The 96 in. Veranda HP Reversible Cellular PVC Sheet is a durable alternative to wood products. It is engineered to resist expansion and contraction and has a hard surface that protects against dents and
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They cut it to my specifications for free, and I simply glued it together... I'll definitely do it again.
They make it in 1/2" also, but I liked the solidity of the 3/4" trim board.