For roofs that won’t experience heavy snow loads, a gable roof can span up to 22′ with 2×4 rafters. For roofs that will experience heavy snow or wind and will span the same distance, use 2×6 rafters. If you have a simple gable shed roof, then using 2×4 rafters makes more sense unless you have a very large shed.
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″ | 16 | 16-10 |
| 24 | 13-9 | |
| 2″ x 10″ | 12 | 24-6 |
| 16 | 21-6 |
What is the maximum span for a 2×4 Rafter?
How far can you span a 2×4 Rafter?
| 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′ | |
How far can you span a 2×6 roof rafter?
How Far Can a 2×6 Rafter Span? 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.
What kind of wood do you use for roof rafters?
Kiln-dried Douglas fir wood presents the number one choice for building a rafter-styled roof in a wood frame house.
How far can a 2×4 span without sagging?
Generally, 2x4s can extend for up to 20 feet, but a number of issues have to be considered. For instance, the 2×4 would not noticeably sag under its weight at 10 feet.
Can I use 2×4 for ceiling joists?
2×4 are suitable for ceiling joists where the LL is like 20 Lbs. If you got a good species with the highest Modulus of Elasticity and Best grade and use like 12″ o.c. – you might get 8” span.
How far can a 2×4 cantilever?
The distance your joists can safely cantilever or overhang a drop beam is determined by the size of the joists, the wood type and grade of the lumber and the spacing between joists. Many building departments limit joist cantilevers to 24″ maximum.
How far can a 2×4 purlin span?
2×4 purlins may also be nailed on top of the rafters with one 60-d nail or attached with metal clips at each rafter. Rafters may be spaced up to twelve feet, dependent on purlin size, when purlins are turned edgewise.
How much weight can a 2×4 joist support?
If there is no strong wind, a 2×4 measuring at least 8 feet can support at least 1,000 pounds vertically.
How long can a 2×6 span without support?
How far can a 2×6 Rafter span without support? The table states that 2 X 6 rafters spaced 16 inches on center (o.c) can span a maximum distance of 13 feet 5 inches.
Are two 2×6 stronger than a 2×8?
In bending, a joist composed of two 2×6’s (true dimension 1.5 inches x 5.5 inches) are slightly stronger than a single 2×8 true dimensions 1.5 inches by 7.25 inches.
How far can a 2×6 span without support deck?
Decking boards span from joist to joist. If you use 5/4 decking, joists must be no farther apart than 16 inches. Decking made of 2x4s or 2x6s can span up to 24 inches.
Can I use pressure treated wood for roof rafters?
As long as the rafters are not directly exposed to the elements, no need to be treated. … Treated is generally for ground contact or exposed to the elements or high humidity areas.
What is the maximum span for a 2×6 ceiling joist?
For example, the highlighted cell (below) shows that a 2″ x 6″ Southern Yellow Pine joist, with a grade of #2, and spaced 24″ apart can have a maximum span of 10 feet – 0 inches (10-0), if you are designing your structure to support a plaster ceiling.
Which is better rafters or trusses?
Once in place, rafters use up more wood, so they weigh more, but trusses are stronger because they are more efficient and have the capacity to produce maximum strength using fewer materials in the end.