Not being sure where this should be asked, I'm putting it in a couple of places.
My son-in-law is building a playset outdoors for his children. He is using left-over wood from his attic flooring (I think it's pressed wood -- has wood chips showing) for the deck (about 4 feet off the ground) of the playset. Will this be safe left unfinished? It's about 4ftX4ft with the only bracing being around the edges. It will currently hold his weight -- over 200 pounds, so he says it will be fine for the little guys.
I thought that type of wood was meant to be covered up, protected from the elements, but the older I get, the less sure I am of anything, so I would like some advice from those who use this product, or have built something like this for their children. Thank you so much.