Based on data collected by various sources in Florida, where preparation for hurricanes is far more sophisticated and thorough than in the Caribbean, the house roof been proven to be one of he most vulnerable areas to strong winds.
Once the roof is blown away or damaged, the entire structure of the house is susceptible to major damage, exposing the contents and occupants to harm.
In Barbados the roofs of our homes are primarily of two types, corrugated metal sheets and shingles. How much do you know about the strength of your roof, based on its type, age and other factors? How do you, even at this early stage of the 2012 hurricane season check on its vulnerability and perhaps take steps to reinforce it?
Today, we offer some tips that might assist you if your home contains shingles. It is based on research done in Florida, and you may therefore have to tailor its application to suit your peculiar circumstances.
Sooner or later, all roofing needs to be replaced. If shingles are old and worn, patching or limited repairs won’t help when a hurricane strikes. If you know how long it has been since your shingles were replaced, that is a good starting point.
While many of the better products come with limited warranties for 25, 30 years or more, the hot sunny climate conspires to shorten that life span. Ultraviolet rays break down the asphalt used to bind the stone granules to the top surface and heat bakes the shingles causing the components to break down and the shingles to become brittle and lose strength. The standard three-tab shingles used in the past were typically rated for only 15 years.
Failure Rate during 120 MPH Winds by Age of Roof
Studies of hurricane damage have shown that when wind gusts exceed about 120 mph, between three and five out of 10 shingle roofs suffered enough damage to require re-roofing, regardless of the age of the roof. As shingle roofs get to be more than about 10 years old, the failure rates in areas that likely experienced only 75 to 95 mph gusts ran at a rate of one to two out of 10, while the failure rates dropped to about one in 20 or less for roofs that were less than five years old.
Failure Rate during 95 MPH Winds by Age of Roof
Consequently, if your roof is more than 10 years old and particularly if it shows some of the signs of aging, you are likely to suffer significant shingle damage if a strong hurricane strikes your community.
From your roof
Look for cracks, broken tabs, buckling curling or blistering of the tabs, and tabs with most of the surface granules worn off. These signs of aging are very strong indicators that you are likely to lose shingles during a hurricane.
If your shingles are in good shape, they should lie flat and the lower edges should be well adhered to the top surface of the shingle below. Shingles should be inspected at least yearly for signs of aging and weakness.
If your shingles are cracked, have broken tabs, you can see shiny white fiberglass fabric (weave), the tabs are bowed or cupped, or granules are worn off, then your shingles are in need of replacement because they will probably not stay on the roof in high winds.
Carefully lift up on a number of tabs:
Using your thumbs or fingers, pressed against the bottom edge of the shingle tab and slowly but firmly lift up on the edge of the shingle to test how well it is attached to the top of the shingle below.
Next week we will look at roofs that are covered by metal sheets.