We recently built a house that had a 12ft wide and 2 foot deep concrete detention area in the very back of our property that belonged to the HOA. This was an established neighborhood that had 'established' that the homeowner took care of it by cleaning etc. We decided to run 2x8 joists secured with anchor bolts to detention wing walls and then overlaid 5/4 deck boards (treated pine). It wasn't the kind of job you'd do on your backyard deck but it keeps the leaves out and the kids! One thing we did was make the center 6 feet removable by making panels that lay down and can be removed.

So enough details.. what is going to be the best method to protect the wood from warping, splintering etc considering its not our 'back yard deck' and we are not as concerned with asthetics. I want what will seal the deck the best, period. Also, how long can I expect this thing to last if I keep it sealed and repeat every couple years?

All the best.