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 if it is a ravenous beast and takes your entire roof.
Recent intense storms in the gulf region have 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 more 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 how homeowners can make some simple repairs and improvements to their homes, which will increase their durability in severe storms. Some of these are simple and straightforward, others are much more involved and may require the help of 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 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 damage of the roof covering led to severe water damage both during and after Hurricane Andrew. Damage surveys conducted following the hurricanes of 2004 and 2005 have also highlighted the frequency of roof cover damage. Of the homes that had enough damage to file an insurance claim, 95 percent had some level of roof covering damage. Studies have also highlighted the fact that damage to the roof covering during a hurricane can lead to substantial water damage in subsequent rainstorms. Both the initial water intrusion and the later leakage can lead to significant mold problems.
One way a shingle roof fails is by allowing the wind to lift the shingle and then allow it to get torn off. When shingles are installed, the manner in which 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 and are the least effective in keeping shingles in place. Another critical factor is layers of roofing. The high wind rating that many roofs have is dependent on it being the only layer of roofing. Shingles installed over old shingles 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 to 4 weeks ahead of the storm, as the roofing adhesive needs this time interval to properly cure and be effective. A homeowner can perform these repairs, or you may have a roofing contractor perform these tasks. You'll need a ladder, a putty knife and a caulkign gun. Apply the adhesive to the undersude 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, its better to get professionals for this job. This job is not that 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 are more prone to damage, from the storm’s wind, or by a well-intentioned owner trying to make repairs. If you find that your shingles break when attempting to seat 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 that they build to 130 mph wind ratings per the local codes. He also said, “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," said Simpson. "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. Its 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 warned.
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 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 toe hold for the storm’s fury. Metal sheeting, metal tiles and other roof top items like vents, covers, and chimneys need to be maintained as well. Loose chimney and other flashing can allow water to penetrate the home and can cause mold, weaken drywall and cause it to fail as well.
Chip Ezzo of Chip’s Roofing, in Berthoud, CO, spent the first 12 years of his 20 plus 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 said “Both metal roofs and shingle roofs can withstand severe storms if they are 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 lie 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 failures of roofs 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. These codes are 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 is called the Bernoulli effect and 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 homes interior. Often the loss of the ceiling joists or trusses will cause a cascade failure of the walls as well. Another problem that occurs with the loss of the roofs sheathing is that it 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 can improve the home’s strength, and reduce potential storm damage, they may fall short of current local building codes.
While severe storms may be exciting to watch on the Weather Channel, living though 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.
Learn all about hurricane-proofing your house from our friends at AOL's DIY Life.