The Florida Building Code's High-Velocity Hurricane Zone (HVHZ) provisions, which cover all of Miami-Dade County. As of October 2026, an ADU here needs structural design for HVHZ wind loads, and windows, doors and roofing with Miami-Dade product approval, or approved shutters.
What is the High-Velocity Hurricane Zone?
It is the part of the Florida Building Code that applies only to Miami-Dade and Broward counties. It sets stricter wind design, testing and product approval rules than the rest of the state. Every ADU in our service area falls under it.
Which code edition is in force?
The 8th Edition (2023) of the Florida Building Code, which adopted the ASCE 7-22 wind standard, applies as of October 2026. The 9th Edition (2026) is expected to take effect on or around December 31, 2026. Which edition governs depends on when your permit application is filed.
What does HVHZ mean for an ADU in practice?
- Openings. Windows, doors and garage doors need a Miami-Dade Notice of Acceptance (NOA), or must be protected by approved shutters.
- Roof. Roof covering, underlayment and fastening must follow HVHZ rules and approved products.
- Structure. Continuous load paths, from roof to foundation, designed for the site's wind exposure.
- Inspections. Extra inspections for items such as roof sheathing nailing and tie-downs.
Does it apply to a garage conversion or an existing efficiency?
The new and altered parts must meet current code. Closing in a garage door opening, adding windows or replacing a roof all bring HVHZ requirements into play. Older openings that stay may also need protection, depending on the scope.
Is a factory-built ADU an option?
Only one approved for use in the HVHZ. A modular unit must carry Florida approval for Miami-Dade wind requirements. Many products sold elsewhere do not.
When does the wind code cost the most?
It depends on exposure and openings. A unit near open water or with large glass doors needs heavier-rated products. Fewer, smaller openings and a simple hip roof usually cost less to make compliant. We design with that in mind.
Related
Sources, as of October 2026: Florida Building Code, 8th Edition (2023), High-Velocity Hurricane Zone provisions; PermitPlace, "Florida's 2026 Building Code: What's Changing?"; Miami-Dade product control (Notice of Acceptance).
Updated October 2026