Have you considered using the space as storage? I'd use the treliss with a door of some sort. Bicycles, wagons, kids toys. They're all things that need to be pput away and would be easy for the kids to use

shirley

What to put under your deck? How about a sign that reads "do not install Trex above this sign". Sorry, couldn't resist with all the bad press about that composite.
Jeff

See how good I was being Jeff,I knew if I waited long enough I woudent have to mention the T=junk thing.

I do a lot of solid skirting with cross vintalation installed, square lattice on a close pattern like 2'' looks nice. J

Joyce,

We are just finishing a deck that has the floor 3 ft above the ground and will be doing the lattice approach for the same reasons.

I forgot to add that we put down weed stop fabric covered with a 3" depth of 2" stone under the entire deck.