Cost to Build an ADU in Florida2026 Complete Breakdown: $40K–$320K
Garage conversions start around $40K. New detached ADUs run $150K–$320K. Here is the full cost breakdown by ADU type, Florida city, and what drives the range.
How much does an ADU cost in Florida?
Florida ADU construction costs in 2026 range from $40,000–$80,000 for a garage conversion to $150,000–$320,000 for a new detached ADU. The typical all-in cost for a 600 sq ft detached ADU — including permits, impact fees, and site work — is $170,000–$220,000 in Central Florida, and $210,000–$310,000 in South Florida (HVHZ wind zone).
ADU Cost Per Square Foot in Florida
North Florida
$180–$230/sq ft
Jacksonville, Gainesville, Tallahassee — lowest labor costs in the state
Central Florida
$200–$260/sq ft
Orlando, Tampa, Lakeland — standard wind zone, moderate labor
South Florida (HVHZ)
$260–$350/sq ft
Miami, Fort Lauderdale, West Palm — hurricane-rated construction required
These are hard construction costs only — the per-square-foot rate your general contractor charges. Add permits ($3K–$8K), impact fees ($8K–$25K), site prep ($5K–$15K), and design ($5K–$12K) to get an all-in number. The bigger the ADU, the lower the effective $/sq ft — fixed costs (permits, foundation, utility hookup) spread across more area.
ADU Cost by Type
| ADU Type | Cost Range | Typical Size | Build Time | Notes |
|---|---|---|---|---|
| Garage ConversionCheapest | $40K – $80K | 300–600 sq ft | 3–5 months | Cheapest path. No foundation. Add 25% for HVHZ (South FL). |
| Attached ADU (Addition) | $80K – $180K | 400–800 sq ft | 5–8 months | Shares a wall with main house. Foundation required for new footprint. |
| Detached ADU (New Build) | $150K – $320K | 400–1,000 sq ft | 8–14 months | Full new structure. Highest cost, most value added, most flexibility. |
| Prefab / Modular ADU | $90K – $200K | 400–800 sq ft | 4–7 months | Faster build time. Site prep and foundation costs still apply. |
Ranges are all-in estimates including permits, impact fees, and site work. Hard construction costs only are 15–25% lower.
What Makes Up the Cost: Line-Item Breakdown
For a typical 600 sq ft new detached ADU in Central Florida (standard finishes, no HVHZ), here is where the money goes.
ADU Construction Cost by Florida City
Labor rates, impact fees, and wind zone requirements vary significantly across Florida. South Florida's High Velocity Hurricane Zone (HVHZ) adds 20–30% to construction costs versus Central Florida.
| City | All-In Range (600 sq ft) | Labor Cost | Impact Fees | Wind Zone |
|---|---|---|---|---|
| Jacksonville | $130K – $230K | Low | $8K–$12K | Standard |
| Gainesville | $120K – $210K | Low | $5K–$10K | Standard |
| Orlando | $150K – $260K | Medium | $8K–$15K | Standard |
| Tampa | $160K – $280K | Medium | $12K–$20K | Standard |
| Sarasota | $170K – $290K | Medium-High | $10K–$18K | Partial HVHZ |
| Fort Lauderdale | $190K – $320K | High | $15K–$25K | HVHZ |
| West Palm Beach | $180K – $310K | High | $15K–$22K | HVHZ |
| Miami | $200K – $340K | High | $20K–$30K | HVHZ |
HVHZ = High Velocity Hurricane Zone (Broward, Miami-Dade, parts of Palm Beach). Hurricane-rated windows, doors, and roofing are required by code and add $20K–$50K to a detached ADU.
5 Factors That Drive the Cost Range
Wind Zone (HVHZ vs. Standard)
Broward, Miami-Dade, and most of Palm Beach County fall inside Florida's High Velocity Hurricane Zone. HVHZ construction requires impact-resistant windows ($8K–$15K premium), reinforced roof attachments, and structural upgrades that add 20–30% to total costs versus Central Florida.
Foundation Type
Florida's flat terrain typically allows slab-on-grade foundations, which are the cheapest option ($12K–$20K). Properties in FEMA flood zones may require elevated foundations — adding $15K–$40K depending on the required elevation. Check your property's flood zone on FEMA's Flood Map Service Center before budgeting.
Detached vs. Garage Conversion
A garage conversion reuses an existing structure — no new foundation, no new roof, no new framing. The savings are substantial: $70K–$140K less than a comparable new detached build. The constraint is that you need a qualifying garage with sufficient square footage.
Finish Level
Basic finishes (vinyl plank flooring, stock cabinets, standard fixtures) add $20K–$35K to hard costs. Mid-range finishes (tile, quartz, semi-custom cabinets) add $35K–$55K. High-end finishes (hardwood, custom cabinetry, designer fixtures) can add $60K–$100K+. For a rental ADU, mid-range finishes typically offer the best ROI.
Septic vs. Sewer
Properties on municipal sewer have lower ADU utility connection costs ($3K–$8K). Properties on septic must evaluate whether their existing system can handle the additional dwelling unit — and often need a tank upsizing or new secondary drain field ($8K–$25K). Get a septic evaluation before finalising your ADU budget.
Is a Florida ADU Worth the Investment?
At current Florida rental rates, a new detached ADU typically achieves a 7–9% cash-on-cash return and a 10–14 year payback period. Rental income in major Florida metros for a 1BR/1BA ADU (600–800 sq ft):
Miami
$1,900–$2,400/mo
Orlando
$1,400–$1,900/mo
Tampa
$1,500–$2,000/mo
Jacksonville
$1,200–$1,600/mo
A $180,000 ADU (mid-range detached, Central Florida) renting for $1,600/month generates $19,200/year gross. After vacancy, maintenance, and taxes, net income is typically $14,000–$16,000/year — a 7.8–8.9% cash-on-cash return. Property value also increases: properties with ADUs in Tampa, Orlando, and Jacksonville sell for $40K–$80K more than comparable properties without.
First step: confirm your address qualifies
Before budgeting construction costs, verify your zoning allows an ADU. Takes 30 seconds.
Check My AddressHow Much Does a 1,000 Sq Ft ADU Cost in Florida?
A 1,000 sq ft detached ADU is the maximum size permitted by right under Florida SB-48 — no city can restrict below this threshold. It's also the most common size homeowners budget for. Here's what it actually costs, all-in, across Florida in 2026:
| Region | Hard Construction | Permits + Impact Fees | All-In Total |
|---|---|---|---|
| North FL (Jacksonville, Gainesville) | $200K–$240K | $11K–$20K | $215K–$265K |
| Central FL (Orlando, Tampa, Lakeland) | $220K–$260K | $16K–$28K | $240K–$295K |
| South FL (Miami, Fort Lauderdale, West Palm) | $270K–$330K | $20K–$35K | $295K–$370K |
The biggest cost driver is wind zone. South Florida (Broward, Miami-Dade, Palm Beach) sits in the High Velocity Hurricane Zone (HVHZ), requiring impact-rated windows, doors, and roofing — adding $40K–$60K on a 1,000 sq ft build vs. Central or North Florida.
1,200 sq ft: Some municipalities allow up to 1,200 sq ft by special exception. Expect to add $25K–$45K to the figures above (roughly $220–$250/sq ft for the additional 200 sq ft), plus any additional impact fees the jurisdiction charges for the larger unit.
Real ADU Project Cost Examples (Florida, 2025–2026)
These are anonymized examples from actual Florida ADU projects completed in 2025–2026. All figures are final invoiced costs including permits, impact fees, and site work.
Garage Conversion — Orlando (Orange County)
Lowest CostSize
480 sq ft
ADU type
Garage conversion (detached)
Zoning
R-1A / standard residential
Hard construction
$48,200
Permits + impact fees
$7,400
Design / drawings
$3,800
Total all-in
$59,400
Timeline
4 months from permit approval
Outcome: Renting for $1,350/month. Break-even at 44 months.
Detached New Build — Tampa (Hillsborough County)
Size
700 sq ft
ADU type
Detached, slab-on-grade
Zoning
RS-50 / standard residential
Hard construction
$154,000
Permits + impact fees
$19,200
Site prep + utilities
$11,500
Design / architect
$8,000
Total all-in
$192,700
Timeline
11 months total (3 mo permitting + 8 mo build)
Outcome: Renting for $1,700/month. Projected 8.5-year break-even.
Attached ADU (Addition) — West Palm Beach (Palm Beach County)
Size
550 sq ft
ADU type
Attached addition, shared wall
Zoning
RS / HVHZ wind zone
Hard construction
$138,000
HVHZ hurricane upgrades
$24,000
Permits + impact fees
$18,600
Design / engineer
$9,200
Total all-in
$189,800
Timeline
7 months (longer permitting due to HVHZ review)
Outcome: Owner occupying; not rented. Appraised value increase: ~$145,000.
Examples are anonymized real projects. Costs will vary based on contractor, finishes, site conditions, and permit timing.
Frequently Asked Questions
How much does it cost to build an ADU in Florida?
Florida ADU construction costs range from $40,000–$80,000 for a garage conversion to $150,000–$320,000 for a new detached ADU in 2026. The typical all-in cost for a 600 sq ft detached ADU — including permits, impact fees, and site work — is $170,000–$220,000 in Central Florida and $210,000–$310,000 in South Florida (HVHZ wind zone).
What is the cheapest way to add an ADU in Florida?
A garage conversion is the cheapest ADU path in Florida at $40,000–$80,000. You skip foundation costs and the structure already exists. Main costs are HVAC, insulation, electrical upgrades, plumbing, and a bathroom addition. In Broward County (HVHZ), add 25% for hurricane-resistant windows and doors.
Do ADU impact fees apply in Florida?
Yes. Florida cities charge transportation, school, and utility impact fees on new ADU construction. These vary: Orlando charges $8,000–$15,000; Tampa charges $12,000–$20,000; Miami-Dade can exceed $25,000 for a detached unit. Impact fees are paid at time of building permit issuance, in addition to permit fees.
Is building an ADU in Florida worth it?
For most Florida homeowners, yes. A $180,000 detached ADU renting for $1,600/month generates $19,200/year gross — a 7–9% cash-on-cash return after expenses. Property value also increases $40,000–$80,000 in major Florida markets. Break-even at typical rents is 8–12 years.
What are ADU construction costs per square foot in Florida?
Florida ADU construction costs $200–$350 per square foot for new detached construction in 2026. Central Florida (Orange, Hillsborough, Pinellas counties) typically runs $200–$260/sq ft for standard finishes. South Florida (HVHZ) runs $260–$350/sq ft. A 600 sq ft ADU at $230/sq ft = $138,000 in hard costs before permits, impact fees, and site work.
How much does a 400 sq ft ADU cost in Florida?
A 400 sq ft ADU in Florida costs $80,000–$145,000 all-in for a new detached build in 2026. Hard construction at $200–$260/sq ft runs $80,000–$104,000 before permits ($3,000–$5,000), impact fees ($5,000–$12,000), and site prep ($4,000–$8,000). Total all-in in Central Florida: $92,000–$129,000. In South Florida HVHZ counties (Miami-Dade, Broward, Palm Beach), add 25–30%: $115,000–$145,000. A 400 sq ft build fits a studio or one-bedroom layout and is the smallest practical new detached ADU. A garage conversion at this footprint costs $40,000–$65,000 — the cheapest path to a finished ADU.
How much does a 1,000 sq ft ADU cost in Florida?
A 1,000 sq ft detached ADU in Florida costs $200,000–$350,000 in 2026. At the Florida average of $220–$250/sq ft for a mid-grade build, expect $220,000–$250,000 in hard construction costs before permits ($3,000–$8,000), impact fees ($8,000–$25,000 depending on city), and site prep ($5,000–$20,000). In South Florida HVHZ counties (Miami-Dade, Broward, Palm Beach), add 25–30%, bringing the total to $280,000–$350,000. A 1,000 sq ft ADU is the maximum size permitted by right under Florida SB-48 — no municipality can restrict ADU size below 1,000 sq ft on eligible residential parcels.
Related Guides
Sources & Methodology
- Florida Statutes §163.31771 — Accessory Dwelling Units
- Cost ranges based on contractor quotes sourced from Florida ADU builders in Hillsborough, Orange, Broward, and Duval counties, Q1 2026.
- Impact fee schedules sourced directly from city/county fee schedules: City of Orlando, City of Tampa, City of Jacksonville, Broward County, Miami-Dade County.
- Rental comparables sourced from Zillow Rent Estimate and Rentometer for 1BR/1BA units under 800 sq ft in each city, Q1 2026.
Cost estimates are ranges for planning purposes. Get a minimum of three contractor quotes for your specific project. Construction costs change with material prices and labor availability.