See this is a discussion that needs to occur, the liner works fantastic (depending on type purchased and being properly installed) on a trailer floor made out of plywood (just using generic term). On PT boards, with gaps every 6 inches, why is it better or worse? My .02 is that you can’t use liner on all 6 sides because that would seal the wood, and sealing wood isn’t good. I would say to use maybe a liner on top or paint or stain, then stain/oil the bottom. Better yet, oil the whole enchilada. Oil and water don’t mix, so long as you keep it oiled. The only other option is to decrease the trailer cross members and use the trex that IBS or someone was mentioning. Then you don’t have to worry about wood rotting.
Not entirely focused on you, but just a train of thought. I’m a big fan of oil. I had put down a thick coating on my deck in year one, but it is getting stripped this year and oiled.
do you strain the oil or anything? or just let the gunk settle? I have like 10 gallons from changing the oil on our trucks and some other vehicles at the shop…I actually have like 15 gallons of oil based stain out in the shed somewhere too. Might be a neverending supply