Roof Rafter Sizes

Rafter slope min 15 max 45 degrees.

Roof rafter sizes.

This is the distance between rafter centres. Input the rafter span on the flat eave overhang and pitch of the roof. Clear span on plan. The full version allows any size.

Here the number is 941 86 inches. Input the rafter span on the flat eave overhang and pitch of the roof. If your project had a rafter length of 8 or less a safe and strong method is to use 2x8 framed 16 on center. Here the number is 1166 66 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. 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. It is always better to have a large rafter rather than be concerned with a sagging roof. This calculator is to be used as an estimating tool only.

Rafter stock size calculator. This calculator is to be used as an estimating tool only. Roof rise this should be calculated from the base of the roof to the highest point of the roof gable the peak.