Your asphalt shingle roof is designed to protect your home and belongings from damaging elements. If you are not careful, however, it can fall victim to one of nature’s most unpredictable forces – the wind. When a severe storm comes through, strong, powerful winds can cause devastating damage to your roof, leaving you with a giant, costly mess.
Today, we share a guide to asphalt shingle roofs and their resistance to wind damage. Keep reading to learn more!
How Wind Interacts With Asphalt Shingle Roofs
One thing about the wind is that it moves in random, unpredictable directions. It swirls up, down, sideways and in circular patterns at different speeds. This is an effect of the changes in temperature and pressure in the Earth’s atmosphere and variations in the land’s topography and terrain.
When it comes to roofing structures, wind acts in a fairly predictable manner. For example, when it hits the side of your home, it travels up and over your roof with varying degrees of uplift pressure. Uplift pressure is highest at the corners of the roofline – also called the eaves – making this part of your roof vulnerable to wind damage. When wind moves across the surface of your roof, suction pressure is created, which can lift your asphalt shingles off the deck.
Factors That Influence How Wind Affects Asphalt Shingle Roofs
Strong winds can cause you thousands of dollars in roof-related damage. To preempt such costly expenses, it is important to be aware of the factors that influence your roof’s susceptibility to wind damage.
Installation
A fundamental factor that determines a roofing structure’s resistance to wind is the quality of its installation. The aspects that matter the most are:
- Nailing: Because the nails attach the asphalt shingles to the roof deck, improper nailing can significantly diminish the strength and durability of the roof. As a result, it makes the shingles susceptible to blow-offs during high winds. In addition to positioning the nails correctly on the shingles, roofs must also use the correct type of nails.
- Overhang: Overhang is the section of the roof that extends over the exterior wall. The end of a shingle should have an overhang of 1 to 1.5 inches – or even less if drip flashing is installed. Too much overhang can cause your shingles to easily blow off in the wind.
- Pitch: The roof pitch, sometimes referred to as slope, determines the volume of air that passes over and gets under the roofing. A wind-resistant roof typically has a pitch between 4/12 and 6/12.
Materials
The materials used on the roof also have an impact on its overall resistance to wind damage.
- Shingles: Shingles are classified in different categories depending on their wind resistance. For example, Class D shingles can resist uplift at wind speeds of up to 90 miles per hour (mph), whereas Class G can withstand winds of up to 120 mph.
- Sheathing: The sheathing is primarily designed to distribute weight evenly across the roof, but it also influences the strength of the shingles. A thick sheathing is better at resisting bowing between the rafters or trusses than a thin sheathing. When made with plywood or oriented strand board (OSB), it makes the home two to three times better at withstanding persistent forces of wind.
- Deck: During a high-wind event, the roof deck is expected to resist wind uplift forces. The choice of material and how it is attached are key to the roof’s structural performance. The thickness of the deck also contributes to its resistance to pull-through, which is when the deck comes off of the roof framing.
Age
As an asphalt shingle roof ages, its performance weakens. Nails loosen, metals rust and shingles lose their granules. The weaker the roof becomes, the more vulnerable it is to all sorts of weather-related damage. Naturally, an asphalt roof nearing 20 years old is more likely to experience the adverse effects of wind than a relatively new roofing system.
Signs of Wind Damage on Asphalt Shingle Roofs
After a severe weather event, some signs of wind damage may be visible and others not. But if you know what to look for inside and outside of your home, you may be able to spot and address them before they become more problematic.
So, how do you find outdoor evidence of wind damage? Once it is safe, take a quick stroll around your property for fragments of shingles, and scan your roof for the following:
- Areas where shingles are slightly lifted. This indicates that seals on the roof may have been compromised.
- Narrow lines near the edges of the shingles. This tells you that they may have been flipped up and creased.
- Scratch marks across the roof surface. Oftentimes, this is a sign that windswept debris has scraped the shingles.
- Debris such as branches, twigs or broken glass in the gutters.
- Cracked flashing around the chimney and other roof penetrations.
- Damage to ridge and soffit vents.
It is also critical that you inspect the interior of your home after a severe storm for potential wind damage. Here is a simple guide by a roof replacement specialist:
- Go to your attic while there is still daylight.
- Check for leaks and dark-colored stains on the underside of the roof. Do not forget to inspect the floor for water damage. Use a flashlight for a more thorough checkup.
- Turn the lights off in the attic and scan for areas in the decking where daylight is visible through the roof. Holes, gaps or cracks in the roof could indicate that extreme damage has occurred.
- In the finished living spaces, check for stains or discoloration on the ceilings and walls.
Need Professional Help With Your Roof?
ImproveIT! of Atlanta provides top-rated roofing services, from routine inspections to storm damage repairs and full replacements. Whether you live in Alpharetta, Marietta or Sandy Springs, GA, our team of professionals can help you find the roofing solution that is best suited to your needs and budget. Give us a call at (770) 612-5635, or fill out our convenient online form to request a free, no-obligation estimate today.
