This video will show you how to figure length and cut a common rafter for a gable roof using a framing square.
Formula to cut and stack a roof.
There is an easy trick for drawing out the hole.
All roof rafters should be identical so follow the same steps to measure the plumb cut tail cut and birdsmouth cut.
In the imperial unit of measurements the slope is expressed with the rise and run.
This article series explains how to use a framing square and in companion articles we give examples just about every possible way to figure out any or all roof stair or other building framing dimensions and measurements including problems such as figuring the roof area width length and roof or stairway slope rise.
Hold the pipe in place and run it up close to the roof decking.
How to use a framing square to lay out the birds mouth cut on a rafter.
To begin with pieceworkers try to avoid cutting one piece at a time.
With the saw bevel angle set to 45 cutting hips and creepers at the plumb cut angle will produce correct side angles.
See saw miter and blade angle settings.
I couldn t cut a piece then put it in place to see if it fit it just had to be right the first time.
Then shine a bright flashlight through the pipe from the.
The actual stack portion of this cut and stack went quickly the bulk of the roof was up in a day.
Next use these calculations to determine how many rafters you ll need for your roof and cut them to size.
Depending on the size of your structure you will need to cut several or many more.
The problem is that a 3 inch round pipe needs an oval hole in a sloped roof.
To frame a roof start by choosing a roof style like a frame or gabled.
To demonstrate just how easy roof framing can be with a little practice i ll describe how to cut and stack a gable roof the way pieceworkers do it.
If using a circular saw or compound miter saw set saw bevel angle to 45 to obtain creeper and hip side angles.
Increase your roof framing knowledge and understanding as you follow veteran roof cutter will holladay through the process of calculating two custom home roofs.
At this point you ve cut 1 roof rafter.
By slope angle formula steepness can be obtained by dividing vertical rise by horizontal span.
In the complicated roof a cut and stack workbook you ll see the principles of holladay s a roof cutter s secrets come alive.
They ll build a pair of simple horses out of 2x stock so that they can stack the rafters on edge and.
Then gather your measurements by calculating the run rise and length of each rafter segment in feet and the pitch of your roof in inches.
When plumbing pipes and chimneys have to go through sloped roofs they are always cut fairly large just to make sure that the pipe will pass through.
The number of rafters needed will be determined by the length of your roof.
In civil engineering the slope is the numerical measure of the steepness of a roof.
