Assume a required single span of 12'-9", dead load of 10 psf and joists spaced 16" on center Table F-2 (see following highlighted tables) shows that one solution is a grade of 2x8 having an Fb value of 1255 would allow a span of 12'-10" which satisfies the ndition. (Note that the rOkaymmended E value to limit deflection would be 1,600,000.)