Do you live in a wind-prone area? Whether the breeze seems to blow stronger down your street or your region has a high risk of hurricanes, you need to think about your roof a little differently. You might choose an alternative to the traditional asphalt shingle, opting for metal panels instead. But if you do have a shingle roof, it needs to be installed with special attention to its wind resistance.
That’s where high wind roofing nails come in. How do you know whether you need them on your roof?
It’s All About Resistance
Withdrawal resistance is defined as the amount of force that’s necessary to remove a fastener from its embedded location. High resistance indicates that the nail has strong holding power. High winds can tug at roofing materials with surprising force. If a roofing nail has low withdrawal resistance, it can easily be pulled out in a windstorm or by a series of gusts.
Have you noticed that sometimes, it’s easier than others to pry a nail out of a board using a hammer? There are several factors that play into this, including the length of the nail and the material that the board is made of. These factors influence the nail’s withdrawal resistance.
Still, though, have you ever tried to pry a screw out of a board using the claw of a hammer? It’s next to impossible to do. If you have the strength to do it, it will demolish the board. The way that a screw digs into the board and displaces the wood fibers gives it a high withdrawal resistance.
Screws vs. High Wind Roofing Nails?
Screws are typically used to secure metal roofs to the underlayment. They hold down the heavy material and keep it in place for longer than nails.
However, screws aren’t generally recommended for use with asphalt shingles. Although they have a high withdrawal resistance and hold well, they create tiny gaps in the substrate, which can let precipitation in.
Ring Shank Fasteners
Ring shank fasteners are generally preferable for roofing. The ribbed protrusions create friction within their embedded location. This gives them a high withdrawal resistance. In fact, a ring shank nail has twice the withdrawal resistance as the same size smooth shank nail.
This type of fastener is similar to a screw but doesn’t have quite as much withdrawal resistance. It can be driven into the substrate with a hammer or nail gun and doesn’t require a screwdriver.
Wind-prone areas may have specific building code requirements for the types of roofing nails to use. For example, it is often recommended that fasteners with a withdrawal resistance of at least 25 lbs at 73 degrees be used for areas that see winds of 90 to 100 miles per hour. If a region expects wind speeds of greater than 120 miles per hour, fasteners with a 30-lb withdrawal resistance should be used.
The Pattern Is Important
The way that you install the fasteners is just as important as the type of high wind roofing nails that you use. In areas that are vulnerable to high winds, such as coastal regions, building codes require you to follow a specific pattern when installing roofing nails.
Since 2003, the International Building Code has required roofers to use six fasteners on each shingle in areas with wind ratings of 110 miles per hour or greater. If you’re using traditional 3-tab shingles, you’ll install two fasteners above each tab. Keep the fasteners away from the gap, or they’ll be exposed by the gap in the tabs above it.
Most architectural or dimensional shingles come with marked holes for the fasteners. This allows you to install them according to the manufacturer’s recommendations without any questions.
Worst Roofing Nails for High Winds
Smooth shank nails aren’t ideal for any roofing project, especially one that will be exposed to high winds. A smooth shank doesn’t generate much friction. Therefore, this type of fastener has a low wind resistance and can be pulled out of its location fairly easily. If high winds shift the shingles, over time they may pull out smooth shank fasteners too.
If you live in a coastal area with a sea breeze, you need nails that won’t corrode, such as stainless steel. Using corrosive materials can weaken your roof and make it vulnerable to blowing away in a windstorm. As salt air comes into contact with corrosive metals, it creates rust and weakens the metal. The nails lose their effectiveness and may not stand up to the next big storm.Most high wind roofing nails are made of stainless or galvanized steel.
Although most reputable roofers won’t use staples to attach shingles to a roof, some do because they’re easy to install. However, installing asphalt shingles with roofing staples usually doesn’t comply with building codes. They definitely won’t provide the strongest hold in a high risk situation and should be avoided. However, you may be able to use staples to secure the underlayment, depending on its material.
Other Considerations for High Wind Roofs
You’ll need a few different types of nails if you’re completing a full roof installation. Different fasteners are often used for flashing, sheathing and underlayment. Your roof functions as a comprehensive unit, and installation of all elements should follow building codes.
Shingles are most likely to stay in place when the roofing nails are inserted perpendicular to the angle of the roof and flush with the surface of the shingle. Don’t drive them in too deeply, or you’ll damage the shingle and increase the risk that it will tear away from the fastener in a windstorm.
Leaving a gap between the nail head and the shingle leaves room for movement when the wind blows. Over time, all of that wiggling reduces the fastener’s withdrawal resistance.
The shape, size and location of the building influence the roof’s susceptibility to wind damage too. You may need longer, stronger roofing nails if your home is especially tall or has roofs with a steep pitch. Areas with a sudden change in topography may also be more susceptible to roofing problems from high winds than other spots.
Finally, the underlayment should be enhanced in high wind areas. This might entail creating larger areas of overlap or sealing the roof deck. A self-adhering membrane will also protect the materials beneath the asphalt shingles. The reason for enhancing the underlayment is that it will provide increased water protection if a shingle is damaged and allows water to flow under the roof. You may even want to use roofing nails instead of staples to further secure the underlayment.
Are Your Shingles Lifting?
One of the telltale signs that your roof isn’t installed properly for the wind conditions in your area is shingles that lift during storms. If your asphalt shingles are bent or stand perpendicular to the roof in a storm, the nails have not been installed properly.
Work with an experienced roofer to remedy the problem. Making sure that your nails are the right style, length and material for your wind-prone roof will help it stay secure through many storms. But your roof can only safeguard you from the elements if it’s installed correctly. Using adequate roofing nails and other materials, especially in high-risk weather regions, is essential for protecting your home. Build your roof with us for long-lasting protection and peace of mind.