How far can a 2X10 rafter span without support?
A 2×10 beam – made up of two 2x10s nailed together – can span up to 11′ without support beneath a deck that is 4′ wide. For a more normal-sized deck, the same beam can span 8′, supporting a deck that is 8′ wide. You can also triple a 2×10 beam.
Table of Contents
How far can a 2X6 rafter span without support?
A 2×6 rafter can span 14 feet 8 inches when spaced 16 inches apart with No. 1-grade southern pine lumber on a roof with a 3/12 slope or less with a maximum live load of 20 pounds per square foot and a dead load of 15 psf.
How far can a 2X8 rafter span without support?
How far can a 2×8 rafter span without support. Maximum allowable span for a 2×8 rafter:- the maximum allowable span for 2×8 rafter is 21 feet 7 inches when spaced 12 inches apart from centre, 19 feet 6 inches at 16″ OC & 18 feet 6 inches at 24″ OC with best quality No.
How far can a 3X8 rafter span?
Dimensional Lumber Deck Beam Span Chart
| Joist Spans | ||
|---|---|---|
| Douglas Fir-Larch, Hem-Fir, Spruce-Pine-Fir, Redwood, Cedars, Ponderosa Pine, Red Pine | 3X6 OR 2-2X6 | 4′-5″ |
| 3X8 OR 2-2X8 | 5′-8″ | |
| 3X10 OR 2-2X10 | 7′-0″ | |
| 3X12 OR 2-2X12 | 8′-2″ |
How far can you span a 2×12 rafter?
Max. Live Load 60 lbs/ft2 (2873 N/m2)
| Maximum Span (ft – in) | ||
|---|---|---|
| Nominal Size (inches) | Joist Spacing Center to Center, OC (inches) | Lumber Grade |
| 2 x 12 | 12 | 18′ |
| 16 | 15′ – 7” | |
| 24 | 12′ – 9” |
How far can you span a 2×8 for a roof?
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 8 | 12 | 18′ – 8” |
| 16 | 16′ – 2” | |
| 24 | 13′ – 2” |
What size beam do you need for a 20 foot span?
Wood beam size for 20 feet span:- as per general thumb rule and guidelines, for a 20 foot span, you will need atleast 4-2×16 or 8×16 size of wood beam. Thus, a 4 nailed 2×16 or 4-2×16 or 8×16 wood beam can allow to span 20 feet.
