How far can you span a 2x6 roof rafter?

Max. Live Load 20 lbs/ft2 (956 N/m2) Maximum Span (ft – in) Nominal Size (inches) Rafter Spacing, Center to Center, OC (inches) Lumber Grade 2 x 6 12 16′ – 4” 16 14′ – 11” 24 13′ Click to see full answer. Also know, how far can you span a 2×8 roof rafter?In general terms, joists spaced 16 inches on center can span 1.5 times in feet their depth in inches. A 2×8 up to 12 feet; 2×10 to 15 feet and 2×12 to 18 feet. The larger the deck, the larger the joists.Subsequently, question is, how long can a 2×4 Rafter span? ?? If the walls are 2×4 then the clear span from inside wall to inside wall is 8′-5″. It really depends on the grade of wood but the most conservative in the table is eastern spruce at 8′-7″. Thereof, what size should roof rafters be? Use these two tables for roof rafters with a slope of 3″ in 12″ or less. Nominal Size Spaced (o.c.) Species / Grade ( 20# Live Load – No Finished Ceiling) 2″ x 8″ 24 16-8 2″ x 10″ 12 27-6 16 24-8 24 21-3 What size lumber can span 20 feet? Re: 20 foot clearspan beam size In that case, you need something like a 12-16″ GLULAM or LVL to span the 20′ and can use simple 2×8-10 dimensional lumber 16″OC as floor joists.