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JOIST SPANS <br />The spa'n tables below for wood species end joist size <br />for various house widths are based on the following <br />design assumptions: <br /> <br />1) Design- <br /> <br /> a. 50 psf total load over both clear spans. <br /> <br /> b, 40 psf live load on one span; 20 psf live load on <br /> the other span; lOpsf dead load over both spans, <br /> c, Deflection Is limited to 11360 of the clear span <br /> under live load, <br /> <br /> d. Deflection for two spans in (b.) are averaged <br /> since splices are placed alternately on one side, <br /> then the other, of the center support. <br /> <br />2) Materials- <br /> a. Lumbar joist -- Size, species and grade as noted <br /> in Icad.span tables, surfaced dry or green and <br /> <br /> used at 19% maximum moisture content, except <br /> where noted kiln-dried (KD is surfaced and used <br /> at 15% or less), <br /> b, Plywood splice -- 1/2"-thick APA C-D INT, <br /> c. Splice fasteners -- 10d common nails (no glue <br /> shall be used}. <br /> d, Plywood floor -- per APA® recommendations for <br /> subfloor or combination subfloor, underlayment. <br /> <br />3) Construction- <br /> a, Joists shall be installed so that the splices <br /> occur alternately on one side, then the other, of <br /> the center support. <br /> <br /> b, All interior partitions shall be non-load-bearing, <br /> except over center support. <br /> <br /> c. Center support ahall be at mid.width of the <br /> building. <br /> <br /> d, Subfloor or combination subfloor,underlayment <br /> shall be plywood installed per APA <br /> recommendations, <br /> <br />16" Spacing <br /> <br /> House Width <br /> 22' 24' 26' 28' 30' 32' 34' <br />Joist Lumber Joist Size <br /> <br />Douglas fir-larch NO. 1 <br /> <br /> NO. 2 <br /> NO. 3 <br /> <br />Southern pine <br /> NO. I KD <br /> No, 2 KD <br /> No, 3 KD <br /> <br />Hem.fir <br /> No. 1 <br /> NO. 2 <br /> No, 3 <br /> <br />2x6' 2x6' 2x8 2x8' 2x8" 2x10 2x10 <br />2x6~ 2x8 2x8 2x8' 2x8" 2x10 2x10 <br />2x8 2x8' 2x10 2x10 2x10' 2x12 2x1~ <br /> <br />2x6' 2x6' 2x8 2x8' 2x8' 2x10 2x10 <br />2x6" 2x8 2x8' 2x8' 2x8' 2x10 2xi0 <br />2x8 2x8' 2x10 2x10 2x10 2x12 2x12 <br /> <br />2x8 2x8 2x8 2x8' 2x8' ~xl0 2x10' <br />2x8 2x8 2x8' 2x8' 2x10 2x10 2x10' <br />~xl0 ~xl0 2x10' 2x12 2x12 2x12' <br /> <br />24" Spacing <br /> <br /> House Width <br /> 22' 24' 26' 26' 30' 32' 34' <br /> Joist Lumber Joist Size <br /> <br /> No, 1 <br /> <br /> NO, 3 <br /> <br />Southern pine <br /> <br /> No, I KD <br /> No. 2 KD <br /> No, 3 KB <br /> <br />Hem-fir No, 1 <br /> No. 2 <br /> NO. 3 <br /> <br />2x8 2x8 2x10 2xlO 2x10 2x10' 2x12 <br />2x8 2x8' 2x10 2x10 2x10' 2x10" 2x12 <br />2×10 2x10' ~xl~ 2x1~ 2x12' -- -- <br /> <br />2x8 2x8 2x10 2x10 2x10 2x10' 2x12 <br />2x8 2x8' 2x10 2x10 2x10" 2x10~ 2x12 <br />2x10 2x10 2x12 2x12 2x12' -- -- <br /> <br />2x8 2x10 2x10 2x10 ~x12 ~×12 -- <br />2x8' 2x10 2x10 2x10' 2x12 2x12 -- <br />2x12 2x12 2x12' -- -- -- -- <br /> <br /> <br />