You know, even the best of us get caught in a brain fade. I had at my housienda "mucho porchos" constructed and when my back was turned, the contractor installed finger- jointed "fir".......I mean the good stuff.......when I wasn't lookin'. Rather than make an issue of a small town deal, I mean, I drink coffee with this guy, I let it go. Not a good thing to do. Even tho all this material is under roof, it is going south at leading edges from wind blown snow and rain......and it has been covered with deck paint and primed and coated on all surfaces "prior" to installation per manfr's requirements. Fir is a good material, but from what I understand, and sometimes that is minimal, it has limits as to the lengths you can get, and that may not fit my situation. However, I think I can work it out.
But, during this painful thought process, as I watched my proch decks "rot" I considered my options. I didn't want treated material, just isn't up to my speed. But I looked to other options. I have "existing" conditions cuz it all has to fit under the elaborate french door system leading out to these monster porches so 3/4" material is necessary. I have given thought to "milling" composite/man made materials which will last forever, but they say these products need to stay in their 1x dimension cuz of strength limitations for a standard joist span of 16". So, if I mill it to 3/4", I will have to block under all the material to hold it up (and I am seriously considering it cuz in the long run, it will last for ever without much upkeep).........!
I feel for you. Keep posted and I am sure you will get some help.......maybe me too.