I contracted out rebuilding our staircase from a ground-level patio up to our deck because after 20 years, the untreated wood that was used by the original home builder began to rot. I don't feel as if my contractor did a lot of planning and just started to build. Long story shorter, he either cut the ends of the pressure-treated stringers where they attach to the deck (rim joist) over two inches too short, or really needed 3x12s slightly longer than 16' but didn't realize that initially and is trying to make do. To remedy this mistake, he is using leftover blocks of pressure-treated wood to extend the ends of the stringers to flush up against the deck/rim joist. He's not even using the logically-sized blocks.

Check out the picture:

I am not a carpenter, and don't have much experience with construction at all, but seeing that this a staircase and it rises about 10' high, it seems like this would be a place where you wouldn't want to do any type of "rigging" at all. So, I have a few questions:

1. Is it acceptable and to code (I'm in Colorado) to use extra blocks of wood to extend one end of a stringer so strap-ties can be attached and the stringer can then be attached to the deck, or should the stringer be a continuous piece of pressure-treated lumber?
2. If it is acceptable, do you feel the pieces/blocks of wood he is using in the picture above are an acceptable size and shape?
3. Can you buy 3x12 pressure treated lumber longer than 16', like 18' or 20', etc.?

In my opinion, if the stringers were planned using basic geometry/math, or some type of software (CAD) properly, he would've known that we needed longer stringers than 10' and could have avoided all of this. Please let me know what you think, especially if you are a carpenter/staircase builder.

Thanks,

Dave