Be aware: This visitor submit is by Lewis O’Leary, who has served as each a forensic investigator and restoration contractor since Hurricane Camille (1969). He has a level within the fields of Mechanical Engineering and Structure, is a “Constructing Envelope Marketing consultant, Stage 2, licensed by the Constructing Envelope Science Institute, a “HAAG Licensed Inspector – Wind”, is a North Carolina Licensed Public Adjuster, and is a design/construct, Common Contractor licensed in North Carolina. Mr. O’Leary additionally serves as a advisor for engineering companies concerned with wind harm from hurricanes and tornadoes. He could be contacted at 919-219-4099 or by way of e-mail at mailto:probuil@aol.com.
For many years, an vital step in investigating wind harm to shingles was to “verify sealant bonding and fasteners” (as set out within the above image, which is proven on web page 59 of the “HAAG Licensed Inspector – Residential Roofs” Guide).
The standard method for many years was to conduct what is named the “1-finger check,” as proven within the image beneath. The adjoining picture is an instance of such. Taking notes from my discussions with the roofing merchandise producers, I additional outlined this course of by setting out the notion that if you wish to verify seal strip efficiency, it is best to achieve this beneath the “worst-case” situation (the traditional method when testing the efficiency of an merchandise). To perform this for shingles is to check them when they’re chilly or not less than cool, which mimics “storm-like situations.”
Accepted follow, that violated seal strips that have been bonded to the underside of the overlapping shingle, is wind harm. Nonetheless, in 2017, HAAG Eng. reversed its place on this and produced the hooked up paper entitled “Misconceptions of Wind Harm to Asphalt Composition Shingles.” 1
They now consider that any time a seal strip is violated, the wind will probably be ample to fold the tab again sufficiently to trigger a “creased, folded or lacking shingle.” Particularly, this paper units out the next:
A shingle that’s merely not adhered and isn’t creased, folded, torn, or lacking shouldn’t be proof of wind-caused harm.
They state that with newer, very pliable shingles, the crease could also be troublesome to see, however placing your hand beneath the shingle might assist to search out it. A basic error of their logic is that if a crease is created, it is going to be on the nail line, which on this instance is somewhat over 1” up slope from the decrease fringe of the shingle (see the space between the 2 white arrows within the image above).
That distance is transposed to the picture above, the place these white arrows correspond to these on web page one. Merely put, the preliminary pure fold line (aka the pivot level) will kind beneath the overlapping shingle, which is hidden from view. Because the wind velocity will increase, a second crease will kind the place the lap between these two shingles. HAAG included their check stand of their paper to show this. Nonetheless, they didn’t reveal the wind velocity they used of their check.
Earlier this 12 months, I attended the web, 5-year renewal for the “HAAG Licensed Inspector – Wind” I used to be introduced with the precise video of the “laboratory testing” they carried out. The 2 photos that the blue arrow beneath is pointing to are images taken from that video.
Be aware that the wind velocity proven within the insert and the enlarged model is 119 mph. Provided that seal strips wind ranking is simply 60 mph, why would they run the check at 400% of the 3-tabs wind? Based mostly upon a easy understanding of physics, it seems that in an effort to get the wind pressure as much as sufficient to create a crease on the lap of the shingles, they needed to go as much as 119 mph to realize this.
To say that the shingle will completely fold over on the identical time the 60-mph rated seal strip releases, when their precise check appears to disprove this, it’s a downside.
In conclusion, easy physics appears to inform me that the preliminary crease would happen beneath the overlap, not on the overlap, the place it might be seen. I agree that when the wind velocity will increase sufficient, it will possibly trigger the shingle to proceed to fold over on itself, making a second crease, which is quickly seen when inspecting a roof. Nonetheless, expertise tells me that the overwhelming majority of 3-tab shingles will fail by about 75 mph, which, I’ve realized over a long time of coping with roofing producers, shouldn’t be sturdy sufficient to fold a really versatile tab over onto itself.
1 C.R. Lopez, J.S. Goode, S.R. Morrison, Misconceptions of Wind Harm to Asphalt Composition Shingles, IIBEC Communications (Dec. 28, 2017).
