Roof Rafter Span Definition

1 psf lb f ft 2 47 88 n m 2.

Roof rafter span definition.

1 ft 0 3048 m. Hip rafter angle rafter. In our sketch the rafter span is referred to as the rafter line length. This means that each rafter is built on the job site using dimensional lumber.

The un supported length of the rafter along its slope the diagonal or hypotenuse of a right triangle. Rafter span tables use these tables to determine lengths sizes and spacing of rafters based on a variety of factors such as species load grade spacing and pitch. The span would be 11 5 3 4. Span calculator for wood joists and rafters also available for the android os.

Definition of rafter run. Rather the span is based on the rafter s horizontal projection. Rafter spans for southern yellow pine douglas fir and eastern spruce. Also available for the android os.

The longest rafter on the side of a hip roof in line with the ridge. 2 are indicated below. Normally a roof span is the same as the building width between the outer edges of the wall top plates. This is the horizontal distance from the inside surface of the supporting wall to the inside surface of the ridge board.

The rafter in the corners of a hip roof. In our sketch above the rafter run is shown as run under the left half of the roof. Building with them is known as stick framing. So consider a simple gable roof on a 24 foot wide ranch framed with 2x6 exterior walls and a 1 1 2 ridge.

Dead load weight of structure and fixed loads 15 lbs ft 2. Use this table to determine the maximum lengths of ceiling joists based on species of lumber joist spacing and joist size. The horizontal or level distance covered by the rafter the bottom chord or base of a right triangle. Definition of rafter span.

The upper rafters in a curb kerb gambrel mansard roof roof. Definition of roof span. 1 the span of a rafter is not based on the measurement along its length. Douglas fir maximum horizontal roof rafter span for lumber grade selected structural and no.

This is the horizontal distance from the inside surface of the supporting wall to the inside surface of the ridge board. Rafters are the traditional means of framing a roof. Rafter spans can be extended slightly beyond what the rafter tables suggest when there is a cantelever extending beyond the supporting wall. Visit the roof framing page for more information on cutting roof rafters and visit the roof pitch calculator for determining rafter lengths based on rise and run.

Live load 20 lbs ft 2 956 n m 2. Rather the span is based on the rafter s horizontal projection. The foot of a hip rafter lands on a dragon beam. Every piece is measured cut and fastened together to form the rafter.