Lumber Roof Spans

F stands for the beam s fiber strength in bending which depends on the species of wood.

Lumber roof spans.

View allowable load tables. 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. 1 psf lb f ft 2 47 88 n m 2. So this table could accommodate a house with a total rafter span or house width of 32 feet.

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. Also available for the android os. The lengths and sizes of joists vary depending on the species and quality of the lumber used. 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.

The total load is 4 000 pounds. The above spans are based on american softwood lumber standard sizes. Spaced sheathing or 1x boards may be reduced slightly. View size selection tables.

Tabulated spans apply to surfaced s4s lumber having dimensions which conform to the american softwood lumber standard ps 20 10. 1 in 25 4 mm. 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. Allowable spans for 2x4 top chord trusses using sheathing other than plywood e g.

Live load is weight of furniture wind snow and more. In the example the beam spans the 10 foot width of the roof. 1 ft 0 3048 m. Simplified span tables for southern pine lumber and glued laminated timber glulam headers beams and girders.

Start with the 16 0 line in the spacing column at the left of the table then go to the right until you reach an appropriate span at least 15 feet 1 inch in this case. 2 are indicated below. Dead load weight of structure and fixed loads 15 lbs ft 2. These sizes are as follows.

Use these two tables for roof rafters with a slope greater than 3 in 12. For additional species of lumber check out the rafter span calculator from the american wood council website. Douglas fir maximum horizontal roof rafter span for lumber grade selected structural and no. Span calculator for wood joists and rafters also available for the android os.

Live load 20 lbs ft 2 956 n m 2.