During extreme weather events, a combination of hail and rain can place high loads on a roofing system. N-J has investigated roof collapses where it was alleged that rain loads caused the roof to fail.

To evaluate the validity of the claim, N-J personnel obtained available weather data, determined the roof slopes, roof drain sizes, and estimated the peak amount of rain on the roof system. After estimating the water loads, N-J performed a structural assessment to see if the structure had sufficient capacity to support the design loads. In cases where rain was ruled out as a potential cause, other potential causes of the collapse were evaluated.