Figure Out Length Of Roof Rafter On Lean To

If you are calculating rafter length from the center of the ridge beam as shown below you will need to subtract half of the thickness of the ridge beam from the top end of the rafter.

Figure out length of roof rafter on lean to. This means that for every 1m the rafter travels horizontally the angled length of the roof will be 1 1543m. For example if the ridge beam is 1 5 inches thick subtract 3 4 of an inch from the overall rafter length. In other words if there is a 1 1 2 ridge board nailed into the wall and the width of the lean to is 96 then the run will be 94 1 2 96 1 1 2 94 1 2. See rafter run to outer wall calculator below.

The run for a lean to shed rafter ending into a wall should account for the ridge board nailed into the wall where the tops of the rafters rest into. Rafter rise run this formula is from the pythagorean theorem rise run pitch use this when you express the pitch in percent pitch tan angle use this when you express the angle of the roof pitch in degrees. This is the horizontal measurement from the outside of the wall to the inside 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.

All we do now is use a calculator to multiply 1 610 by the measurement in the book. 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. Rise and run means that a 6 12 pitch roof has 6 of rise vertical for each foot of run horizontal. 1 1543 x 1 610 1 858m.

The length of rafter per meter of run is 1 1543. Includes result for hip valley factor slope factor and the roof slope in degrees. Print full scale rafter cut templates and birdsmouth templates fold template over rafter to mark or cut through. Half building width minus 1 2 ridge thickness.

Calculate the length of a rafter from the roof slope ratio of inches per foot and a building width measurement. Allow for ridge thickness when determining rafter run to outer wall. 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. Here are the equations you may use to solve for the length of the slope and the rafter.

As seen below the rise run and rafter length of our roofs actually make up the three sides of a right angled traingle.