Finding pieces of your roof on your front lawn is never a good time. Asphalt shingles have been known to blow-off from time to time during windstorms and, in many cases, this could have been prevented. How? Developments in roofing practices and materials have been ongoing, especially to provide better protection against high winds blow-offs...
Too frequently, we see wind damage occurring as a result of improper installation. That is, namely, 'high-nailing' of asphalt shingles. When shingles are high-nailed, the shingle will not lay flat on the roof surface (as intended by the manufacturer) and, as a result, the bottom edge sealant band is unlikely to properly seal. This means that even with moderate gusts, the shingle lifts easily and begins to flap in the wind until it tears off.
"What exactly is high-nailing," you ask?
High-nailing implies that the nails are not installed in the correct area on the shingle (too high). The asphalt shingle manufacturer has been kind enough to provide a 'nailing line' that guides the installer during application. Nails must be installed on this line within an allowable range. Even an inch above the line is not acceptable. When the nail is placed on the line as intended, it is securing both the shingle that is being nailed and the underlapping shingle beneath at the same time. Further, each shingle should receive at least 4 nails - or more on steeper slopes. When the basics of installation are properly adhered to, the shingle performs well.
With the advent of pneumatic air nailers, installers must also be careful to ensure nails are seated properly during installation. If not set to the proper air pressure, a nailer can cause the nails to 'blow through' the shingle (partially or completely). Alternatively, poorly seated nails that are not sitting flat could result if the air pressure is too low. Air roofing nailers have a simple adjustment mechanism to help compensate for over-driven or under-driven nails. Unfortunately, during many of our repairs over the years, we've found that this easily correctable issue is often the cause of wind damage that could've otherwise been prevented.
If any asphalt shingle roof is beginning to crack, curl or show similar signs of wear, it is not likely to perform well with strong gusts of wind. Cracking and curling shingles are easily torn off by wind. In these cases, it is simply a matter of having the roof replaced before it gets to such a point of failure.
Newer asphalt shingles have a generous bead of sealant on the underside to create a bond once heated by a few sunny days. Once installed, the sealant melts and adheres the shingle to the substrate below, making for good protection against wind uplift. This bond is tough to break, even with higher than normal winds. Of course, the manufacturer does indicate a wind velocity limitation with any product. For example, IKO Industries - a leading Canadian manufacturer of asphalt shingles - indicates a 177 km/h wind rating for their standard architectural shingle (view here).
As a result of recent innovations, 'high-wind' asphalt shingles with the addition of a reinforced nailing strip have made their way to the market. These shingles, manufactured by IKO, are rated for an even higher wind velocity of 210 km/h. Besides the higher wind rating, this reinforced strip is extra peace of mind as we don't always have those hot sunny days when we need them to ensure our shingles seal down immediately after installation (early spring or late fall). A reinforced nailing strip provides added tear resistance while the sealant band adheres the shingle in place (check out Dynasty Asphalt Shingles from IKO here).
Alternative Materials (Steel Roofing)
In some cases, a steel roof is a serious consideration for the best wind-resistant solution. Although steel roofing is more costly per square foot, the right system will provide superior protection against wind uplift when installed properly. This is due to the fact that steel roof systems can be interlocking and screwed in place, depending on the which profile is selected.
To view steel panel profiles, have a look at some of our preferred steel roofing manufacturers supplying Sudbury:
If you'd like to discuss a high-wind solution for your project, get in touch with us!
In the event of wind damage to your roof, big or small, our team provides emergency leak-mitigation repairs to help keep you dry following windstorms. Call for service (705) 592-2129.