Laminate Floor Pad

North side of house three-season porch enclose insulated floor over
crawl space. Crawl space has a moisture barrier on the dirt. My
primary concern is occasional rain on the floor and the sound this
type of flooring makes. ¾-4-8 bead board is $3.80 per sheet and seems
like a cost effective solution for a pad. It will cost me 1" of
headroom. What other problems will I have? thanks