Lean To Roof Joist Spacing

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.

Lean to roof joist spacing. 2 are indicated below. Live load is weight of furniture wind snow and more. A roof joist is always spaced no more than 16 inches apart from another roof joist. In general the maximum span for a 4 by 6 beam is 6 feet between 4 by 4 posts.

A 4 by 10 can usually span up to 12 feet between posts. If you move up to 4 by 8 you re usually allowed to span up to 10 feet between posts. Enter this measurement into the calculator and select a roof pitch and the length of the rafter will automatically returned along with the rise. 1 psf lb f ft 2 47 88 n m 2.

If the roof is not completely square you can decrease the space between joists but never increase the space. Keep in mind that these figures depend on the size and spacing of joists and the overall structural loads. Dead load weight of structure and fixed loads 15 lbs ft 2. Live load psf dead load psf span calculator for wood joists and rafters available for the iphone.

In other words you would space a roof joist 15 inches apart from another roof joist but never 17 inches apart. Span calculator for wood joists and rafters also available for the. Spacing in exterior exposure.