When a commercial livestock owner in Ohio retrofitted his 5,000-square-foot pole barn, he initially relied on FRP sheets over OSB backer boards. Within three years, seasonal humidity and daily pressure washdowns caused the wooden backing to rot, swelling the seams and forcing a complete wall tear-out. The absolute best alternative to FRP for pole barn interiors is PVC wall panels. Switching to PVC pole barn interior wall covering permanently solves the moisture, structural, and installation drawbacks inherent to traditional FRP barn cladding.