We will need to be replacing the existing 2 X 4 deck boards on several
smallish decks (6' X 12' +/-). Rain water/freezing/mold/mildew are not a
factor, as this is the warmest, sunniest place in the nation. The sun has
destroyed the original decking, and several galvanized nails (which usually
hold and outlast the wood) are "floating."

I'm a PNWer, so I'm quite familiar with how to handle this in a cool, wet
climate, but I'm still learning about the wreckage hot sunshine and low
humidity can cause. I'm not sure if pressure, or otherwise treated lumber
will gain us any advantage in this situation. Trex and the like are simply
too expensive for this application, so we're looking at wood, unless there
is a cheaper alternative in synthetic materials.

We're building stucco enclosures to replace the existing wood handrails, to
afford some privacy and upgrade the look of these decks. Sealing the deck
floors, building scuppers or drain pipe systems is not an option, so the
decks must have slats to allow for the rare occasions when it does rain
(monsoons). My thinking is that it may be more cost effective, in the long
run, to use 2 X 6, 8, or 10 material, which might last longer and be less
susceptible to warping/cracking, properly attached, of course.

OK, let me have it.

Thanks