Observe: 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, Normal Contractor licensed in North Carolina. Mr. O’Leary additionally serves as a guide for engineering companies concerned with wind harm from hurricanes and tornadoes. He could be contacted at 919-219-4099 or through e-mail at mailto:[email protected].
For many years, an vital step in investigating wind harm to shingles was to “examine 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 traditional method for many years was to conduct what is named the “1-finger check,” 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 examine seal strip efficiency, you need to achieve this beneath the “worst-case” situation (the standard method 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 observe, 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 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 shouldn’t be proof of wind-caused harm.
They state that with newer, very pliable shingles, the crease could also be tough 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 will likely be on the nail line, which on this instance is a little bit 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 pace 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 pace they used of their check.
Earlier this yr, I attended the web, 5-year renewal for the “HAAG Licensed Inspector – Wind” I used to be offered with the precise video of the “laboratory testing” they performed. The 2 footage that the blue arrow under is pointing to are photographs taken from that video.
Observe that the wind pace proven within the insert and the enlarged model is 119 mph. On condition that seal strips wind ranking is just 60 mph, why would they run the check at 400% of the 3-tabs wind? Primarily based upon a easy understanding of physics, it seems that to be able to get the wind drive 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 claim that the shingle will completely fold over on the similar 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 will be seen. I agree that when the wind pace will increase sufficient, it may 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 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).