27 May WHY ARE SHINGLES BLOWING OFF MY ROOF?
Every windstorm shingles blow off your roof. You gather one or two from your driveway or the back yard. Frustrated, you cry out in despair, “Why?” Well, good question! Let’s answer it. Here are 4 possible reasons that shingles are blowing off your roof:
1. A high-wind event
2. Low wind-rated shingles
3. Poor installation
4. Winter installation
A High-Wind Event—Yes, it’s obvious that winds are the cause of shingles blowing off the house. However, the reason why could be traced back to a high-wind event. A high-wind event might not blow shingles off immediately but can simply lift shingles up separating the seals of the shingles known as mastic, or the shingles can pull through the nails that are supposed to hold them in place. If you have experienced a high-wind event of 60 mph or higher in your area—often associated with some thunderstorms, a straight-line wind, or a tornado—it’s possible that your roof has experienced the beginnings of wind damage. After the mastic separates or shingles pull through the nail, shingles are more vulnerable to blowing off as a result of any kind of wind event, even at much lower speeds.
Low Wind-Rated Shingles—This one is simple. The wind rating for shingles starts at only 60 mph. Here in Oklahoma wind speeds reach 60-70 mph at least once or twice each year. Three-tab shingles have the lowest wind rating of all shingles and are most susceptible to blowing off. If your shingles have a low wind-rating, this could explain why shingles are blowing off your house.
Poor Installation—It really doesn’t matter if it’s a shingle roof, a kitchen, or even a vehicle when things are installed improperly, problems will occur. How can shingles be installed improperly resulting in blow-offs? The answer is “nail placement.” If shingles are not nailed in the common bond area or are nailed too far from the edges, shingles then lose the ability to withstand high winds.
Winter Installation—For a shingle to seal properly, it needs warm air and heat from the sun. Manufacturers recommend installing roofs in temperatures no lower than 40 degrees Fahrenheit. Without the necessary heat to activate, the mastic strip doesn’t attach itself to the shingle. Since the mastic doesn’t attach, shingles are sitting on top of each other. Next, as moisture builds up on the mastic strips, they start to collect dirt and dust. Over time, when it warms up enough for the mastic strip to seal, the seal cannot seal as intended because of the dirt and dust. A good example of where this can occur is a construction site where new homes are being built. When a roof is installed in the wintertime, as we talked about, the shingles don’t seal. That dirt that has been dug upstarts to blow around and settles underneath the shingle. When the dirt sticks to the mastic strip, a good seal is nearly impossible to achieve at that point.
It’s likely that one of the four reasons given—or even a combination of these reasons—explains why shingles are blowing off your roof. If you are experiencing shingles blowing off your house, don’t forget that this wind damage is covered under your homeowner’s policy. Also, if you want a diagnosis of what the problem is and solutions, we at Robert Moore Construction can help with this.