Roof Rafter Dimensions

See rafter run to outer wall calculator below.

Roof rafter dimensions.

Are there any brittle finishes e g. Plasterboard on the underside of the rafter. Gable walls need to be strapped to the roof at the maximum 2m centres using 30 x 5m galvanised mild steel straps. Rafter is the beam supporting the building.

Pitch is the incline of the roof represented as the ratio of rise to the span twice the run. Roof rise this should be calculated from the base of the roof to the highest point of the roof gable the peak. Next set the framing square on top of the rafter beam and use a pencil to trace the outside edge of the framing square s tongue. 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.

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. Rise and run means that a 6 12 pitch roof has 6 of rise vertical for each foot of run horizontal. Imposed loads roof snow load and short term point load. It is the length of this portion of the rafter.

This is the distance between rafter centres. Print full scale rafter cut templates and birdsmouth templates fold template over rafter to mark or cut through. There are several variables to consider when determining the proper rafter size. Usually 400 450 or 600mm but any value can be used up to 610mm max.

To cut roof rafters start by fixing the stair gauges on your framing square to the dimensions of your pitch. The rafter member will be longer. Here the number is 941 86 inches. 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.

This diagram illustrates the typical arrangement of a rafter and purlin roof and shows the dimensions referred to in the tables above. This sizing guide for roof rafters will help determine what you need for your small project. A useful shed roof rafter calculator to calculate the rafter length for the given dimensions of the roof of the building or a structure. If you plan to have overhang etc.

Once you ve marked the lines use your pencil to draw the diagonal length on the rafter. Half building width minus 1 2 ridge thickness. Here the number is 1166 66 inches. Weather you re building a shed roof or adding a dormer to your second story it is important to choose the proper size rafter.

Find its length with our online rafter length calculator.