Crazing is characterized as hundreds of very small cracks (sometimes undetectable by eye) occurring in complex spider-web shapes. Again, multiple causes exist that create these phenomena. Chemical attack at the top or bottom surface is the most common cause. In fact, the single most common cause is attack from the back surface by un-reacted styrene, which is an ingredient in FRP.

This crazing is somewhat common around the rim of a spa due to the manufacturing process. Surfaces that exhibit crazing are more difficult to repair.