Wind Damage and Your Roof

    

Shingle blow off When your roof sustains wind damage, expert analysis is vital. Only an experienced, certified roof inspector is qualified to distinguish the damaged parts of your roof from those that remain intact. You don't want to pay for unnecessary repairs, but you also don't want damaged areas to escape detection.

Types of Roof Damage

Homeowners living in Maryland, Washington D.C. and Virginia face the possibility of both acute and incremental roof damage. Acute damage occurs when high winds cause falling branches or when there is direct damage to the shingles themselves. Incremental damage occurs as windstorms gradually weaken the bonds between shingles over a period of years. Aging shingles may be more vulnerable to wind damage as they get brittle, curl or lose mass. These weakened shingles are more prone to wind uplift that may break them or tear them loose from the roof.

Acute roof damage

If variety is indeed the spice of life, then DMV weather makes life spicy indeed. In this part of the country, we enjoy long periods of beautiful weather with light winds and lots of sun. Unfortunately, we are also perfectly situated to sustain assaults by everything from tropical storms to blizzards. Severe thunderstorms and even tornadoes also bring high winds to the Mid-Atlantic. Observers at National Airport once recorded a wind gust of 98 mph during a hurricane. Blizzards, including one in early January 2018, sometimes deliver 70-mph wind gusts to the region.

When bad storms do blow through, pitched residential roofs pose a unique challenge because the wind is deflected upward as it strikes the shingles. This phenomena, called "wind uplift" often exerts enormous pressure on the windward side of the roof. The highest pressures are frequently found along any changes in the roof's surface, including eaves, ridges, hips and rakes.

It is important to note that damage can also be caused by negative pressure on the leeward side of the roof. High winds passing over the roof can create a suction effect that may lift and loosen shingles as well. Either scenario may wreak havoc on a roof that is improperly installed or fabricated from inferior materials. Aging roofs are also susceptible to wind damage.

After a severe storm, it is not enough to look only at the side of the roof struck by the incoming winds. Rather, it is necessary to look for 1) lifting of shingles by air driven under the shingles, and 2) loosening from a suction effect on the leeward side of the roof.

The wind resistance of asphalt shingles is established through ASTM D3161-09 testing. Class A shingles can pass a 60-mph wind velocity test, Class D shingles can pass a 90-mph wind velocity test and Class F shingles can pass a 110-mph wind velocity test.

Factors that impact wind resistance - It is important to note that many factors may impact the actual wind resistance of an asphalt shingle roof, including:

  • Variations in wind intensity, duration and turbulence
  • Ambient temperature
  • Roof slope
  • Contamination by debris and dirt
  • Improper fastener placement and alignment

The highest wind gust during a storm is only one concern. Winds that ebb and flow during a sustained storm may increasingly weaken bonds until shingles break loose. Also, other buildings and nearby obstructions may cause winds to swirl. This extra turbulence may do more damage as winds assault the roof from different angles.

The Asphalt Institute notes how important the seal is between shingles. An article in the organization's magazine says, "the key to wind performance is how well the top shingles seal to the shingles below and how well that seal is maintained over time when exposed to the elements." The author goes on to state that both the toughness and flexibility of shingles relates to performance in a windstorm.

Fortunately, one well-known roofing manufacturer, Owens Corning, has developed a patented "TruBond" sealant that is used on its Duration series shingles. In addition to the proprietary sealant, there is a specially woven fabric strip located along the "nailing line" that provides excellent gripping power.  The SureNail technology is so effective that the manufacturer warranties qualifying roof systems in winds up to 130 mph for 15 years.

Incremental roof damage

When high winds send a tree crashing into a roof, the damage is often obvious. The same is true when such winds tear shingles right off the roof deck. However, high winds can impact a roof in far more subtle ways. For example, wind uplift can break the bond of the adhesive sealant, and the shingle can lay down flat once the storm passes. However, that broken seal may allow future episodes of wind-driven rain to get under the shingle and, possibly, all the way to the wood underlayment and/or framing. Sometimes, leaks will even appear inside the home. The importance of shingle sealants is also highlighted in an RCI post.

More insidious and sneaky kinds of wind damage occur over time. For example, high winds in a blizzard may slightly loosen shingles. A year or two later, high winds in a tropical storm may loosen them further. As the shingles continue to age, they may become more brittle and more vulnerable to curling and cupping. Years later, yet another windstorm might tear such shingles completely off the roof.

Upon closer inspection, wind-damaged shingles may be creased just below the shingles immediately above. Or, they may be curled or torn. A roof's perimeter is often most vulnerable to this incremental damage. Over time, wind uplift may cause a phenomenon known as "chain peeling" as long stretches of roofing come loose.

Incremental wind damage is often made worse by installation failures. For example, dirt and debris that sticks to the adhesive strip on an asphalt shingle will compromise performance. Erratic nailing may make certain shingles far more vulnerable to wind uplift.

Since some wind damage may not even be visible, it is important to have a certified roof inspector look closely for evidence of such damage, either after a severe storm or during a periodic inspection. Semi-annual inspections in the spring and fall help detect damage at an earlier stage when the remedies are often simpler.

Preventing Wind Damage

To maximize roof performance in high winds, you need two things - quality, wind-resistant roof components and expert installation by a manufacturer-certified roofing contractor.

Use quality roofing materials

First, note that architectural shingles (also called composition shingles) are heavier and therefore more wind-resistant than traditional 3-tab shingles. The difference between 3-tab and architectural shingles is illustrated by their respective wind ratings. Certain 3-tab shingles may have a wind rating as low as 60 mph. Compare this to the 130 mph rating of Duration composition shingles from Owens Corning.

The most wind-resistant architectural shingles are engineered to remain flexible in the bitter cold so they don't break in the high winds that accompany blizzards. At the same time, they must also be engineered to stand up to summer heat waves. Also, high-quality adhesives can maintain a strong bond between shingles in sub-zero cold and triple-digit heat. Ultimately, a well-engineered asphalt shingle is secured by high-quality adhesive strips and proper nailing.

Arrange for expert installation

A roofing contractor that is certified to install a manufacturer's roofing products knows how to install a roof system in a way that maximizes performance. It takes discipline and experience to fasten shingles to the roof deck for maximum performance.

Nails must be aligned along the reinforced nailing strip on each shingle. Fasteners that miss their mark will not properly secure the shingles. Proper six-nail installations are typically more wind resistant than four-nail installations. Nail guns must be set at the right pressure to successfully drive nails through the shingles without driving them too far.

Ultimately, you want the peace-of-mind that comes from a roof installation that will stand up to the winds it is rated for. In this part of the country, a properly installed 130-mph roof will handle just about anything that Mother Nature throws at it. The nation's leading roofing manufacturers specify how their products are to be installed. Certified contractors commit to installing roof systems to spec. A little extra effort and discipline during an installation can go a long way toward better securing your asphalt shingles in high winds.

Roofing companies certified by the manufacturer rely on their experienced, professional crews to install asphalt shingle roofs strictly in accordance with manufacturer specifications.

Understanding Warranty Coverage 

While regular manufacturer warranties usually only pertain to the shingles themselves, "total protection" warranties apply to other roof components as well. This means that total protection coverage gives you the protection that extends to flashing, underlayment, ice barriers and other components of your roof system.

Wind warranties

It is important to understand manufacturer wind warranties. They often warranty a roof in winds up to certain speeds, and for a certain number of years. For example, Duration shingles from Owens Corning are wind-rated at up to 130 mph for 15 years.

Roofers in the Owens Corning Contractor Network are eligible to offer a Platinum Protection Roofing System limited warranty that includes lifetime workmanship coverage to the original homeowner. Owens Corning offers no workmanship coverage when a non-certified roofer performs the installation.

Four or six-nail installation - In some cases, manufacturers offer better wind warranties to homeowners that choose six-nail installation rather than four. For example, when four nails are used to fasten each "Berkshire Collection" shingle to the roof deck, Owens Corning includes wind damage coverage in winds up to 110 mph. However, when six nails are used, wind damage is warrantied up to 130 mph.

Only certified roofing contractors are eligible to offer the best full system warranties offered by the major manufacturers. Understandably, companies like Owens Corning are more willing to back up their roof systems when they are installed by capable contractors. Certified contractors meet precise standards, and they also agree to participate in ongoing education.

Ideal warranties

Complete roof system warranties are the way to go because they give you the best protection.

Beware of warranties that only cover the asphalt shingles themselves. By comparison, full roof system warranties cover all the roof components that are designed to function as a single, well-integrated system.

The differences in manufacturer warranties are often substantial, including the non-prorated term of coverage - the period of time during which the manufacturer will replace a product at no cost. For example, when a non-certified roofer installs Duration shingles from Owens Corning, the non-prorated coverage period is 10 years. However, when a homeowner uses an Owens Corning Platinum Preferred Contractor, the non-prorated coverage period is 50 years - five times as lon

There are also differences in the transferability of warranties. If you intend to remain in your home for a long time, you can take full advantage of a warranty that provides "lifetime" coverage to the original owner. By comparison, a transferable warranty can pass from the original owner to the new owner. Note that such a warranty cannot typically be transferred to a series of future owners.

Finally, it is important that your roofing contractor register the warranty with the manufacturer and provide you with a proof of purchase.

BRAX Welcomes the Opportunity to Serve You

The team at BRAX Roofing understands how quality roofing products and superior workmanship limit the potential for wind damage to your roof. When you invest in a new roof system, you want the peace-of-mind that comes superior manufacturer warranties, and from working with a contractor you can trust.

BRAX Roofing is an experienced, reputable roofing contractor proudly serving homeowners in Maryland, Washington D.C. and Virginia. We offer everything from routine roof inspections and periodic maintenance to full roof replacements. We are also proud of our status as an Owens Corning Platinum Preferred Contractor.

When your roof is damaged by high winds, trust BRAX to take care of emergency repairs. We'll quickly secure and stabilize your roof as necessary. When applicable, we will also help you with your insurance claim.

To arrange for a complimentary inspection by a certified roof inspector, please contact us today!

About The Author

Ben Matthews is a managing partner at BRAX Roofing, a multi-faceted company that focuses on residential and commercial roofing throughout Maryland and Washington DC. Having obtained the highest certifications in roofing from leading manufacturers around the country, Ben takes pride in providing BRAX Roofing customers with top-quality exterior home improvement service and expertise.