Lumber Roof Spans

Spaced sheathing or 1x boards may be reduced slightly.

Lumber roof spans.

For the initial calculation f can be estimated at 1 000. The lengths and sizes of joists vary depending on the species and quality of the lumber used. Simplified span tables for southern pine lumber and glued laminated timber glulam headers beams and girders. 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.

Also available for the android os. 1 ft 0 3048 m. View size selection tables. The total load is 4 000 pounds.

2 are indicated below. 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. The above spans are based on american softwood lumber standard sizes.

These sizes are as follows. Live load 20 lbs ft 2 956 n m 2. In the example the beam spans the 10 foot width of the roof. Douglas fir maximum horizontal roof rafter span for lumber grade selected structural and no.

Dead load weight of structure and fixed loads 15 lbs ft 2. Use these two tables for roof rafters with a slope greater than 3 in 12. Trusses must be designed for any special loading such as concentrated loads from hanging partitions or air conditioning units and snow loads caused by driftingnearparapetorslide offfromhigherroofs. Live load is weight of furniture wind snow and more.

View allowable load tables. 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. 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. 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.

Span calculator for wood joists and rafters also available for the android os. 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. Allowable spans for 2x4 top chord trusses using sheathing other than plywood e g.

Tabulated spans apply to surfaced s4s lumber having dimensions which conform to the american softwood lumber standard ps 20 10.