Safe Spans For No 1 Roof Rafters

For heavy roofs or in areas with substantial snowfall or winds call your local building department for code requirements.

Safe spans for no 1 roof rafters.

For example 2 by 6 rafters made from select structural grade douglas fir that are required to support a live load of 20 pounds per square inch can have a maximum horizontal span of 11 feet 4 inches. So if your house is 26 feet wide and the roof ridge beam is centered on the house you will need a rafter that can span 13 feet. Span calculator for wood joists and rafters available for the iphone. Decreasing the distance between rafters to 12 inches however increases the maximum span to 14 feet 4 inches.

Let s use this example and find a size of rafter that will work. 2 are indicated below. For example in the rafter span table below the highlighted cell in the 40 live load table indicates that 2 x 8 southern yellow pine joists that have a grade of 2 that are spaced 24 apart can have a maximum span of 10 feet 3 inches 10 3 if designing for a live load of 40 lbs ft 2. Span calculator for wood joists and rafters also available for the android os.

Maximum floor joist span no. The 1 grade material is more expensive than the 2 grade but if you can use fewer or smaller 1 grade joists or rafters in your design you may actually save money. 1 ft 0 3048 m. Contact a building control officerfor advice.

Given in the table. The maximum spans in the table above are for the horizontal distance the rafter can span not the diagonal distance or actual length of the rafter. The tables below give maximum spans for rafters and beams. Maximum clear span of rafters in metres for roof pitches of between 15 and 45 degrees roof pitch between 15 and 22 5 degrees with rafter spacing.

Maximum rafter spans for a patio roof in areas with mild climates patio roofs are generally designed for loads of 30 psf pounds per square foot. This type is used to determine the length of the common valley hip and jack rafters and the angles at which they. Live load is weight of furniture wind snow and more. Dead load weight of structure and fixed loads 15 lbs ft 2.

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. Douglas fir maximum horizontal roof rafter span for lumber grade selected structural and no. 2 grade of douglas fir and maximum span floor joists imperial units nails and spikes withdrawal force allowable withdrawal load for nail and spikes softwood and hardwood structural strength classes strength classes bending stress and mean density of hardwood and softwood. 1 psf lb f ft 2 47 88 n m 2.