How much subfloor do I need over a crawlspace for some really heavy machines? The joists are sized correctly but I worry I need thicker floor. The builder put down 3/4" Advantech OSB which seems pretty stout, but a 1500 lb machine on it might make me reconsider.

Right now I'm leaning towards putting down SPC vinyl due to the impact and scratch resistance, though there's a small chance I could wind up with solid oak.

If I go vinyl, should I lay down another layer of OSB or anything to stiffen things up?