Observe: This visitor put up 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, Normal Contractor licensed in North Carolina. Mr. O’Leary additionally serves as a guide for engineering corporations concerned with wind injury 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 necessary step in investigating wind injury 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” Handbook).
The traditional strategy for many years was to conduct what is known as the “1-finger take a look at,” as proven within the image under. 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, you need to achieve this beneath the “worst-case” situation (the standard strategy when testing the efficiency of an merchandise). To perform this for shingles is to check them when they’re chilly or a minimum of cool, which mimics “storm-like circumstances.”
Accepted follow, that violated seal strips that have been bonded to the underside of the overlapping shingle, is wind injury. 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.”
They now imagine that any time a seal strip is violated, the wind might be enough 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 will not be proof of wind-caused injury.
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 gap 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 pace will increase, a second crease will kind the place the lap between these two shingles. HAAG included their take a look at stand of their paper to show this. Nonetheless, they didn’t reveal the wind pace they used of their take a look at.
Earlier this yr, 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 footage that the blue arrow under is pointing to are pictures taken from that video.
Observe that the wind pace proven within the insert and the enlarged model is 119 mph. Provided that seal strips wind score is barely 60 mph, why would they run the take a look at at 400% of the 3-tabs wind? Based mostly upon a easy understanding of physics, it seems that to be able to get the wind power as much as sufficient to create a crease on the lap of the shingles, they needed to go as much as 119 mph to attain this.
To claim that the shingle will completely fold over on the identical time the 60-mph rated seal strip releases, when their precise take a look at appears to disprove this, it’s a drawback.
In conclusion, easy physics appears to inform me that the preliminary crease would happen beneath the overlap, not on the overlap, the place it could be seen. I agree that when the wind pace will increase sufficient, it could trigger the shingle to proceed to fold over on itself, making a second crease, which is instantly 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 discovered over many years of coping with roofing producers, will not be sturdy sufficient to fold a really versatile tab over onto itself.
