Can 2x6x12 be used for deck joists?

Yes, 2x6x12 lumber can be used for deck joists, but it may not be the most common choice. Typically, 2x8 or 2x10 lumber is preferred for greater load-bearing capacity and spacing. The suitability also depends on the span between supports and the anticipated load on the deck. Always consult local building codes and guidelines for specific requirements.