Hurricane-Resistant Construction in South Florida

Hurricane-resistant construction

The short answer

The load path

A hurricane looks for the weakest link

Wind does two things to a house. It pushes on the walls and it lifts the roof, and when a window or door breaks, the wind gets inside and pushes the roof up from below as well. A house resists that only if the force has an unbroken path from the roof covering to the ground. The Florida code sets requirements for each link, and the structural engineer designs the connections for the wind speed and exposure of the lot.

The order matters in practice. On a new house every link is designed together. On an older house, the links are usually upgraded one at a time, and the roof and the openings are where the Florida code and the state grant program put the attention (see hardening an older home).

Design wind speeds

The wind speed your house is designed for

The Florida Building Code defines the High-Velocity Hurricane Zone (HVHZ) in one line: “This zone consists of Broward and Miami-Dade counties” (FBC-Residential R202). Houses there are designed to the HVHZ wind loads of section 1620.2, which uses the ASCE 7 standard. Palm Beach County sets its speeds with its own wind-speed map, which steps up from the lake side to the coast.

Ten or twenty miles an hour sounds like a small difference. It is not, because wind pressure on a building grows with the square of the wind speed. Our arithmetic from that relationship:

So a house designed for 175 mph in Miami-Dade carries about 36% more wind pressure than one designed for 150 mph in western Palm Beach County. That is why the same window, door or roof system can be approved for one lot and not another.

Windows, doors, skylights

Openings: impact-rated or protected

In the HVHZ, section 1626.1 of the building code requires that exterior walls, the roof, outside doors, skylights, glazing and glass block “meet impact test criteria or be protected with an external protection device that meets the impact test criteria.” Either impact-rated products or approved shutters satisfy it. The tests are specific:

Sources: FBC-Building 1626.2, 1626.3, FBC-Residential R301.2.1.2.

In Palm Beach County, the house is outside the HVHZ but inside what the code calls the wind-borne debris region. According to the Florida Building Commission, areas with design wind speeds “above 140 mph in hurricane prone regions are designated WBDR regardless of adjacent exposure conditions.” Every zone on the Palm Beach map is 150 mph or more, so there too, “exterior glazed openings … shall be protected from windborne debris” (R301.2.1.2), tested to the ASTM E1996/E1886 large-missile standard or the TAS protocols. The residential code also allows one low-tech option there: for a house with a mean roof height of 33 ft or less, precut wood structural panels at least 7/16 in. thick, with the attachment hardware permanently installed, may serve as the protection. (Houses in the HVHZ follow the HVHZ provisions instead; R301.1.)

Approved products. Windows, doors, shutters and roofing are “product approval” products under section 553.842, Florida Statutes. Each one carries a Florida Product Approval number or a Miami-Dade Notice of Acceptance (NOA search), and in the HVHZ the approval must cover HVHZ use. The approval also sets the design pressure the product is rated for, which has to meet the pressure the engineer calculates for that opening. Our NOA and product compliance page explains how the approvals are matched to the plans.

Replacing windows in an existing house is covered by the Existing Building code (707.4): replacements meet today’s wind and impact rules. In the HVHZ there is one narrow exception for one- and two-family homes built under codes before September 1, 1994, when no more than 25% of the glazed area is replaced within 12 months. See our hurricane-rated window systems.

Roof system

The roof: covering, underlayment, deck and straps

Most wind damage starts at the roof, so the code treats it as a system of layers:

1. 1Roof deckIn the HVHZ: plywood at least 19/32 in. thick, nailed with 8d ring-shank nails no more than 6 in. apart at the panel edges and intermediate supports (FBC-B 2322.2.3 to 2322.2.5).
2. 2UnderlaymentThe residential code offers three methods: a self-adhering membrane over the whole deck, a self-adhering strip at least 3¾ in. wide over the sheathing joints, or two layers of underlayment. Metal caps on the fasteners are required at 170 mph and above (R905.1.1.1). In the HVHZ, roof assemblies follow the code’s HVHZ roofing chapter.
3. 3Roof coveringTile, shingle or metal, each installed to its product approval for the design wind speed.
4. 4Roof-to-wallRated connectors tie each truss or rafter down to the wall; on a block house, into the concrete tie beam.

Sources: FBC-Building 2322, FBC-Residential R905.1.1.1.

Re-roofing in the HVHZ. Not more than 25% of a roof may be repaired, replaced or recovered in any 12 months unless the whole roof section is brought to code (FBC-B 1521.4), except that a roof already built to the 2007 code or later needs only the repaired part at current code (section 553.844). Deteriorated sheathing must be replaced (1521.5), and no new covering may go over existing tile or metal (1521.16). The roofing contractor must tell the owner that the existing deck “may have to be renailed” (1524.1).

Structure

Walls and foundation: where the load ends

In the HVHZ, buildings “shall be designed and constructed to meet the requirements of Chapters 26 through 31 of ASCE 7” (FBC-B 1620.1). On a new concrete-block house, that design is the engineer’s: the reinforced cells and tie beam that receive the roof connectors, the connections at the floor and foundation, and the sizing of every lintel over a wide opening. Large glazed walls, like the one below, are engineered openings with approved products and rated anchors.

Storm surge and flooding are a separate set of rules: the lowest floor elevation in a flood zone (FBC-R R322) and, for work on an existing house, the substantial-improvement test. Our FEMA 50% rule guide and build-cost guide cover both.

Existing houses

Hardening an older home

The first Florida Building Code “was adopted in 2001 and implemented on March 1, 2002” (ICC), after Hurricane Andrew in 1992. Many South Florida houses are older than that. The code does not make an owner upgrade a sound house on its own, but a re-roof triggers upgrades under the Existing Building code (section 706):

The wind mitigation form. Insurers must include “actuarially reasonable discounts, credits, or other rate differentials” for construction that reduces windstorm loss, such as roof-to-wall strength and opening protection (section 627.0629). The evidence is the state’s Uniform Mitigation Verification Inspection Form, OIR-B1-1802, now in its April 2026 revision (rule 69O-170.0155). Insurers must accept it when it is signed by a licensed home inspector, a certified building code inspector, a licensed general, building or residential contractor, an engineer or an architect (section 627.711). The discount itself is up to the insurer. Our roof inspection and wind mitigation page explains the report.

My Safe Florida Home. The state grant program (section 215.5586) pays $2 for every $1 from the owner, up to $10,000, or up to $10,000 with no match for low-income applicants. The house must be a homestead, insured for $700,000 or less, built before January 1, 2008, and inspected by the program within the previous 24 months. Eligible work is opening protection (exterior doors, garage doors, windows, skylights), roof-to-wall connections, roof-deck attachment, and secondary water resistance with a new roof covering, done by licensed contractors. Funding depends on the Legislature each year; in August 2026 the program said it was accepting applications.

Interactive checklist

Before you build, re-roof or replace windows: a checklist

Our process

How we build and upgrade for hurricanes

On new homes, the engineer’s wind design, the product approvals and the inspections are planned together before the permit is filed, so each opening and connection is specified once and checked on site. On existing houses we usually start from the openings and the roof: impact window installation, impact doors, garage door replacement and roof replacement, with the deck, water barrier and roof-to-wall work the code triggers.

For an example of a new house built with engineered glazing, see our modern new-construction home project. Tell us about the house and what you want to upgrade, and we will walk you through the wind speed, the approvals and the permit path for it.