Hail: Damaged Roofs - Inspecting and Identifying

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When analyzing a roof for hail damage, it is important to differentiate between damage caused by hail and damage caused by natural weathering. Additionally, manufacturing defects, damage during construction and/or damage occurring during transportation can often look much like hail damage.  

Damage to asphalt shingles from hailstones is typically one of two types:

  • Rupturing of the reinforcing mat

  • Loss of granules that exposes the underlying bitumen.

Rupturing of the reinforcing mat represents a potential loss in the shingle's water-shedding ability in that a ply of roof covering is removed by the rupture. The loss in water-shedding ability increases the potential for water to reach the roof fasteners, causing corrosion or the butted joints in the sheathing, permitting water to enter the interior of the building.

The loss of granules represents the potential for a reduction in the expected service life of the shingle. 

A wood roof that has been impacted by hailstones is typically easily recognized. As the hailstones impact the surface, impact marks where gray-colored oxidation and organic surface growths have been removed, are recognizable new features in the roof's appearance. However, impacts to wood roofs that do not split or puncture the wood are not considered to cause damage. Studies have shown that wood shingles and shakes that are impacted by a hailstone and do not split immediately upon impact are not prone to future splitting. 

After a hailstorm, check the trees, shrubs and plants around your home. If they are stripped of foliage, there is a possibility your roof is damaged. Also, if patio furniture, screens or roof vents are dented, there may be roof damage. 

Check your roof carefully. Be sure to cover any holes in your roof or broken windows so that water can not enter your home and damage the interior and your possessions.