Figure Out Length Of Roof Rafter On Lean To

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.

Figure out length of roof rafter on lean to.

If you add an eaves overhang dimension then the amount the rafter sticks passed the wall will be added to the rafter length. 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. Includes result for hip valley factor slope factor and the roof slope in degrees. 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.

The next result is the run. See rafter run to outer wall calculator below. 1 1543 x 1 610 1 858m. Allow for ridge thickness when determining rafter run to outer wall.

As seen below the rise run and rafter length of our roofs actually make up the three sides of a right angled traingle. Here are the equations you may use to solve for the length of the slope and the rafter. 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. The length of rafter per meter of run is 1 1543.

So if we know the length of two sides of this traingle there we can use pythagoras theorem to work out the length of our rafters. Half building width minus 1 2 ridge thickness. All we do now is use a calculator to multiply 1 610 by the measurement in the book. This is the horizontal measurement from the outside of the wall to the inside of the ridge.

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 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. Print full scale rafter cut templates and birdsmouth templates fold template over rafter to mark or cut through. 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. This means that for every 1m the rafter travels horizontally the angled length of the roof will be 1 1543m.

Rise and run means that a 6 12 pitch roof has 6 of rise vertical for each foot of run horizontal.