I would not recommend it. This is heat treated and dried, not pressure treated
Please consult your local building codes to ensure adherence to specs.
Probably. Had some knots and bark. I know there are some restrictions.
Bill -- sorry HD does carry the Dried Spruce Pin Fir in the 16" and larger -- you could glue up boards to meet your requirements.
Only if you have a mill close that will sell it to you.
8', 10' & 12' -- It is the width that is different
Untreated. Not good for garden
Usually it is #2 but just look for a piece that is fairly straight and has minimal knots so it fits in with the rest.
Yes, but you'll probably end up paying more for the cutting then for a single board. IF you're lucky enough to find a straight one !