How are class 4 shingles rated?
Shingles are rated for their ability to resist hail damage. The class 4 shingle is the one that will be highlighted in this post. Each manufacturer has shingles on the market that have been tested and rated by underwriters’ laboratories using specific units of standards and testing measurements that qualify as hail impact resistant shingles.
The Class 4 Shingle
Currently the highest class of asphalt shingles is the class 4 shingle which will carry at least the U.L. 2218 steel ball listing. I’ll share on several test that can be performed in this category for the highest performing impact resistant shingles on the market today. This product is of great interest to insurance companies and homeowners alike. I’m hoping to see greater test and shingle changes in the future to create a class 5 product. Only time will tell. The class 4 shingle is tested with a 2” steel ball that strikes the same area twice. This ball is dropped from a distance of 20’. The class 4 product must show no evidence of punctures, tears, cracks, splits, ruptures on top or bottom. In addition, this product will be observed with 5x magnification to ensure that it has passed the test. https://www.youtube.com/watch?v=ADD2m2FeVOQAre There Any Other Tests Available to Determine Class Rating?
Another test that is sometimes used is the ice ball test which began in the year 2000. The ice balls are propelled to match the same speed as a free falling ice stone of the same size. This test requires that the targeted area on the shingle is impacted 3 times as opposed to the steel ball test of only 2 times. This is a pass or fail test. To pass this test, the shingles must show no immediate visual evidence of compromise to the fiberglass mat.
Functional Damage to Shingles
In a previous blog, I mentioned functional damage of a roof system, and I’d like to expound on that briefly. It is important to clarify that when a hail stone impacts a roof system it may or may not damage it. For instance if you’ve recently installed a class 4 hail impact resistant shingle on your home and your roof was impacted by 2-1/2” hail stones, there is a chance that your roof sustained no functional damage. However, if your roof is made up of a 10-year old class 4 shingle it probably did sustained damage. I’ll share more on this in a moment, but for now let’s describe what is functional damage and why.
A Current Example of Functional Damage
From the recent storm in Highlands Ranch we’ve inspected some roof shingles that have been torn or have sustained small punctures. The photo above is from Highlands Ranch and many Denver roofers have seen what you can now see. This image illustrates all of the areas on the shingles that were impacted by hail. Many more of the roofs that we have inspected had fiberglass mats that were bruised and had small fractures from hail stones which have decreased the serviceability of the roof system. Whether there were punctures or only bruises, these roof systems should be replaced.Effects of Aging on a Class 4 Roof
Older class 4 roof systems can sustain damage from 2-1/2” stones. As asphalt ages it becomes less pliable and more brittle. As a result, it no longer has the ability to transfer impact energy and the mat is damaged and/or punctures occur to this system. Most insurance companies recognize this and only recognize a class 4 shingle to provide a measure of protection for only a decade or less. Class 4 shingles are great, but again they are not hail proof and their serviceability diminishes over time. Nevertheless, I highly recommend installing a class 4 asphalt shingle.What About Metal Class 4 Roofs?
In most cases, I will not recommend installing a class 4 metal roof system. Many insurance carriers have clauses in their property coverage pertaining to metal roofs which state that they don’t owe for cosmetic damage to a metal roof system. This photo shows cosmetic damage which is highly visible from the ground. We took this photo from the ground level. If a hammered metal roof is the desired look that you were longing for, then you’ll be pleased with the hail hits on your metal roof system. In most cases it would take baseball sized hail to create functional damage to a steel panel. In some instances it would take larger than softball sized hail to puncture the panels or to break loose the seams. Metal roofs are durable, but the flip side to this is that you could be stuck with an ugly, dinged up roof if the metal doesn’t sustain large enough damage for it to be replaced.
