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Miami — Tier-1 Pillar

Miami Accessory Dwelling Unit — Miami-Dade RU-1 vs Miami Beach Prohibition

Miami ADU reality. Unincorporated Miami-Dade allows ADUs in RU-1 and AU; Miami Beach and most Coral Gables prohibit. Chapter 33 compliance, septic/sewer capacity, FEMA elevation if in flood zone. $120K-$300K typical.

~1 min read·Updated 2026-04-23

Miami ADU rules fracture by jurisdiction. Unincorporated Miami-Dade County (under Chapter 33) permits ADUs in RU-1, AU, and a handful of other residential zones with size caps (typically 800 sqft or 50% of primary structure, whichever is less) and septic/sewer capacity verification. City of Miami permits detached accessory structures under Miami 21 zoning code but with tight restrictions. Miami Beach Land Development Regulations Sec. 142-905 prohibits ADUs outright in most single-family zones — the city's historic-preservation posture rejects density additions. Coral Gables permits in some zones but with Board of Architects review on design.

AskBaily routes Miami ADU projects to one Florida CILB-licensed contractor who knows the exact zoning code governing your parcel — Miami-Dade Chapter 33, Miami 21, Miami Beach LDR, Coral Gables Zoning, or one of 30+ city-within-county codes.

Frequently asked questions

Can I build an ADU in Miami Beach? Usually not — Miami Beach LDR Sec. 142-905 prohibits most accessory dwelling units in single-family residential zones.

Can I build an ADU in unincorporated Miami-Dade? Yes in RU-1, AU, and certain other residential zones under Chapter 33, subject to size caps and septic/sewer verification. Confirm zoning at miamidade.gov before scoping.

How much does a Miami ADU cost? New-build detached 600-800 sqft: $180K-$350K. Garage conversion: $120K-$220K. Luxury Coral Gables guest house: $400K-$900K.

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Who is Baily?

Baily is named after Francis Baily — an English stockbroker who retired at 51, became an astronomer, and in 1836 described something on the edge of a solar eclipse that nobody had properly articulated before: a string of bright beads of sunlight breaking through the valleys along the moon’s rim.

He wasn’t the first to see them. Edmond Halley saw them in 1715 and barely noticed. Baily’s contribution was clarity — describing exactly what was happening, in plain language, so vividly that the whole field of astronomy paid attention. The phenomenon is still called Baily’s beads.

That’s what we wanted our AI to do. Every inbound call and text has signal in it — a homeowner’s real question, a timeline, a budget, a hesitation that means “yes but.” Baily listens to every one, 24/7, and finds the beads of light.

Baily was a businessman before he was a scientist. That’s our vibe too.

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