ADU Cost, Financing & ROI in Miami-Dade County, Florida

Key Takeaways

• Miami-Dade County now permits ADUs on 171,683 eligible single-family properties (per NACo analysis of the county's ADU program), with streamlined pre-approved blueprints cutting permitting timelines and making backyard housing more accessible than ever

• Construction costs range from $80,000 to $200,000+ for new ADUs, with Mesocore's Model E ADU starting at $129k factory MSRP and featuring factory-installed, Intertek-certified MEP systems that eliminate on-site rough-in inspections in many jurisdictions

• Rental income potential reaches $900-$2,200 monthly in Miami-Dade neighborhoods, generating strong ROI despite higher hurricane-zone construction costs and strict building code requirements

• Multiple financing pathways exist including HELOCs with variable rates (check current rates at Bankrate), cash-out refinancing with fixed rates (see current Freddie Mac rates), and specialized options through HFS Financial offering fixed rates from 7.99% with no home equity required

• HVHZ compliance adds costs but protects investment: All Miami-Dade ADUs must meet stringent High-Velocity Hurricane Zone standards with design wind speeds determined by site-specific ASCE 7 wind maps (typically 170-186 mph in parts of Miami-Dade), which Mesocore's robotically welded steel core construction satisfies while reducing on-site labor

• Off-grid solar systems with battery storage can operate independently from the main house in some Miami-Dade jurisdictions, eliminating utility connection fees and ongoing energy costs while qualifying for 30% federal tax credits

• Permitting requires 6-18 months from pre-application through final inspections, but factory-built modular ADUs complete on-site installation in as little as 10 days after permits are secured

What Is an Accessory Dwelling Unit (ADU) in Miami-Dade County?

An Accessory Dwelling Unit is a secondary, self-contained residential structure on the same lot as a primary single-family home. It includes its own kitchen, bathroom, and sleeping area, and can be either attached to or detached from the main residence.

According to Miami-Dade County regulations, detached ADUs are generally limited to 800 square feet of the main home area (whichever is less), with minimum lot size requirements that vary by zoning district. Garage conversions may have different lot size thresholds. All ADUs must comply with Florida Building Code and High-Velocity Hurricane Zone (HVHZ) standards unique to Miami-Dade and Broward counties.

Mesocore's Model E ADU delivers 410 square feet with 1 bedroom, 1 bathroom, and full kitchen—engineered to meet or exceed Miami-Dade's stringent HVHZ wind codes. The unit features five hurricane impact windows, one full lite insulated hurricane impact door, and wind design compliant with Miami-Dade HVHZ requirements, addressing the county's most demanding structural requirements while maintaining factory pricing efficiency.

ADU vs. Guest House: Legal Definitions

The critical distinction lies in regulatory compliance and occupancy rights. ADUs require professional engineered design, building permits, and ongoing Certificates of Use renewed annually in Miami-Dade County. Guest houses without proper permitting cannot be legally rented and may trigger code enforcement actions.

Only property owners can obtain the renewable annual Certificate of Use required for ADU occupancy, and this involves mandatory exterior inspections and compliance verification with county standards.

Miami-Dade HVHZ Requirements for ADUs

Miami-Dade's designation as a High-Velocity Hurricane Zone imposes Florida's strictest building requirements. The Florida Building Code requires site-specific wind design per ASCE 7 wind maps, with Miami-Dade HVHZ areas typically requiring design values in the 170-186 mph range, with all exterior openings requiring impact-resistant windows/doors or approved shutters.

Products must carry Miami-Dade Notice of Acceptance (NOA) or Florida Product Approval (FPA) endorsed "HVHZ Impact Rated." Mesocore's modular steel core is robotically welded and hurricane-rated, with all MEP systems factory-installed and Intertek-certified before delivery, reducing on-site inspection requirements in many jurisdictions.

How Much Does a 500 Sq Ft ADU Cost in Miami-Dade County?

Base construction costs for new ADUs in Florida range from $80,000 to $200,000+ per unit, with significant variation based on construction method, site conditions, and finish quality. Detached ADU costs average $180,833 nationally, while attached ADU costs average $154,400.

For a 500 square foot ADU in Miami-Dade County, total installed costs typically break down as follows:

Factory-Built Modular Options:

• Factory MSRP: $129,000 (Mesocore Model E ADU, 410 sq ft)

• Delivery and crane placement: $3,000-$5,000

• Site preparation and foundation: $5,000-$15,000

• Utility connections: $3,000-$10,000

• On-site finish work and labor: $15,000-$30,000

• Total: $155,000-$189,000

Traditional Stick-Built Construction:

• Design and engineering: $5,000-$8,000

• Permits and impact fees: $1,500-$8,000

• Foundation and site work: $8,000-$20,000

• Framing and structural: $30,000-$50,000

• HVHZ-compliant windows/doors: $8,000-$15,000

• MEP systems: $25,000-$40,000

• Interior finishes: $20,000-$35,000

• Total: $97,500-$176,000 (materials and labor)

Factory Cost vs. Total Installed Cost

The Mesocore Model E ADU factory MSRP of $129,000 includes comprehensive features that would cost significantly more in traditional construction:

Included in Factory Price:

• 6-KW solar system with 14 PV panels

• Two 10 kWh lithium-ion battery storage systems

• Robotically welded modular steel core

• All plumbing rough-in and finishing (factory-installed and tested)

• All electrical wiring including panel (factory-installed and tested)

• Hurricane impact windows and doors

• Complete HVAC system with whole house air circulation

• All appliances including combo washer/dryer

• Luxury vinyl plank flooring

• Kitchen and bathroom cabinets with countertops

Additional Costs Not Included:

• Land purchase

• Site preparation and grading

• 8 concrete foundation piers installation

• Delivery (varies by distance)

• General contractor labor for walls, insulation, flooring installation

• Local utility connections (if not operating off-grid)

• Permitting and administrative fees

• Exterior painting and deck construction

Miami-Dade Permitting and Impact Fees

Permit fees range from $1,500 to $8,000 depending on project valuation, including building, electrical, mechanical, and plumbing permits. Impact fees for roads, fire, police, parks, and education services add to total permitting costs.

The county's Pre-Approved ADU Blueprint Program offers faster permitting by using pre-reviewed designs, potentially reducing approval timelines from months to weeks.

Site Prep Costs for South Florida Soil Conditions

Miami-Dade's high water table, limestone bedrock, and coral rock create site-specific challenges. Standard site preparation costs of $2,000-$10,000 can escalate to $15,000-$25,000 for complex sites requiring:

• Extensive soil testing

• Tree removal and land clearing

• Significant grading and fill material

• Rock removal or drilling through coral

• Flood zone mitigation

Mesocore's concrete pier foundation (8 piers) adapts well to variable South Florida soil conditions, avoiding some costs associated with full slab foundations while meeting HVHZ structural requirements.

Prefab ADU Cost Breakdown: What's Included and What's Not

Modular ADU construction offers significant advantages in Miami-Dade's challenging regulatory environment. Factory-built components arrive with critical systems pre-installed and tested, reducing on-site labor coordination and inspection complexity.

What $129k Factory MSRP Includes

The Mesocore Model E ADU factory price delivers a complete living unit:

Energy Systems:

• Full off-grid 6-KW solar system with 14 PV panels

• Two 10 kWh lithium-ion batteries for energy storage

• Inverter, all wiring, connectors, and racks

• Electric hot water heater (50 gallon)

Structural Components:

• Modular steel core robotically welded and hurricane-rated

• Prefab roof with TPO roofing membrane

• Prefabricated wall panels with LP® Smart Side® cedar siding

• All insulation materials for high R-values

MEP Systems (Factory-Installed and Intertek-Certified):

• All rough-in and finishing plumbing

• All electrical wiring including electrical panel

• Ductless Amana R-32 PTAC heat pump

• Whole house air circulation system with HEPA filter

• LED lighting throughout

Doors and Windows:

• 5 hurricane impact windows

• 1 full lite insulated hurricane impact door

Interior Finishes:

• Smooth finished ceiling panels

• Shiplap interior primed walls

• Interior sliding frosted doors (pre-installed)

• Luxury vinyl plank flooring

• Materials for bedroom full-height closet

Appliances and Fixtures:

• Induction cooktop

• Microwave/convection oven

• Refrigerator/freezer with ice maker

• Fisher Paykel drawer dishwasher

• Combo washer/dryer

• Stainless steel kitchen sink with garbage disposal

• Lioher® kitchen, bathroom, and closet cabinets

• Wilsonart® Thinscape® counters

Installation Support:

• Approved engineered construction drawings

• Ships as 20' HC ISO-certified container

Additional Costs: Site Work, Labor, and Utilities

Budget for these essential costs beyond the factory price:

Site Infrastructure:

• 8 concrete foundation piers: $4,000-$8,000

• Site grading and preparation: $2,000-$15,000

• Septic system installation (if needed): $5,000-$15,000

• Water well (if needed): $8,000-$20,000

Labor and Installation:

• Wall installation: $3,000-$6,000

• Window and door installation: $2,000-$4,000

• Flooring installation: $1,500-$3,000

• Insulation installation: $1,500-$3,000

• Interior painting of shiplap walls: $1,500-$3,000

• Exterior painting and trim: $2,000-$4,000

• Porch/deck construction: $3,000-$8,000

Utilities and Connections:

• Electric connection: $1,000-$3,000 (if not fully off-grid)

• Water connection: $1,000-$3,000 (if not using well/rainwater)

• Sewer connection: $2,000-$8,000 (if not using septic)

Administrative:

• Site plan creation: $200-$500

• Permitting: $1,500-$8,000

• Land impact fees: Variable by location

Prefab vs. Stick-Built ADU Costs in Miami-Dade

Factory-built modular construction reduces total build timelines from 8-18 months to as little as 10 days for on-site installation after permits are secured. The elimination of rough-in inspections for factory-installed, Intertek-certified MEP systems further accelerates approvals in many jurisdictions.

Traditional stick-built ADUs require coordinating multiple subcontractors for electrical, plumbing, HVAC, and finish work, with each trade subject to separate inspections and weather delays common in South Florida's climate.

ADU Financing Options: Loans, HELOCs, and Lender Programs

Miami-Dade homeowners can access multiple financing pathways in 2025, each suited to different equity positions and financial profiles.

Home Improvement Loans vs. Renovation Loans

Most traditional lenders—banks and credit unions—finance ADU projects as home improvement loans. These typically require 20-25% down payment and use current home value as collateral.

HELOCs (Home Equity Lines of Credit) offer variable rates—check current HELOC rates at Bankrate for South Florida lenders. Cash-out refinancing provides fixed rates—see current 30-year fixed rates from Freddie Mac for ADU projects, though this replaces your existing mortgage.

Renovation loans combine purchase and improvement financing into a single package, useful for buyers planning to add an ADU immediately after acquiring a property.

HFS Financial: ADU-Specific Financing Partner

HFS Financial provides personal loans from $1,000 to $300,000 with no home equity or appraisal required. Their program features:

• 100% upfront contractor funding

• Fixed rates starting at 7.99%

• Terms up to 20 years for loans over $15,000

• Instant pre-qualification

• No dealer fees for Miami-area contractors

• Specialization in home improvement and ADU financing

This option works well for homeowners with limited equity or those who prefer not to tap existing home value.

Ocean Capital: ADU-Specific Financing Partner

Mesocore partners with Ocean Capital Lending to offer programs designed specifically for ADU projects. Ocean Capital provides financing that covers land, construction cost, and converts into a mortgage, streamlining the funding process for modular home buyers.

Their ADU-specific lending understands the unique requirements of factory-built modular construction and can structure draws around delivery and installation milestones rather than traditional construction phases.

Typical ADU Loan Rates in South Florida

Financing rates in Miami-Dade vary by market conditions and individual credit profiles. As of early 2025, typical ranges include:

• HELOCs: Variable rates (check current Bankrate HELOC rates)

• Cash-out refinancing: Fixed rates (see Freddie Mac PMMS for current 30-year averages)

• Construction loans: 6.75-7.5% with 10-20% down

• HFS personal loans: 7.99%+ fixed

• Traditional home improvement: 7-10% depending on credit

Most lenders require 20-25% down payment and maintain loan-to-value ratios around 80% for ADU construction projects.

Calculating ADU ROI: Rental Income and Property Value Increase

Miami-Dade's strong rental market creates compelling ROI despite higher construction costs and strict hurricane requirements.

Average ADU Rental Rates in Miami-Dade Neighborhoods

Typical ADU rents in Miami-Dade range from $900 to $2,200 per month depending on size and location. A 400-500 square foot unit in mid-tier neighborhoods commands $1,600-$1,900 monthly, while premium areas reach $2,000-$2,200.

Rental Income Scenarios:

• Budget scenario: $900/month × 12 = $10,800 annual gross income

• Mid-range scenario: $1,600/month × 12 = $19,200 annual gross income

• Premium scenario: $2,200/month × 12 = $26,400 annual gross income

Subtract 20% for operating expenses (property taxes, insurance, maintenance, vacancy):

• Budget net: $8,640 annually

• Mid-range net: $15,360 annually

• Premium net: $21,120 annually

How ADUs Increase Home Resale Value

ADUs typically add approximately 100 times monthly rental value to property worth. A $1,600/month ADU increases property value by roughly $160,000, while a $2,200/month unit adds $220,000.

Property value appreciation represents a significant component of total ROI beyond rental income alone.

ROI Timeline: Break-Even Analysis

A Mesocore ADU with total installed cost of $165,000 generating $1,600 monthly rent ($19,200 gross, $15,360 net annually) produces a 10.7-year payback period on cash investment.

The same unit at $2,000 monthly rent ($24,000 gross, $19,200 net annually) reduces payback to 8.6 years.

Including property value appreciation of $160,000-$220,000, total ROI reaches 97-133% before accounting for ongoing rental income streams.

Miami-Dade County ADU Permitting and Zoning Requirements

The permitting process for ADUs in Miami-Dade takes 6-18 months and involves multiple steps: pre-application, professional design, permit application/review, and construction with staged inspections.

Step-by-Step Permitting Process

Phase 1: Pre-Application (2-4 weeks)

• Confirm property eligibility and zoning

• Verify lot size meets minimum requirements per your zoning district

• Review setback requirements

• Check HOA restrictions if applicable

Phase 2: Design and Engineering (4-8 weeks)

• Engage Florida-licensed architect or engineer

• Develop construction drawings

• Obtain structural calculations

• Consider Pre-Approved ADU Blueprint Program for faster approval

Phase 3: Permit Application (8-16 weeks)

• Submit complete application with engineered plans

• Pay permit fees ($1,500-$8,000)

• Respond to plan review comments

• Obtain building, electrical, mechanical, plumbing permits

Phase 4: Construction and Inspections (12-40 weeks traditional, 2-4 weeks modular installation)

• Foundation inspection

• Framing inspection

• MEP rough-in inspections (eliminated for factory-certified modular units in some jurisdictions)

• Final inspection

• Obtain Certificate of Occupancy

Phase 5: Certificate of Use (2-4 weeks)

• Apply for annual renewable CU (property owners only)

• Pass exterior inspection

• Maintain compliance for annual renewals

Mesocore provides stamped drawings, structural calculations, and manages permit submittals for Miami-Dade building departments, eliminating the need to separately engage architects or engineers for design development.

Common Zoning Challenges in Miami-Dade

According to Miami-Dade County regulations, detached ADUs are generally limited to 800 square feet of main home area (whichever is less), which constrains design options. Properties in HOA communities may face additional restrictions beyond county requirements.

Minimum 1-month leases prohibit vacation rentals and Airbnb-style short-term use, limiting income strategies compared to other markets.

HOA Restrictions and How to Navigate Them

Contact your local HOA before investing in design or permitting. Some associations prohibit ADUs entirely through deed covenants, while others impose stricter architectural standards than county code.

Mesocore's customizable exterior finishes—painted vertical siding with optional architectural trim, roof slopes, and awnings—can be adapted to match HOA aesthetic requirements and blend with existing neighborhood character.

Hurricane-Resistant ADU Construction in Miami-Dade's HVHZ

All High-Velocity Hurricane Zone construction in Miami-Dade must withstand design wind speeds determined by site-specific ASCE 7 wind maps (typically in the 170-186 mph range in Miami-Dade). These requirements add 15-25% to construction costs but protect property value and reduce insurance premiums over time.

Why HVHZ Compliance Matters for Insurance

Miami-Dade County homeowners insurance averages $10,419 to $16,823 annually, compared to Florida's statewide average of $11,759 and the national average of $2,377. Adding an ADU increases property value and dwelling coverage requirements, proportionally raising premiums.

HVHZ-compliant construction demonstrates reduced risk to insurers, potentially qualifying for premium discounts and ensuring claims coverage during hurricane events.

Steel Core vs. Wood Frame in Hurricane Zones

Traditional wood-frame construction requires extensive hurricane strapping, impact-resistant sheathing, and reinforced connections to meet HVHZ standards. The Mesocore modular steel core is robotically welded for precise structural integrity, achieving high wind ratings without field-applied reinforcement.

Factory welding eliminates the variability of on-site carpentry and ensures consistent compliance with Miami-Dade's stringent requirements. The steel core remains as part of the permanent structure, providing exceptional strength while serving as the delivery container.

Site Preparation and Foundation Costs for Miami-Dade ADUs

South Florida's unique geology and climate create site preparation challenges that significantly impact total project costs.

Concrete Pier Foundation vs. Slab-on-Grade

The Mesocore Model E ADU uses a concrete pier foundation with 8 piers, adapting well to variable soil conditions including high water tables and coral rock substrates common in Miami-Dade.

Pier foundations cost $4,000-$8,000 for materials and installation, compared to slab-on-grade foundations at $3,000-$7,000 for standard sites. However, piers avoid extensive excavation in challenging soil conditions, potentially reducing total site work costs.

Typical Site Prep Costs in Coral Gables, Kendall, and Homestead

Coral Gables (coral rock and limestone):

• Soil testing: $500-$1,500

• Rock removal or drilling: $3,000-$8,000

• Grading and fill: $2,000-$5,000

• Total: $5,500-$14,500

Kendall (variable soil conditions):

• Soil testing: $500-$1,000

• Tree removal: $1,000-$3,000

• Standard grading: $1,500-$3,000

• Total: $3,000-$7,000

Homestead (flood zone considerations):

• Soil testing: $500-$1,000

• Elevation requirements: $5,000-$15,000

• Grading and drainage: $2,000-$5,000

• Total: $7,500-$21,000

Properties in flood zones may require elevated construction adding $20,000-$50,000 to foundation costs, depending on required height and structural complexity.

Off-Grid Solar ADU Systems: Cost Savings and Incentives

The Mesocore Model E ADU includes a 6-KW solar system with 14 PV panels and two 10 kWh lithium-ion battery storage systems as standard equipment. This integrated design qualifies for substantial federal and state incentives while providing energy independence.

Solar Incentives Available in Miami-Dade County

Federal Investment Tax Credit (ITC):

• 30% of total system costs through 2032

• No maximum limit

• $30,000 solar system generates $9,000 federal tax credit

Florida Property Tax Exemption:

• 100% exemption on added value from solar installations

• Effective through December 31, 2037

• Ongoing annual property tax savings

Florida Sales Tax Exemption:

• 6% sales tax exemption on solar equipment

• Applies automatically at purchase

• Approximately $1,800 savings on a $30,000 system

Combined incentives reduce a $30,000 solar system to approximately $19,200 net cost (36% savings) plus ongoing property tax exemptions.

How Battery Storage Works During Hurricane Outages

Miami-Dade experiences frequent power outages during hurricane season. The Mesocore ADU's two 10 kWh lithium-ion batteries provide 20 kWh total storage—sufficient to power essential systems for 2-4 days during grid outages.

Some Miami-Dade jurisdictions have approved Mesocore ADUs to operate independently from the main house with no utility hookup or separate meter required. This off-grid capability eliminates connection fees, meter costs, and ongoing utility expenses while maintaining full functionality.

Battery systems charge from solar during normal operation and automatically switch to backup mode during outages, maintaining refrigeration, lighting, air conditioning, and communication systems when the grid fails.

ADU Construction Timeline: From Permit to Move-In

Building timelines for ADUs range from 8-18 months for traditional construction, but factory-built modular units dramatically compress on-site work.

Typical Permit Approval Timeline in Miami-Dade

• Pre-application research: 1-2 weeks

• Design and engineering: 4-8 weeks

• Permit application submission: 1-2 weeks

• Initial plan review: 4-6 weeks

• Resubmittal and corrections: 2-4 weeks

• Final permit issuance: 1-2 weeks

• Total permitting: 13-25 weeks (3.25-6.25 months)

The Pre-Approved ADU Blueprint Program cuts design and approval time by 4-8 weeks by using pre-reviewed county designs.

How Prefab ADUs Reduce Construction Time

Traditional stick-built ADU construction requires 12-40 weeks on-site:

• Foundation: 2-4 weeks

• Framing and structural: 4-8 weeks

• MEP rough-in: 4-6 weeks

• Inspections between phases: 3-6 weeks

• Interior finishes: 6-10 weeks

• Final inspections: 1-2 weeks

The Mesocore Model E ADU completes on-site installation and finish work in as little as 10 days after permit approval and site preparation. Factory-installed, Intertek-certified MEP systems eliminate rough-in inspections in many jurisdictions, further accelerating the approval process.

Compressed Modular Timeline:

• Foundation piers installation: 3-5 days

• Core delivery and placement: 1 day

• Wall assembly and roof deployment: 2-3 days

• Window/door installation: 1 day

• Interior finishes: 2-3 days

• Final inspection: 1 day

• Total on-site work: 10-14 days

Best ADU Floor Plans for Miami-Dade Properties

According to Miami-Dade County regulations, detached ADUs are generally limited to 800 square feet of the main home area (whichever is less), requiring efficient layouts that maximize livable space within tight constraints.

Compact ADU Layouts for Smaller Lots

Properties with smaller lot sizes need compact ADU footprints that preserve required setbacks and separation distances. The Mesocore Model E 410 square foot layout with 1 bedroom and 1 bathroom fits comfortably on smaller lots while providing full independent living functionality.

The open-concept kitchen, dining, and living area maximizes perceived space, while the full bathroom with 3'x3' shower pan and bedroom with full-height closet provide complete privacy and storage.

Multi-Use ADU Design: Office, Guest Suite, or Rental

The Model E ADU serves multiple purposes:

• Home office: Private workspace separate from main house distractions

• Guest suite: Self-contained accommodation for visitors with full kitchen and bath

• In-law unit: Independent living for aging parents or adult children

• Rental property: Income-generating unit with complete amenities

• Pool house: Luxury amenity for properties with swimming pools

Flexible design allows homeowners to shift usage over time as family needs evolve, protecting investment value through changing life stages.

Working with General Contractors for ADU Projects in Miami-Dade

Licensed general contractors coordinate site work, foundation installation, and finish carpentry not included in the Mesocore factory price.

What to Ask ADU Contractors Before Hiring

• Are you licensed in Miami-Dade County?

• Have you completed ADU projects specifically?

• Do you have experience with modular construction installation?

• What is your timeline for foundation and site work?

• How do you handle HVHZ inspection requirements?

• Can you provide references from recent ADU clients?

• What warranty do you provide on your work?

Typical Contractor Costs for Miami-Dade ADU Build-Outs

General contractor labor for Mesocore ADU installation includes:

• Foundation pier installation: $3,000-$6,000

• Wall installation and insulation: $3,000-$6,000

• Window and door installation: $2,000-$4,000

• Flooring installation: $1,500-$3,000

• Interior painting: $1,500-$3,000

• Exterior painting and trim: $2,000-$4,000

• Deck/porch construction: $3,000-$8,000

• Utility connections: $3,000-$10,000

• Total contractor costs: $18,000-$44,000

Mesocore manages drawings and permitting while local general contractors handle site prep, foundation, and finish work using materials provided in the factory container. This division of labor optimizes efficiency—factory production for complex systems, local labor for site-specific finishing.

In many areas, Mesocore has authorized dealers who manage the complete build-out and permitting process. Where dealers don't exist, the in-house team can step in to manage permitting and complete on-site construction.

Conclusion

Miami-Dade County's 171,683 eligible properties (per NACo analysis of the county's ADU program) can now add ADUs under regulations designed to address the region's severe housing shortage. Construction costs of $80,000-$200,000+ generate $900-$2,200 monthly rental income with strong ROI potential despite HVHZ compliance requirements. Mesocore's Model E ADU addresses Miami-Dade's unique challenges with wind-resistant construction meeting site-specific ASCE 7 requirements, factory-installed Intertek-certified MEP systems that eliminate rough-in inspections, and integrated 6-KW solar with two 10 kWh batteries qualifying for 30% federal tax credits. Factory-built efficiency reduces on-site installation to 10 days after permits, while financing options through HFS Financial (7.99%+ fixed, no equity required) and Ocean Capital Lending (ADU-specific programs) make projects accessible for homeowners ready to invest in backyard housing solutions.

Frequently Asked Questions

Can I build an ADU on my Miami-Dade property?

Yes—Miami-Dade now allows ADUs on a large share of single-family lots, with a county program and pre-approved blueprints to streamline approvals. Detached units are generally capped at up to 800 sq ft or a percentage of the main home (whichever is less), and a renewable Certificate of Use is required for occupancy.

How much does a 400–500 sq ft ADU typically cost end-to-end?

Factory-built modular options (e.g., Mesocore Model E) commonly land around $155,000–$189,000 installed once you include delivery, foundation, utility tie-ins, and finish work. Traditional stick-built projects vary more widely (~$97,500–$176,000) before site surprises and HVHZ upgrades.

How long will permitting and construction take?

County permitting usually spans 6–18 months from pre-application to final inspections, faster if you use pre-approved plans. Once permitted and the site is prepped, modular ADUs can finish on-site in roughly 10–14 days, far quicker than traditional builds.

What hurricane (HVHZ) requirements apply?

ADUs must meet Miami-Dade’s HVHZ standards with site-specific ASCE 7 wind design (often 170–186 mph) and impact-rated openings with Miami-Dade NOA or Florida Product Approval. Modular steel-core systems with factory-installed, Intertek-certified MEPs help satisfy these requirements while reducing on-site inspections in many jurisdictions.

How do homeowners finance an ADU—and what ROI is typical?

Common routes include HELOCs (variable rates), cash-out refis (fixed rates), construction loans, and ADU-specific lenders; some programs offer fixed personal loans starting near 7.99% with no home equity. Rents often fall in the $900–$2,200/month range depending on size and location, with many projects penciling out to strong long-term ROI—especially when factoring in property value lift and potential solar savings.