into the scope up front.
Pricing for New Detached ADU in Miami, FL
A detached ADU in Miami runs $150,000 to $330,000 depending on size, system type, and what the existing house needs. Here are the line-item ranges we see on Miami jobs:
| ADU Type | Typical All-In Range (Miami) |
|---|---|
| Studio ADU (350-500 sq ft) | $150,000 - $220,000 |
| 1-Bedroom ADU (500-800 sq ft) | $190,000 - $270,000 |
| 2-Bedroom ADU (800-1,000 sq ft) | $240,000 - $330,000 |
| Prefab/Modular (any size) | $185,000 - $275,000 |
| Miami-Dade NOA window/door package | $4,000 - $9,000 adder |
| Mandatory sewer tie-in (if triggered) | $10,000 - $18,000 adder |
| 200-amp panel upgrade (typical) | $4,500 - $7,500 |
Every one of these numbers goes into a written quote before work starts, per Haven Standard Clause 1. No change orders appear at the door. If something opens up that wasn’t visible at signing, the change is priced and approved in writing before we touch it. Call (971) 497-2402 to schedule a walkthrough and we’ll put the full scope on paper.
We Also Serve Cities Near Miami
We handle new detached ADU projects across New Detached ADU in Miami and the surrounding South Florida area, including Miami Beach, Hialeah, Miami Gardens, and North Miami Beach. If you own a single-family lot within 45 minutes of our South Florida office, we can schedule a site walkthrough and write the full scope.
Serving Miami, FL - Our Local Coverage Area
We’re based in the Miami 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 Miami
Miami-Dade County requires a Notice of Acceptance for every window, door, and roof component on a permitted structure, and the county’s inspectors treat the NOA as a separate certification from the Florida Product Approval. A window that passed inspection on a Broward ADU last month will be flagged and pulled in Miami-Dade if it lacks the NOA. We verify the NOA on every component before ordering, and we line-item the cost difference in the contract up front. Call (971) 497-2402 for a written scope that includes the correct window package the first time.
Possibly, and it depends on the specific lot. Miami sits on oolitic limestone with a water table 2 to 4 feet below grade, so basements are impossible and new ADUs that require septic work often trigger a mandatory municipal sewer connection. That connection typically runs $10,000 to $18,000 before framing. We verify the trigger during due diligence and put the number in writing before you sign anything. Call (971) 497-2402 and we’ll check your lot’s status as part of the free estimate.
We write allowances into the contract for the known unknowns: the undersized 100-amp panel, the cast-iron drain lines, and the sewer tie-in if the lot triggers it. When we open a wall and find something worse than the allowance covers, the change is priced and approved in writing before we continue. That’s Haven Standard Clause 5: no door-side upsells. Call (971) 497-2402 and we’ll walk the house with you and our inspection report before we write the quote.
Yes, and a meaningful share of our Miami work is exactly that: code-remediation and legalization of structures that have been informally housed for years. The process involves a full electrical and plumbing evaluation, a Miami-Dade NOA window and door package, a permitted sewer tie-in if required, and a final inspection that issues the certificate of occupancy. We recently opened up a Little Havana efficiency and found original 100-amp service, rotted cast-iron drains, and window units feeding off one circuit. Our fix: a 200-amp panel, a full repipe, a permitted sewer connection, NOA-rated double-hung windows, and a sealed mini-split sized for full-time Zone 1A cooling. Call (971) 497-2402 to have us evaluate the existing structure and write the legal path forward.
Miami is Climate Zone 1A, which means the cooling load is essentially full-time and year-round. A mini-split sized on a seasonal-climate rule of thumb short-cycles, fails to dehumidify, and trips breakers within months of installation. We size the system for Miami’s actual latent and sensible load, and we document the load calculation in the permit set. Call (971) 497-2402 and we’ll include the correct specification in your written quote.
Written by Nadia Ellery, Owner at Ellery ADU Studio, serving Miami since 2015.
Call (971) 497-2402 to schedule your free estimate. A live person answers, and every project gets a written price before any work begins.