Rafter Lengths And Roof Construction

Rise and run means that a 6 12 pitch roof has 6 of rise vertical for each foot of run horizontal.

Rafter lengths and roof construction.

Roof rise this should be calculated from the base of the roof to the highest point of the roof gable the peak. Here the number is 1166 66 inches. Half building width minus 1 2 ridge thickness. Pitch is the incline of the roof represented as the ratio of rise to the span twice the run.

Determine the camber along the timbers length. Rafters are commonly spaced about 24 inches 61 cm apart. The run of the rafter. The dotted line is how the rafter length measurement is used measure from the point at the top down the length and plumb a line there.

Lengths of roofing timber almost always bow slightly. Use our online rafter length calculator to quickly compute the length of the shed roof rafter by entering the measurements of overhead length of roof span pitch or angle. The rafter member will be longer. Allow for ridge thickness when determining rafter run to outer wall.

Print full scale rafter cut templates and birdsmouth templates fold template over rafter to mark or cut through. Here the number is 941 86 inches. Before you can mark the rafter lengths and layout check the camber of the timber. If you plan to have overhang etc.

Note that this is not the actual length of the rafter. Calculate the length of a rafter from the roof slope ratio of inches per foot and a building width measurement. Includes result for hip valley factor slope factor and the roof slope in degrees. The results are automatically fired.

The length of the rafter. See rafter run to outer wall calculator below. 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. There could be many rafters supporting a roof.

It is the length of this portion of the rafter. 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. The number of rafters needed will be determined by the length of your 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.

Height of the scaffold. The rise of the rafter. Calculate the length of common rafters with this free and easy online tool by entering a dimension for the roof width selecting a pitch for the roof and the thickness of the ridge. If you add an eaves overhang dimension then the amount the rafter sticks passed the wall will be added to the rafter length.

This calculator helps you make the rafters of the suitable sizes required for your roofing.