I replaced my subfloor in my house leveling the floors for hardwood this winter. Researched for the best sub-flooring and found Advantech.
It's a resin impregnated osb-type flooring. But don't think OSB. It's 40% stronger/stiffer than plywood, extremely dense, at 75# per 4x8 sheet, and extremely resistent to warping. Best part is that the high resin content makes it extremely water resistant. Extremely flat and stable. After leveling the joists and installing 3/4 Advantech, if we every Build another house, that'll be my flooring.
A contractor I know said he has scraps that have been in the weather outside his shop for years that look like new. I've got some scaps that have been outside for 3 months and I wouldn't hesitate to use them for anything.
It's sanded both sides, so very smooth for a glue edge and easy to cut. Same cost as good plywood. Would take screws much better than MDF. Makes great Speaker baffles also
Yeah, give the Advantech a look see. I was sold on it.
For the floor, I used the PL premium construction adhesive. That stuff is amazing too once it dries, the joint isn't coming apart. You can split the wood around it, but the bond isn't breaking. Probably overkill, but I've got 5 large tubes left, so I'll probably try some for a box.
Advantech is very smooth. We walked on it for about a month while getting the hardwood down on bare feet (Kentucky
) and you can slide on it. It's not quite as smooth as MDF, but much smoother than osb.