Pitched Roof Rafter

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.

Pitched roof rafter.

For example in an equal hip roof with an 8 12 pitch the pitch of the hip rafter would be 8 17. It is the length of this portion of the rafter. Discover the pros and cons to multiple roof designs. The rafter member will be longer.

The pitch and span of your roof will dictate how long of a rafter you ll need use maximum span calculator to help you find your rafter size. Roof pitch is often expressed as a ratio between rise and run in the form of x 12. Roof pitch is simply the slopecreated by the rafter. Common rafters are the most common type of rafter in construction.

Learn the 1 rafter design that will guarantee your roof that is safe and strong for years to come. Once you ve marked the lines use your pencil to draw the diagonal length on the rafter. If you plan to have overhang etc. It can be assessed in two ways either as the angle the rafter makes with the horizontal or the proportion between the rise and the run of the roof.

Tools needed to work out roof rafter lengths. The roof pitch should be specified on your technical drawings for the job along with the sizes of the roof timbers. If you are deciding yourself on the pitch make sure it is suitable for your roof covering. But here it will be different since the hip rafter doesn t lie at 45 degrees to the commons.

If you look at the rafter span chart you ll notice that 2x4s can be used for rafters on spans up to 11. To cut roof rafters start by fixing the stair gauges on your framing square to the dimensions of your pitch. Pitch is the incline of the roof represented as the ratio of rise to the span twice the run. Our roof rafter calculator tools are handy for calculating the number of rafters needed rafter length calculator lineal feet of rafter board feed in ridge and sub facia and the total board feet in the roof.

There are minimum roof pitches many tiles like slates for example must be laid on in order to stay put and not leak. 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. In a hip roof with equal pitches the unit run of a hip or valley rafter is 17 inches for every 12 inches of run in the main roof. For example if the roof rises 4 feet and the span is 16 feet twice the run then the pitch is 4 16 or 1 4.

Rise and run means that a 6 12 pitch roof has 6 of rise vertical for each foot of run horizontal. Note that this is not the actual length of the rafter.