We just added a fully enclosed hay storage area onto our barn. The new area has a concrete floor and we're trying to determine the best barrier to use between the hay and the concrete. We live in the high desert of southwest Colorado which is a very dry climate for most of the year. We've been storing our hay in some sheds and part of the barn directly on the OSB plywood floors which are elevated at least 6 inches above the ground. We've never had any hay we've stored get moldy.
We're considering rubber stall mats, perforated rubber wash rack or restaurant mats, hay tarps, pond liner, plywood, and as very last resort pallets...trying to avoid using pallets.
We get our hay from the same grower each year. It's cured when we get it delivered and he tests the moisture level when he bales it. It's always been high quality, never a bad or moldy bale.
Any advice on the best barrier is appreciated, especially from those in the same or similar dry climate.