From an engineering perspective, hail with sufficient mass, hardness, and impact energy can dent or rupture (tear) metal roofing materials. Haag Engineering began its ice ball impact testing program for roofing in 1963. Haag’s impact testing of metal panels in good to
Hail-caused distortions along panel seams can cause openings that allow water intrusion. Hail impacts at fasteners in unsupported seams can sometimes disengage these fasteners. Ruptured panels, disengaged fasteners, and openings along seams have been considered damage to metal roofing because the water-shedding capability had been compromised. Removal of protective coatings by hail (again, typically field-applied coatings) also occurs on occasion from hail impacts and has been considered damage to metal roofing as the service life of the roof would be reduced. The question that arises in these situations is the appropriate method of repair or replacement.
Engineers and roofing consultants are not adjusters and should remain focused in their investigations on the evidence they see at the site. Any inspection of a metal roof must focus on the basics. First, did hail fall at the site? Second, if hail fell at the site, when did it occur? Third, the size of hail that fell at the site should be documented along with the directionality of the storm(s), and if possible, a determination should be made regarding whether or not the property was impacted by multiple hailstorms. This can be accomplished by assessing spatter marks (where hail removes oxidation and grime) and dents on various surfaces including roofing materials, roof appurtenances, fencing, utility boxes, and claddings. Hail typically falls in a defined direction. Thus, one or two sides of a roof typically bear the brunt of a storm. If more than two vertical surfaces of a building are affected, this could indicate that multiple storms impacted the property. Spatter marks will fade with time and may last up to two years depending on exposure and other factors.
Engineers and roof consultants typically focus on what hail did and did not do when evaluating a property. For instance, they should note if the hail impacts dented roofing panels and to what extent. If inspecting experts find dented panels, then they should then determine whether this has adversely affected the useful life or the water shedding capability of the roof. This is accomplished by determining if impacts
Engineers and roof consultants are hired to document their observations and render opinions based on their expertise. They do not make coverage decisions because that is always the role of the insurance claims professional. As a result, it is critically important that the claims professional
Once the damage is determined to exist, reparability of metal roofs can be a complex issue and may require estimates from construction consultants or roofing contractors. Questions sometimes arise regarding whether or not dents have adversely strained the metal. If a dispute lingers over this issue, dented samples of the roof could be removed by a qualified roofer and inspected by a qualified engineer or laboratory professional.
Dating the approximate time frame of a storm can also be important. In this situation, the engineer should check weather records and inspect the roof for spatter marks coincident with dents to determine if the dents were from a recent storm. Weather service reports by third parties are another tool that can be utilized. An engineer should always look at the weather service reports in conjunction with what can be supported and documented by site conditions.
This is excerpted from “Testing Your Mettle”, which originally appeared in The CLM. The article was co-authored by Kevin Kennedy,
Justin Kestner, P.E.
President and CEO, Haag Engineering