Garage doors and the hurricane code

What we found

The way a garage door failure damages a house is well understood by engineers, and little known by homeowners. A garage door is usually the largest opening in a house, and the least braced.

IBHS describes the sequence. Wind pushes the door in. Pressure builds inside. Then the roof and walls take force from both sides at once.

The rule that deals with this is younger than most of the homes it applies to. Wind-borne debris rules first entered ASCE 7, the national wind-load standard, in 1995, at a 110 mph trigger. Florida had no statewide building code until 2002.

We computed the housing-age side ourselves. From Census ACS 2023 five-year table B25034, 76.3 percent of US housing units were built in 1999 or earlier and 89.9 percent in 2009 or earlier.

Read that as the most homes that could be exposed, not a count of unprotected doors. To see what your own door needs, try our wind-rating checker.

Why is a garage door a structural part of the house?

Because when it fails in high wind, the damage spreads to the whole house. Most people think of the garage door as a convenience.

It opens, it closes, it makes noise, and the choices are about insulation and looks. That holds until a major windstorm.

Then the door turns out to have had a structural job nobody gave it.

IBHS states the mechanism directly: “High winds can push a garage door inward, allowing pressure to build inside your home, pushing up on the roof and out on the surrounding walls—often resulting in more significant structural damage.”

Engineers call this internal pressurization. A sealed building makes wind flow around it. A breached one lets the wind in. Inside, it pushes up on the roof deck and out on the walls, while wind outside is pulling on the same surfaces. The two forces add.

IBHS also reports that in field damage investigations after storms, “90% of homes whose garage door survived the storm had no structural damage to the roof.”

HyreGarage analysis: that is a pattern seen in field surveys, not a controlled test. Homes whose doors survived also differ in other ways: they are often newer, better built and less exposed.

We quote it because IBHS published it, and because it points the same way as a well-established mechanism. One percentage does not settle cause and effect.

Two key numbers in the rule were never based on research

The University of Florida report includes a history of the rule, drawn from talks with the people who wrote it, including a past chair of the ASCE 7 Wind Loads Subcommittee. It shows that two of the numbers everyone quotes did not come from research.

In ASCE 7-98 the trigger rose to 120 mph, except within one mile of the coast, where 110 mph still applied. The report is blunt about why.

“This reduction in the WBDRs was driven primarily by resistance from building officials and authorities having jurisdictions to adopt the previous designation, and not on new research or observations.”

And on the one-mile distance: “The Committee’s criteria for using the one-mile distance was based largely on anecdotal evidence from damage assessments; no specific research had been conducted to inform the selection of this specific distance.”

The 2022 edition finally dropped the word “coastal”. It uses Exposure D instead: flat land or water upwind for at least 5,000 feet.

The report explains that this condition “is likely to occur regardless of whether the large body of water (at least 5,000 ft of fetch) is coastal or inland (i.e. ‘the wind can’t tell the difference’).”

The report adds that the committee came to think the word was included “in error and an artifact of the damage assessments after Hurricanes Andrew and Hugo that drove the initial adoption”. Those assessments went to the worst damage first, which was on the coast.

The effect in Florida is current. Under the 2023 code, the report says, “inland regions in central Florida and the panhandle adjacent to large lakes or inland bays with design wind speeds between 130 and 140 mph will now also require buildings to have opening protections.”

The same paragraph notes that “[t]here are stakeholders within Florida that are interested in reverting the 9th Ed. FBC(R) to the WBDR definition in the 7th Ed.”, meaning back to ASCE 7-16. This is live, disputed and may change. Check the currently adopted edition rather than relying on this page.

What we could not find, and so did not write

Three gaps shaped this page.

ASCE 7 itself. The standard is sold commercially and we did not buy it. Every ASCE 7 definition here is quoted from the University of Florida report for the Florida Building Commission. That is a reliable primary document of the Commission, but still a go-between, and we name it every time.

The IBHS FORTIFIED technical documents. The FORTIFIED Home standard and its garage door bulletins are published, but the IBHS research library page we tried was members-only. So we quote only IBHS’s public news release.

We publish no FORTIFIED requirement, design pressure table or pass criterion from that program. If you want a FORTIFIED designation, work from the current standard itself.

Effective dates outside Florida. The code history is Florida’s because Florida has one statewide code with a documented history. Texas, the Carolinas, Georgia, Alabama, Mississippi and Louisiana adopt model codes on their own schedules, sometimes with local changes, sometimes county by county.

Compiling those dates is real work, and we have not done it. So the housing-age table covers those states, but the code side does not. We have not put a national date on a Florida timeline.

One more thing we chose not to do. We could have multiplied the pre-code housing share by a guessed garage rate and published “X million unprotected garage doors”.

That number would spread widely and would not be true. It would stack a ceiling on top of a guess about replacement rates we have no evidence for. The data supports a range, so we published a range.