Thanks, I'll search for that plastic board, also I think the problem is undermount ang sink ko which rests on the plywood so baka bumigay sa bigat. I'm considering a thicker plywood, a thicker stone and a top mount sink na. I'll visit a stone store tomorrow.

Edit: PVC board ba? Versaply nakita ko, more of for form works ang recommendation nila, baka iba pa ito sa phenolic.