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.. Pitched roof rafter lengths how to calculate the length of common rafters. once the wall plates are square and you have measured the span, you are ready to set-out and cut the common rafter lengths. these are used in almost every roof, including a gable end, lean to and hipped roof too.. The rafter section diagram (below), typical of a shed or patio cover roof, shows the (r) length measured from the outside wall to the outside face of the ridge beam. either one is acceptable, depending on which type of roof you are building, but if you are using the center-line of the ridge beam to calculate rafter length, remember to subtract.
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. the results are automatically fired. they include : the length of the rafter.. Using the appropriate roof-pitch table in a rafter cutting guide -- such as 4/12 -- determine the length of each rafter based on the correlating measurement shown for 7 feet. 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.. The roof pitch calculator calculates slope, pitch, angle and rafter lengths, based on input of rise (m) and run (r). use the diagrams on this page as a reference when inputting rise and run, and while interpreting the calculated results..
