Roof Rafter Span Sizes

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.

Roof rafter span sizes.

Roof rise this should be calculated from the base of the roof to the highest point of the roof gable the peak. Live load 20 lbs ft 2 956 n m 2. Input the rafter span on the flat eave overhang and pitch of the roof. Here the number is 1166 66 inches.

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. Here the number is 941 86 inches. Rafter run outer wall this should be measured starting from the center of the roof span and then extending to the very edge of the exterior wall. Click the button to calculate the stock size needed for this job.

Click the button to calculate the stock size needed for this job. Usually 400 450 or 600mm but any value can be used up to 610mm max. There are several variables to consider when determining the proper rafter size. Input the rafter span on the flat eave overhang and pitch of the roof.

This is the distance between rafter centres. 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. This calculator is to be used as an estimating tool only.

1 ft 0 3048 m. 1 in 25 4 mm. Publications calculators software building codes fire safety span tables decks weights and measurement codes standards calculators software. This sizing guide for roof rafters will help determine what you need for your small project.

This calculator is to be used as an estimating tool only. Rafter stock size calculator. Douglas fir maximum horizontal roof rafter span for lumber grade selected structural and no. Live load is weight of furniture wind snow and more.

1 psf lb f ft 2 47 88 n m 2. For heavy roofs or in areas with substantial snowfall or winds call your local building department for code requirements.