Raccoons have evolved to adapt to traits that serve their behaviour well, such as climbing trees and gnawing through many types of material to obtain food. If there are some types of metal that raccoons can easily chew through, then it goes without saying that wood is a very easy substance for the animals to chew through. Raccoons will typically scavenge for food due to their size, which makes them not very adept at hunting or fighting.
This behaviour relies upon a set of skills to ensure that they can easily obtain food sources that are concealed or hidden, in addition to barriers blocking attractive spots for habitation. If a structure is made of wood, or plywood more specifically, raccoons frequently rip holes through these structures to find nesting spots. An attic is a perfect home for a raccoon due to the warmth and safe haven offered by the outside elements.
Wood is much easier for raccoons to chew through, which may not be a good sign if your roof is built primarily out of plywood. If you have noticed raccoons chewing through the wood on your roof, or, have found holes in the roof which lead to the attic, this is likely evidence of raccoons. Contact a raccoon removal specialist immediately to both safely remove the raccoons and to repair the damage and raccoon proofing services.