What Is the High Velocity Hurricane Zone?
The High Velocity Hurricane Zone (HVHZ) is a geographic designation under the Florida Building Code (FBC) that applies to Miami-Dade and Broward counties. It reflects the extreme wind exposure these counties face—a 185 mph design wind speed—and triggers the most stringent building requirements in Florida.
The HVHZ designation was created after Hurricane Andrew (1992) devastated South Florida, revealing catastrophic failures in building materials and installation practices. The resulting code revisions—the most aggressive building code changes in U.S. history at the time—introduced the NOA (Notice of Acceptance) approval system still in use today.
For homeowners in Miami-Dade or Broward, this means every roofing product installed on your home must have a valid Miami-Dade NOA, and the installation must comply exactly with the NOA's specifications. Non-compliant installations can result in failed inspections, permit revocations, and insurance claim denials.
HVHZ Counties at a Glance
Miami-Dade County
HVHZBroward County
HVHZUnderstanding NOA Product Approval
Miami-Dade Notice of Acceptance (NOA)
Every roofing product installed in Miami-Dade must hold a valid NOA issued by the Miami-Dade County Product Control Division. NOA covers the product's performance under Florida Product Approval Protocol TAS 100, 105, 107, 110, 125, and 126.
Florida Product Approval (FL#)
Products with an FL# approval from the Florida Building Commission are approved statewide. In Broward, FL# products are generally accepted. In Miami-Dade, a specific Miami-Dade NOA is typically required (FL# alone is insufficient for most applications).
Test Protocols (TAS)
TAS (Test Application Standards) are Florida's unique testing protocols for hurricane zone products. TAS 107 covers wind tunnel testing for uplift resistance. TAS 117 covers fire testing. No other state has protocols as stringent as Florida's TAS standards.
Installation Specification Compliance
The NOA does not just approve the product—it specifies exact installation methods, fastener patterns, deck thicknesses, and underlayment requirements. Any deviation from the NOA installation specification voids the product approval.
Material Compliance in HVHZ
Must have Miami-Dade NOA. Standard shingles are not HVHZ compliant. Rated to 130+ mph per NOA. Examples: GAF Timberline HDZ (NOA 23-0529.04), Owens Corning Duration (NOA 12-0603.09).
Most tile products have strong NOA track records. Foam adhesive systems are standard in HVHZ. Must verify both the tile AND the adhesive system have independent NOA approval.
Standing seam systems from major manufacturers (Englert, Metal Sales, ATAS) hold HVHZ NOA approvals. Concealed clip systems rated to 175+ mph. Verify specific profile NOA.
Commercial flat roofing systems must be FM Global approved with minimum FM 1-90 or as required by the specific uplift calculation for the building. Fully adhered preferred over mechanically attached.
HVHZ Installation Requirements
- Secondary Water Barrier (SWB): self-adhering modified bitumen underlayment over entire deck before primary roofing material
- 6d ring-shank nails at 6" o.c. field, 6" o.c. at edges for deck attachment (minimum; NOA may require more)
- Hurricane straps or clips at every rafter/truss-to-wall-plate connection
- Closed-cut valley flashing with minimum 4" coverage
- Pipe boot flashings sealed with compatible caulk and metal collar—no fabric patches
- Ridge caps must use NOA-approved products and installation method
- All penetrations sealed per NOA specification
- Building permit required for all roofing work in HVHZ—no exceptions