Allowable Stresses in Dimensional Lumber

Joists: Floor and Roof 2'' x 8''

Species: D, F South
Grade: No 1
E: 1,300,000 psi

F'b (Floor) = Fb x Cf x Cr x Cfu = 1277 psi
F'b (Roof) = Fb x Cf x Cr x Cfu = 1064 psi
F'v = Fv = 180

Beams: 4'' x 8''

Species: D, F South
Grade: S, S
E: 1,400,000

F'b = Fb x Cf x Cfu = 1843 psi
F'v = Fv = 180

Headers: 2'' x10''


Species: D, F South
Grade: No 1
E : 1,300,000 psi

F'b = Fb x Cf x Cfu = 1221 psi
F'v = Fv = 180

Studs: 2'' x 6''

Species: D, F South
Grade: Stud
E : 1,100,000 psi

F'b = Fb x Cf x Cr = 1009 psi
F'c = Fc = 830 psi

Posts - Columns: 4'' x 4''

Species: D, F South
Grade: No 1
E : 1,300,000 psi

F'b = Fb x Cf = 925 psi
F'c = Fc = 1450 psi