INSTRUCTORS NOTE: Refer students to joist span chart in outline to clarify. MAXIMUM SPANS Southern Selected Yellow White Species Yellow Pine Douglas Yellow Pine Douglas Pine Fir Pine Fir Grades NO. 1 NO. 2 NO. 3 NO. 1 NO. 2 NO. 3 Size Spacing 30# Live Load 40# Live Load O.C. 12 12-6 11-3 12-0 11-4 10-3 10-11 2 x 16 11-4 10-10 10-11 10-4 9-4 9-11 6 24 9-11 8-8 9-7 9-0 7-9 8-8 12 16-6 14-11 15-10 15-0 13-6 14-5 2 x 16 15-0 13-6 14-5 13-7 12-3 13-1 8 24 13-1 11-6 12-7 11-11 10-3 11-3 12 21-0 19-0 20-3 19-1 17-3 18-5 2 x 16 19-1 17-3 18-5 17-4 15-8 16-9 10 24 16-8 14-7 16-1 15-2 13-1 14-6 12 25-7 23-1 24-8 23-3 21-0 22-5 2 x 16 23-3 21-0 22-5 21-1 19-1 20-4 12 24 20-3 17-9 19-7 18-5 15-11 17-6 (On SLIDE #99) (h) Bridging stiffens the joists and prevents them from swaying. One line of bridging is required between floor joists when the joists are no more than 8' long, and two lines are required for joists 16 feet long. (i) Plywood sheathing, 5/8" or 3/4”, is used as to tie all structural members together and provide a smooth surface for finish floors. The joist spacing should not exceed 16" O.C. when a finish floor will be laid parallel to the joists. (j) Plywood sub-flooring must be laid perpendicular to the floor joists to prevent low spots (sagging) in the floor.
INSTRUCTORS NOTE: Refer students to joist span chart in outline to clarify. MAXIMUM SPANS Selected Species Yellow Pine Southern Yellow Pine Douglas Fir Yellow Pine White Pine Douglas Fir Grades NO. 1 NO. 2 NO. 3 NO. 1 NO. 2 NO. 3 Size Spacing O.C. 30# Live Load 40# Live Load 2 x 6 12 16 24 12-6 11-4 9-11 11-3 10-10 8-8 12-0 10-11 9-7 11-4 10-4 9-0 10-3 9-4 7-9 10-11 9-11 8-8 2 x 8 12 16 24 16-6 15-0 13-1 14-11 13-6 11-6 15-10 14-5 12-7 15-0 13-7 11-11 13-6 12-3 10-3 14-5 13-1 11-3 2 x 10 12 16 24 21-0 19-1 16-8 19-0 17-3 14-7 20-3 18-5 16-1 19-1 17-4 15-2 17-3 15-8 13-1 18-5 16-9 14-6 2 x 12 12 16 24 25-7 23-3 20-3 23-1 21-0 17-9 24-8 22-5 19-7 23-3 21-1 18-5 21-0 19-1 15-11 22-5 20-4 17-6 (On SLIDE #99) (h) Bridging stiffens the joists and prevents them from swaying. One line of bridging is required between floor joists when the joists are no more than 8' long, and two lines are required for joists 16 feet long. (i) Plywood sheathing, 5/8" or 3/4”, is used as to tie all structural members together and provide a smooth surface for finish floors. The joist spacing should not exceed 16" O.C. when a finish floor will be laid parallel to the joists. (j) Plywood sub-flooring must be laid perpendicular to the floor joists to prevent low spots (sagging) in the floor.