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Home Architectural: News, Designs & Projects Guide to Choosing the Right Roofing for Hail

Guide to Choosing the Right Roofing for Hail

Roof for hail resistant feature image

Are there any truly hail resistant roofing materials out there? At this point in time, there is no complete, 100% hail resistant roofing solution. Hail stones can travel at speeds up to 110 mph and grow to softball-sized stones. Aside from a concrete slab, no traditional roofing materials can come away from these types of hail stones without being dented or damaged. While there are suitable measures that can be taken to prevent damages from most hailstorms, the largest hail stones will cause damage to even the most durable of roofing systems.

Understanding Hail Impact on Roofing

In order to understand how well a roofing material will hold up against hail, it is first important to understand how these materials are judged. A latest test for measuring the effectiveness of a roofing material against hail damage is the UL 2218: Standard for Impact Resistance of Prepared Roof Covering Materials. This test uses a steel ball to impact various locations on a particular assembly including edges, seams, or unsupported joints or sections. While this test provides one of the best gauges of how a roof will hold up against a hail storm, a steel ball is not a hail stone, and even this extensive test does not guarantee a material or product will hold up against a severe hail storm.

The Role of UL 2218 in Hail Protection

While UL 2218 testing is one of the best ways to gauge a material or product’s ability to hold up against a severe hail storm, hail can still ultimately damage or penetrate many of even the toughest roof systems. The reason behind this is simple: a 1 ½ pound hail stone (3.25 inches) can travel at speeds of up to 105 mph. The power behind these hail stones is incredible. While a material may resist a single impact, multiple impacts in the same location will eventually cause damage or penetration of the roofing materials.

Fortunately, baseball-sized hail stones don’t happen every day. For the majority of homes, a Class 4 UL 2218 rating will be sufficient in protecting your home from roof penetration due to a hail storm. A Class 4 test involves a steel ball weighing 1-2 pounds being dropped from a height of 12 to 20 feet on the same location of the assembly. This is considered by most professionals (and insurance companies) as the highest level of protection a roof covering material can provide.

Metal Roofing for Hail Protection

Metal roofing has always been known as one of the toughest materials available to use for a roof, and most metal roofing panels carry Class 3 or 4 ratings. However, just choosing any metal roof may leave many owners with regrets after the next big hail storm. This has to do with the testing itself. While UL 2218 (and other testing standards) measures the ability of a material to stand up to rips, tears, holes, and penetrating issues, it does not consider the visual appearance of the material once the testing is complete.

In other words, your roof may still be 100% structurally sound after a severe hail storm, but could also look like someone took a baseball bat to every inch of your roof. Beyond a visual nuisance, some insurance companies who provide a discount for metal roofing will not cover cosmetic damage caused by hail as your roof is still intact and structurally sound.

Roof for hail resistant

Cosmetic Hail Dents & Dimples

To minimize cosmetic damage, you need to take into account the design of the panel itself. Many standing seam metal roofs have large, flat surfaces that show smaller imperfections due to their smooth uniform appearance. Breaking up a standing seam panel with striations or ribs will help minimize the visual impact of dents, as well as help with expansion and contraction in areas prone to temperature swings.

One of the best panel styles at minimizing the visual impact of dents from hail is the corrugated roofing panel. The design of a corrugated roofing panel makes it extremely durable as the corrugations greatly increase steel’s already impressive tensile strength. This improved strength makes corrugated panels harder to have damage inflicted upon their surface. If imperfections are created, the corrugated roofing panels have the added benefit of breaking up the sight lines and hiding these small visual imperfections better than other panels styles. For these reasons, corrugated roofing panels are among the most durable and best options for a hail resistant roof in areas subject to hail storms.

Debunking the Myth: Is Thicker Steel Better?

A common misconception when it comes to protecting a structure against hail damage is the thickness (gauge in the case of steel) of the material. Metal panels are made of a series of layers — some using galvanized coatings while others using galvalume coatings to create a combination of metals, primers, and paint coatings. These materials are created in steel mills that use various techniques to create the best possible product for the widest potential series of use cases.

While thicker steel is often better at preventing dents and surface damage, it is also often less flexible than a thinner material that may dent easier, but is less likely to tear. While most metal panels ranging from 22 to 29 gauge steel offer a relatively similar level of protection, there is a difference in how each thickness will perform against different aspects of a hail impact.

Selecting Quality Metal Coils

Due to the extremely sensitive process of milling steel for roofs, the choice was made to use only domestic steel mills using the highest level of technology to mill the base steel, and to use the smallest measurements for the coils – something that is not common in the industry. This means that each roll purchased is required to have a minimum thickness to ensure that each panel run meets the requirements. Since steel coils are sold by gross weight (after application of paint and primer), many manufacturers choose maximum thickness for cost reasons, but this also prevents them from ensuring a consistent product.

Hail resistant roof

Choosing the Right Underlayment

An important factor in choosing a roofing envelope that holds up to most hail storms includes selecting the right underlayment material. Whether you are choosing a metal, shingle, shake, or tile roof, choosing the right underlayment should be a critical part of your decision-making process. Like visible roof coverings, underlayment materials are also tested for impacts. Often people spend a significant amount of time carefully choosing the surface of their roof system, without ever considering this second layer of defense. Underlayments can not only help protect your home from impact, but are also tested for water, air, and fire ratings.

Get Advice from Experts

Ultimately, there are a number of factors to consider when choosing a hail resistant roof. Choosing the right materials, selecting the right installers, and speaking to your insurance company about the actual coverage of your plan are among the most important choices to make. Other quick tips for designing hail resistant roofing include:

  • Maintaining a minimum roof slope of 6:12 has been known to help minimize hail damage
  • Use roof decking or well supported plywood sheathing materials under a tested underlayment.

While there are no true, completely hail resistant roofing solutions, choosing the right roof covering, along with a quality underlayment, will help your roof hold up against most of the strongest storms. Doing the research, speaking to professionals about your options, and making decisions on which factors mean the most to you and your home will help you choose the right hail resistant roof solution for your region.

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