How To Figure Rafter Lengths For Roof

Step 4 add the measurement for the overhang the eaves on the outside wall to the result obtained in the rafter guide to determine the overall rafter length.

How to figure rafter lengths for roof.

Given here are the formulae to calculate the length of a shed roof rafter to make your roofings stronger and look beautiful. Rise and run means that a 6 12 pitch roof has 6 of rise vertical for each foot of run horizontal. Calculate the length of a rafter from the roof slope ratio of inches per foot and a building width measurement. Input the rafter span on the flat eave overhang and pitch of the roof.

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. 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. It is the length of this portion of the rafter. Click the button to calculate the stock size needed for this job.

The run of the rafter. The results are automatically fired. The rafter member will be longer. Note that this is not the actual length of the rafter.

Includes result for hip valley factor slope factor and the roof slope in degrees. Before you can mark the rafter lengths and layout check the camber of the timber. Lengths of roofing timber almost always bow slightly. For example if the roof rises 4 feet and the span is 16 feet twice the run.

Before starting the calculation we need to know some technical terms related to a pitched roof. Height of the scaffold. The rise of the rafter. Contents1 rafter of roof 2 span of roof 3 rise of roof 4 pitch of roof 5 run of roof 6 exmple 1 7 example 2 8 calculate rafter length using angle.

Pitch is the incline of the roof represented as the ratio of rise to the span twice the run. Rafter is the distance between the ridge or hip of the roof to. Determine the camber along the timbers length. The length 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 plan to have overhang etc. This calculator is to be used as an estimating tool only. If you add an eaves overhang dimension then the amount the rafter sticks passed the wall will be added to the rafter length.