Plywood Shuttering: How resourceful is it as protection during hurricanes?
When the debris flying around in a hurricane punctures your home the trouble begins.
The larger the opening, the better the chance for building failure. Stop punctures, save homes.
For those without hurricane resistant doors and winds, shuttering is the first line of defense. The least expensive option will be do-it-yourself plywood shuttering. But how good is that?
The answer is surprisingly complicated. When wind invades your home, the pressure inside rises and presses against the wall and roof. At the same time wind funnels over your house act like wind over an airplane wing trying to lift off. If those forces win, you lose your home.
The building code in Florida is designed to beat back those forces. The code is strongest in South Florida, where it is assumed by officials that hurricanes will be strongest and relax as you move north into the panhandle. In the Miami-Dade area, plywood shutters won’t even meet code but under our local law they are permitted.
Testing shows an opening as small as one broken window can quickly escalate into catastrophic damage.
Plywood shutters can be punctured by airborne objects but the Florida building commission believes the puncture will be too small to do catastrophic damage in our anticipated wind speeds. But to meet those expectations correct installation is critical and there are important restrictions.
First, the plywood you use should be at least one-half inch thick. Thicker wood buys more protection. More on that at the end of this story.
Second, there are shutter size restrictions. In general, the maximum opening you can cover is 40 inches by 8 foot. Larger openings like big glass sliding doors, large windows and garage doors will present challenges in securing the wood. One member of the Building commission told me that a frame around large openings could be engineered and the wood attached to that, but that would take time in the hours before a storm. Large openings are most effectively handled by commercial products.
Third, the method of attachment is of upmost importance. The rows of attaching hardware differ from masonry to wood. Even the size of the washers is important.
The building department is ready to help you with details and you can find those instructions here.
Studies show just closing all the doors to every room inside the home can significantly improve the odds of keeping your roof if some shutters fail.
Now obviously, when your in an emergency situation no one is checking for code violations on your temporary shutters. However, there is good science behind the code and improperly installed shutters may not give the protection you expect and might give false sense of security and add to the flying debris. Oh, and don’t expect to get the storm shutter reduction in insurance rates wood panels.
The gold standard for hurricane protection remains Miami-Dade approved commercial products. However, tests show that double thicknesses of ½ inch plywood can approach that effectiveness and still be light enough to lift and move around. The combination of plywood shutters and commercial products can go a long way in protecting your home.
Also, add to your shutter effectiveness by getting your home a wind mitigation inspection to point structural vulnerabilities. There may be some quick and cheap fast fixes that can do to shore up your home.
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