Why Are Shingles Blowing Off My Roof?


Why Are Shingles Blowing Off My Roof?When shingles blow off from a roof, most homeowners’ first questions are usually “Who can take care of this for me, how fast can they get it done, and how much will it cost?” But here’s the most important question a homeowner can ask:” What made my shingles blow off in the first place?”

Well, it was the wind of course… but here’s the thing: most shingles today have a “wind rating” of 110 miles per hour, and some go up to 130 miles per hour. That is, they are rated to stay on your roof up to a wind speed of 110 (or even 130) miles per hour. 75% of all TORNADOES have a wind speed of 112 miles per hour OR LESS.  So what we’re getting at here is that if your shingles are blowing off in a strong wind that isn’t a tornado, you might have a bigger problem. Shingles stay attached to roofs in two ways. First, there are the nails holding the shingle to the roof deck. Second (and very importantly), there is adhesive on the back bottom side of the shingle that makes it stick to the shingle right below it… this is called “the seal.”

Here’s what we found at a service call we went on at a Waukesha home. Upon arriving, the homeowners showed us one of the shingles that had blown off. It was immediately obvious that this shingle had been installed incorrectly: three of the five nails in the shingle had been placed too high up on the shingle, and not in the nailing strip. It didn’t provide adequate holding power, and that’s strike one. Next while up on the rooftop, the homeowners watched as we were able to lift up more than half of all the shingles we sampled… most of the “the seals” had failed. This can happen for a number of reasons, and it was true on this roof. That’s strike two. Finally, the shingles were clearly blowing off in winds far below their wind rating. That’s strike three.

Ultimately, the homeowners hired us to replace the entire roof, even though it was only 11 years old. With the seals failed, and the roof improperly nailed, it was clear that the roof was only going to become a continuous maintenance problem.