ADU in Miami, FL
An ADU in Miami, FL typically costs $85,000-$350,000 all-in depending on whether you’re converting an existing garage, building new on a concrete slab, or legalizing a backyard efficiency that’s been occupied for years. Miami-Dade County layers a Notice of Acceptance (NOA) requirement on every window, door, and roof assembly, which pushes material costs above what most national calculators show. We handle the permit set, the build, and the documentation under one contract at one written price. Call (971) 497-2402 for a written quote.
Why Miami Homes Are Different
Most of Miami’s single-family housing stock dates to the 1940s through 1970s: concrete block and stucco homes in Little Havana, Allapattah, Liberty City, and Little Haiti that are structurally capable of carrying an ADU but frequently hide undersized 100-amp electrical panels and original cast-iron drain lines. Those lines have to be replaced before Miami-Dade will issue a certificate of occupancy, and the panel usually has to go to 200 amps. That’s not a bureaucratic footnote; it’s a real line item that shows up on every honest estimate.
Then there’s the ground itself. Miami sits on porous oolitic limestone with a water table two to four feet below grade. No basements, ever. If your ADU plan calls for a new septic connection, the county will almost always mandate a municipal sewer tie-in instead, and that can run past $10,000 before a single wall is framed. The heat and humidity of Climate Zone 1A also mean mini-splits on detached ADUs must be sized for essentially year-round full load. An undersized unit that would pass unnoticed in a seasonal climate fails within the first Miami summer.
Our Main Miami Services
Most Miami homeowners come to us for one of two projects: converting an existing garage into a rentable unit, or building a new detached ADU in the backyard. Both start with the same question: what will the county actually approve on this lot?
Garage Conversion ADU in Miami
Converting a Miami garage means working with the existing slab, which is usually 4 inches thick and often within tolerance for a conversion, but the walls and roof almost never carry a Miami-Dade NOA until we specify replacements. We’ve converted garages in Allapattah where the electrical service had to be rebuilt before the first inspection. Our full breakdown of costs, timelines, and documentation lives on the Garage Conversion ADU in Miami page.
New Detached ADU in Miami
A new detached ADU in Miami is a ground-up build on a slab poured over limestone, with hurricane-rated openings specified from the first drawing. The water table and sewer tie-in rules shape the site plan more than most homeowners expect, and we document every soil test and utility locator ticket. Read the full scope on our New Detached ADU in Miami page.
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.
ADU Design & Permitting in Miami
ADU Design & Permitting in Miami is where projects either get built or die. The single biggest differentiator is the Miami-Dade Notice of Acceptance: every window, door, and roof assembly on your ADU must carry a county-specific NOA number, not just a Florida Product Approval sticker. Contractors who do most of their work in Broward get rejected at Miami-Dade inspections for exactly this reason: the same window unit that passed last month in Broward gets flagged and pulled here. Our permit set names the specific NOA-compliant product for every opening before you sign a construction contract, and we build from those drawings, not around them. Our ADU Design & Permitting work includes the site assessment, the blueprints, the permit application, and every HOA and zoning compliance packet Miami requires.
Site Assessment
Signs you need it
You’re unsure whether your Little Havana or Liberty City lot can carry an ADU given the setback, water table, and sewer line location.
What it costs in Miami
A site assessment for an ADU in Miami typically runs $400-$1,200 depending on whether we need a surveyor’s boundary check and soil boring.
How we do it
We pull the county’s parcel data, walk the lot with a laser measure, locate the existing sewer lateral, and write the findings into a one-page report you keep.
Permit Application
Signs you need it
You’ve heard a neighbor’s ADU permit got bounced at Miami-Dade for a window spec, and you don’t want to be the second one on that block.
What it costs in Miami
Our full permit application package, including the NOA compliance review, runs $3,500-$8,000 as part of the design contract, depending on the site’s zoning history.
How we do it
We assemble the architectural set, the structural pages, the NOA product schedule, and the energy compliance forms, then submit as one package and track every comment.
What ADU Design & Permitting Costs in Miami
| Item | Typical range in Miami |
|---|---|
| Site assessment and report | $400 - $1,200 |
| Full design and permit set | $8,000 - $25,000 |
| NOA compliance review and product spec | $1,500 - $4,000 |
How long does ADU permitting take in Miami?
Permit review in Miami-Dade generally takes three to six months depending on the zoning district and whether your property triggers HOA review. A clean NOA-compliant submittal moves faster. Call (971) 497-2402 for a written timeline based on your address.
What do ADU blueprints in Miami have to include?
They must include Miami-Dade NOA numbers for every window, door, and roof assembly, plus structural pages stamped by a Florida-licensed engineer. Without the NOA schedule, the application gets rejected before review begins. Call (971) 497-2402 for a written permit-set scope.
Junior ADU & Interior Conversion in Miami
Junior ADU & Interior Conversion in Miami usually means legalizing a space that already functions as a unit: a converted garage suite, an enclosed porch in Little Haiti, or a backyard efficiency that’s been rented informally for years. Miami’s Cuban, Haitian, and Caribbean neighborhoods have housed informal backyard efficiencies for generations, so a large share of the Miami ADU market is actually legalization and code remediation of already-occupied structures. That means our first job is confirming what exists, then drawing the path to a certificate of occupancy without tearing down what’s still sound. Our Junior ADU & Interior Conversion work covers attached additions, room conversions, and interior JADUs under one written price.
Room-to-ADU Conversion
Signs you need it
You have an attached bonus room, enclosed porch, or carport conversion that someone is already living in, and you want it legal and insurable.
What it costs in Miami
Interior room-to-ADU conversions in Miami typically run $60,000-$140,000 depending on whether we’re adding a kitchenette, a separate entrance, or a new electrical circuit.
How we do it
We document the existing framing and electrical, write the plan for the required life-safety upgrades, then build and permit the unit as one scope.
Attached Addition ADU
Signs you need it
Your lot’s setback rules leave no room for a detached unit, but the side yard along your existing home can carry a properly designed addition.
What it costs in Miami
Attached addition ADUs in Miami run $150,000-$300,000 because the tie-in to the existing roof and foundation carries structural work most conversions don’t.
How we do it
We design the addition to match the existing roofline, specify NOA-compliant ties and openings, and build the connection as part of the original contract.
What Junior ADU & Interior Conversion Costs in Miami
| Item | Typical range in Miami |
|---|---|
| Interior room-to-ADU conversion | $60,000 - $140,000 |
| Attached addition ADU | $150,000 - $300,000 |
| Interior JADU with kitchenette | $45,000 - $90,000 |
Can I legalize an existing backyard apartment in Miami?
Yes, if the structure is sound enough to bring up to current code, including electrical service, egress, and NOA-compliant openings. We document what’s salvageable first, then write the remediation scope. Call (971) 497-2402 for a written assessment.
What is a JADU in Miami?
A Junior ADU is a smaller unit, often 500 square feet or less, carved from an existing home. Miami-Dade treats it as a separate category with its own occupancy rules. Call (971) 497-2402 for a written JADU scope for your property.
ADU Site Prep & Utilities in Miami
ADU Site Prep & Utilities in Miami is where underestimating the ground gets expensive. The oolitic limestone is porous, the water table sits two to four feet down, and a mandatory municipal sewer tie-in can exceed $10,000 before the first wall is framed. Miami’s 1940s-era homes also hide undersized 100-amp panels and original cast-iron drains, and both usually have to go before Miami-Dade will close out the permit. Our ADU Site Prep & Utilities work covers foundation, electrical, plumbing, gas, and grading as one scope with one written price.
Foundation & Grading
Signs you need it
Your backyard is low-lying, holds water after a Miami afternoon storm, or sits on fill that has settled unevenly over the decades.
What it costs in Miami
Foundation and grading for a detached ADU in Miami typically runs $12,000-$35,000 depending on slab size, fill requirements, and soil conditions.
How we do it
We compact and grade the pad, form and pour the slab, install the moisture barrier, and photograph every step for your project record.
Electrical Panel Upgrade
Signs you need it
Your main panel is a 100-amp unit from the 1960s or 1970s, and the ADU will need its own circuits, HVAC, and lighting on top of the existing load.
What it costs in Miami
A 200-amp panel upgrade for an ADU in Miami generally runs $3,500-$6,500, including the new panel, breakers, and county inspection.
How we do it
We size the new service to the ADU’s actual load, replace the panel and grounding, and pull the permit before any wall work starts.
What ADU Site Prep & Utilities Costs in Miami
| Item | Typical range in Miami |
|---|---|
| Foundation and grading | $12,000 - $35,000 |
| Electrical panel upgrade to 200A | $3,500 - $6,500 |
| Municipal sewer tie-in | $8,000 - $15,000 |
Will my ADU in Miami need a sewer tie-in?
If your lot is on septic, yes, almost always. Miami-Dade mandates connection to the municipal sewer for new ADUs on most parcels, and that work alone can exceed $10,000. Call (971) 497-2402 for a written site-plan review.
Do I need a new electrical panel for an ADU in Miami?
Most 100-amp homes from Miami’s 1940s-to-1970s stock cannot support an ADU without a panel upgrade to 200 amps. We include the panel scope in your written price before work starts. Call (971) 497-2402 for a written estimate.
Brands We Service in Miami
We regularly specify and coordinate ADU systems from Cover, Dvele, and Mighty Buildings for Miami projects, with parts sourced from local distributors and matched to Miami-Dade NOA requirements. Turnaround on branded components is typically two to four weeks once the permit set is approved. Full details are on our brands page.
Pricing for ADU in Miami, FL
| Service | Typical range in Miami |
|---|---|
| Site assessment and report | $400 - $1,200 |
| Full design and permit set | $8,000 - $25,000 |
| NOA compliance review and product spec | $1,500 - $4,000 |
| Interior room-to-ADU conversion | $60,000 - $140,000 |
| Attached addition ADU | $150,000 - $300,000 |
| Interior JADU with kitchenette | $45,000 - $90,000 |
| Foundation and grading | $12,000 - $35,000 |
| Electrical panel upgrade to 200A | $3,500 - $6,500 |
| Municipal sewer tie-in | $8,000 - $15,000 |
Costs in Miami push upward when the property needs a sewer tie-in, a NOA-mandated window and door replacement, or a panel upgrade, all of which show up as separate line items in any honest estimate. Every project at Ellery ADU Studio gets a written price before any work begins, per Haven Standard Clause 1.
Neighborhoods We Serve in Miami
We serve Miami homeowners from Little Havana and Allapattah to Liberty City, Little Haiti, and the inner suburban pockets east of the Palmetto. Our crews work these neighborhoods weekly, and we schedule site assessments within two to three business days of your call.
- Little Havana
- Allapattah
- Liberty City
- Little Haiti
- Shenandoah
Service Area - Cities Near Miami
We also serve homeowners in Miami Beach, FL, Hialeah, FL, Miami Gardens, FL, and North Miami Beach, FL. Each of those cities has its own building department and inspection quirks, and we handle the coordination on your behalf as part of the permit set.
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 About ADU in Miami
A conversion typically takes five to nine months from permit to certificate of occupancy, while a new detached ADU runs eight to fourteen months. Permit review at Miami-Dade is the biggest variable. Call (971) 497-2402 for a written timeline based on your address.
Yes, if your property is in a deed-restricted community. Miami-Dade code sets the minimum standards, but HOAs can add their own architectural review requirements that we include in the design phase. Call (971) 497-2402 for a written HOA compliance review.
No. Every Ellery ADU Studio project carries a written scope locked at signing, per Haven Standard Clause 5, with no door-side upsells or scope creep. If we find a buried issue, we document it in writing before any added work is approved.
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 Miami Customers Say
"Garage conversion finished on the drawings and close to the schedule. They were honest that the sewer connection was the unknown, and it was."
- Arjun D."The permit set and the build were one contract with one number. Our neighbours used two firms and spent a year watching them blame each other."
- Helena V."The rental income has covered the payment since the second month. They were realistic about the numbers rather than optimistic."
- Odette N.