1 in 25 4 mm.
Lumber roof spans.
Tabulated spans apply to surfaced s4s lumber having dimensions which conform to the american softwood lumber standard ps 20 10.
Use these two tables for roof rafters with a slope greater than 3 in 12.
Live load 20 lbs ft 2 956 n m 2.
The above spans are based on american softwood lumber standard sizes.
Also available for the android os.
The total load is 4 000 pounds.
For the initial calculation f can be estimated at 1 000.
Simplified span tables for southern pine lumber and glued laminated timber glulam headers beams and girders.
Douglas fir maximum horizontal roof rafter span for lumber grade selected structural and no.
For additional species of lumber check out the rafter span calculator from the american wood council website.
The spans in this table are based on a maximum supported rafter span of 16 feet where the supported span is the total horizontal distance spanned by the roof rafters divided in half not the diagonal distance or the length of the rafter.
1 psf lb f ft 2 47 88 n m 2.
Allowable spans for 2x4 top chord trusses using sheathing other than plywood e g.
The lengths and sizes of joists vary depending on the species and quality of the lumber used.
Live load is weight of furniture wind snow and more.
In the example the beam spans the 10 foot width of the roof.
These easy to use tables were compiled by the southern forest products association sfpa as a service to design build professionals and other southern pine users.
Dead load weight of structure and fixed loads 15 lbs ft 2.
Spaced sheathing or 1x boards may be reduced slightly.
These sizes are as follows.
So this table could accommodate a house with a total rafter span or house width of 32 feet.
Span calculator for wood joists and rafters also available for the android os.
F stands for the beam s fiber strength in bending which depends on the species of wood.
For example you can span a 1 grade no knots southern yellow pine a greater distance than a 2 grade with knots southern yellow pine.
Nominal actual surfaced size dry size 2 x 4 1 1 2 x 3 1 2 2 x 6 1 1 2 x 5 1 2 2 x 8 1 1 2 x 7 1 4 2 x 10 1 1 2 x 9 1 4 2 x 12 1 1 2 x 11 1 4 4.
View allowable load tables.
2 are indicated below.
View size selection tables.
Using table f 2 figure 3 check each lumber size to see if a 16 inch spacing will permit a span of 15 feet 1 inch.
