Rafter Lengths And Roof Construction

Lengths of roofing timber almost always bow slightly.

Rafter lengths and roof construction.

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. Half building width minus 1 2 ridge thickness. Here the number is 1166 66 inches. See rafter run to outer wall calculator below.

The rafter member will be longer. Rafter is a sloping beam usually wood that supports a pitched roof. Pitch is the incline of the roof represented as the ratio of rise to the span twice the run. All roof rafters should be identical so follow the same steps to measure the plumb cut tail cut and birdsmouth cut.

The number of rafters needed will be determined by the length of your roof. Rafters are commonly spaced about 24 inches 61 cm apart. Includes result for hip valley factor slope factor and the roof slope in degrees. 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.

Here the number is 941 86 inches. Note that this is not the actual length of the rafter. The rise of the rafter. There could be many rafters supporting a roof.

Print full scale rafter cut templates and birdsmouth templates fold template over rafter to mark or cut through. Height of the scaffold. The results are automatically fired. The length of the rafter.

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. Before you can mark the rafter lengths and layout check the camber of the timber. If you plan to have overhang etc. This calculator helps you make the rafters of the suitable sizes required for your roofing.

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. Determine the camber along the timbers length. It is the length of this portion of the rafter. Allow for ridge thickness when determining rafter run to outer wall.

If you add an eaves overhang dimension then the amount the rafter sticks passed the wall will be added to the rafter length. Rise and run means that a 6 12 pitch roof has 6 of rise vertical for each foot of run horizontal. 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. The run of the rafter.

Calculate the length of a rafter from the roof slope ratio of inches per foot and a building width measurement.