How To Figure Cutting The Lenght Of A Roof Rafter

This is the horizontal measurement from the outside of the wall to the inside of the ridge.

How to figure cutting the lenght of a roof rafter. Rise and run means that a 6 12 pitch roof has 6 of rise vertical for each foot of run horizontal. Measure as precisely as possible down to the 1 4 inch 0 64 cm 1 8 inch 0 32 cm or 1 16 inch 0 16 cm. Rafter length using angle v r 2cos a rafter length using pitch v r 2 sqrt 1 p 2 where v overhang r roof span p pitch. On a shed roof rafter run is the distance from a ledger on the main building to the outside of an addition wall or porch carrying beam.

If you add an eaves overhang dimension then the amount the rafter sticks passed the wall will be added to the rafter length. This means that for every 1m the rafter travels horizontally the angled length of the roof will be 1 1543m. The length of rafter per meter of run is 1 1543. Before you start cutting you first need to determine how long your roof rafters need to be and the angles at which you ll cut the top and bottom of the rafter.

Includes result for hip valley factor slope factor and the roof slope in degrees. Cut the rafters to find the location of the rear lentil for the rafters use a framing square. The length of the rafter is given from the long point of the ridge cut at the top down along the top edge the board to the same plumb cut on the rafter s notch. 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.

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. We need to adjust the total run 73 inches in our example by subtracting 1 1 2 inches the full thickness of the ledger adjusted run 71 1 2 inches. 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. Cut one end of each 2 x 8 rafter to get the necessary length desired.

1 1543 x 1 610 1 858m. Use a tape measure to measure the entire width of your building. All we do now is use a calculator to multiply 1 610 by the measurement in the book. Calculate the length of a rafter from the roof slope ratio of inches per foot and a building width measurement.

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.