Fiber Lok is thick and dried out looking, Can it still be used? Monica P. March 03, 2020 14:45 No, the Product has a 6-month shelf life and can dry out over time or if partial container is left unused for too long. Related articles What di I do if my Fiber Lok rug backing is too thick to spread? How long does it take for Fiber Lok rug backing to dry? Comments 0 comments Article is closed for comments.