We have a raised concrete patio that is 15 x 15 feet. It is old and gets dirty from a tree that drops seed pods, etc. But... it is in pretty good shape. What can we do to update this patio? Can patio stones be place on top, other paver type of materials, or even wood-like products to update it? We don't want to spend a fortune and do no want to demolish the deck. The step down to it is deep so we have room to top it with some product.

How high is it raised and what is beneath it supporting it?

I would build a low-lying platform deck using composite decking. That's what I'm doing at my house. I'll be building one and the top will only be about 8-10 inches high. This way I won't need a railing.

If you go this route, dig down at the edge of your patio. If the slab is thick enough you might be able to set up the joists right on top... otherwise you'll have to dig down below the frost line.