Storm-Proof Your Roof
When storm season approaches, one of the key components to keeping you and your family warm and dry is your roof. Tropical storms and hurricanes are well known as “roof eaters,” whether the storm is having a light snack and nibbles a few of your shingles, or it is a ravenous beast and takes your entire roof. As you might have expected, the cost for a house roof replacement caused by a storm is exorbitant so preparing for it before is essential.
Intense storms in the Gulf region opened many people’s eyes to the perils of Mother Nature combined with poor or old building standards. Florida’s building codes are some of the most rigorous in the country. These new codes are the refinement of years of improvements in building technologies, and are intended to make homes safer in areas of extreme weather.
The Florida Division of Emergency Management has put together a series of tutorials on simple repairs and improvements homeowners can make to their houses, for increased durability in severe storms. Some of these are simple and straightforward, others are much more involved and may require the help of local roofing contractors.
First Line of Defense
Many homes have asphalt shingles as their roof covering. These may be new architectural shingles with wind ratings up to 150 mph, or they may be older three-tab style with wind ratings of 50 to 60 mph.
In Hurricane Andrew, a study by the National Association of Home Builders Research Center showed that widespread damage to roofs seriously affected 77 percent of the homes surveyed. This led to severe water damage, both during and after the hurricane. Damage surveys conducted following the 2004 and 2005 hurricanes also highlighted the frequency of roof cover damage. Of the homeowners who filed an insurance claim, 95 percent had some level of damage to their roof covering. Studies have also highlighted the fact that existing roof problems present roof damage covering during a hurricane can result in substantial water damage in subsequent rainstorms. Both the initial water intrusion and the later leakage may lead to significant mold problems.
One way a shingle roof fails is by allowing the wind to lift the shingle and then tear it off. When shingles are installed, the way they are fastened will provide various degrees of wind resistance. Shingles that are 6 nailed are far more robust than those that are 4 nailed. Staples were widely used years ago but are the least effective in keeping shingles in place. Another critical factor is layers of roofing. The high wind rating that a roof may have is dependent on it being the only layer of roofing. New shingles installed on top of old have significantly lower wind ratings. As shingles age, they become more brittle, and often the adhesive that holds the leading edge down will fail.
The simple task of applying roof adhesive to loose shingles can greatly reduce the chances of your shingles getting ripped off under high wind conditions. A short term fix is the hand tabbing of shingles: The Florida Division of Emergency Management recommends that repairs be made 2-4 weeks ahead of a predicted storm, as the roofing adhesive needs this time interval to properly cure and be effective. You can do the work yourself or hire a roofing contractor.
If you decide to take on the DIY roofing project yourself, you'll need a ladder, putty knife and caulking gun. Apply the adhesive to the underside of the shingle if the shingles are still somewhat flexible. Pressing the shingle down firmly with your foot is an easy way to ensure full contact with the adhesive.
If your roof is steep, or you are uncomfortable with heights, it's better to get professionals for this job. The work is not super technical, but it can be a big project. Many homes may have a few thousand square feet of roof and the inspection and repair could take some time. As shingles age, they become more brittle and prone to damage, from either the storm’s wind or a well-intentioned owner trying to make repairs. If you find that your shingles break when you attempt to seal the edges, it may be time for a new roof.
Coastal areas are prone to higher winds than most inland areas. This is clearly demonstrated in the IRC’s (International Residence Code) wind maps. Outlying areas may see winds of near 150 mph. The marine environment also adds some challenges to building. Rex Simpson, from Gallop Roofing and Remodeling in Elizabeth City, NC. says they build to 130 mph wind ratings per the local codes. He adds, “We have special concerns because of our proximity to the ocean, we use aluminum and stainless steel flashing, along with hot dipped nails. Regular nails and galvanized flashing just don’t hold up.
“We do not recommend that homeowners perform work on their own roofs. Safety is a big issue, and most homeowners do not have the experience. Gallop roofing has been serving the Outer Banks of North Carolina for over 50 years, and we have seen our share of storms. It's not just the shingles, the chimney and other trim needs to be inspected too. Loose flashing can lead to greater damage, to the roof, or even the siding,” he warns.
Periodic inspections are your best methods to ensure that your roof will perform as intended. Inspections in the attic may allow you to spot trouble before it becomes a major problem. Look for discoloration or signs of water intrusion. Safety is a concern in attics as well. It is not uncommon to hear of damage to ceilings from a misplaced step, or of bumped heads in these confined spaces.
Failure with New Roofs
Where I live in Colorado, hurricanes are never an issue, but we still get extremely high winds. One common roofing failure in my climate with new asphalt shingle roofs has to do with the roof installation. The adhesive layer that binds one course to the next is “activated” by some exposure to warm sunny days. Roofs that are installed in early spring or fall may not see the temperatures needed to allow the adhesive to properly bind. I have seen neighbors' homes lose a great number of shingles due to this problem. Even the repairs were torn off by wind a number of times before the condition was stabilized.
Other Roofing Materials and Problems
If you have a metal or tile roof you can also run into problems. Loose tiles are often dangerous projectiles when propelled by hurricane force winds. These can then cause more damage to your roof. Many homes have porches that have been added on over the years. By their nature, these are often not as robust as the rest of the home and can provide a toehold for the storm’s fury. Metal sheeting, metal tiles and other rooftop items like vents, covers, and chimneys need to be maintained as well. Loose chimney and other flashing can allow water to penetrate the home, leading to mold, and weaken drywall, causing it to fail as well.
Chip Ezzo of Chip’s Roofing, in Berthoud, CO, spent his first 12 years in the roofing trade working in storm-prone areas of Florida. His basic advice to homeowners is to have their roofs inspected regularly. He also claims, “Both metal roofs and shingle roofs can withstand severe storms if they're properly installed and well maintained. Standing seam metal roofs hold up a bit better than Pro-Panels because the screws are protected. I have seen damage range from missing shingles and panels to the complete loss of plywood sheathing, it just depends on the storm and how well your roof is built. Here in Colorado, we build to high wind standards, just like many areas in Florida. One big difference to various levels of a roof’s performance lies in the level of experience of the installer, and how roofs are inspected during construction. We had four required inspections during the builds in Florida, while here in Colorado a lot of areas only require one final inspection. Less skilled or reputable builders may cut corners that inspectors can’t see. This can lead to problems down the road.”
So far we have talked about roof coverings, but serious roofing failures often have little to do with what is on top, but rather how all of it is put together. Modern codes in severe storm areas require the use of tie-downs and straps or brackets that hold the rafters to the walls and the walls to the foundations, much like seismic codes for earthquake prone areas. When storms are severe, hurricane force winds can reduce the pressure above a roof, lifting the roof. This Bernoulli effect has turned many homes into open-air structures. If your home is old, the rafters may be simply toe-nailed to the wall’s top plates. This simple building method does not provide much resistance to uplift that keeps a roof on during severe conditions.
Most catastrophic failures in intense storms are due to some variation of losing the roof sheathing, with or without the rafters attached. The gable ends of homes are especially vulnerable. Once this layer is gone, water from wind-driven rain can completely destroy the home's interior. Often the loss of the ceiling joists or trusses will cause a cascade failure of the walls as well. Another problem is that loss of the roof's sheathing allows the wind to get a better grip on the home and can cause walls and other areas of roofing to “blow out.” If you are re-roofing, it is a good ideal to add additional fasteners to the decking prior to installing the roof covering. Tie straps and additional structural elements can often be added in attic spaces as well. While these measures may improve the home’s strength, and reduce potential storm damage, they might fall short of current local building codes.
While severe storms may be exciting to watch on the Weather Channel, living through them or rebuilding after one is a completely different matter. Proper maintenance, inspections, and adherence to current building codes and standards will increase the chance that your home is not damaged by a storm.
Updated May 6, 2018.
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