The combination of two numbers are used to display or show the roof pitch.
													
																	Roof slope pitch angle. 
								
	
		
	
																	A 4 12 is a roof slope that rises by 4 inches for every 12 inches across. 
																	Roof pitch refers to the slope which the rafter creates. 
																	Roof pitch is a term describing how steep or flat your roof slope is. 
																	First convert the pitch to a slope. 
															
													
								
	
		
	
																	This measurement is best done on a bare roof because curled up roofing shingles will impair your measurement. 
																	This forms an angle of 18 5 between the horizontal section and the roof and creates a gentle incline that is seen as a midpoint between a low pitch and medium pitch roof. 
																	To find the angle of a roof in degrees convert the pitch to a slope then convert to degrees by finding the arc tangent of the slope. 
																	Roof pitch angle and slope factor charts. 
															
													
								
	
		
	
																	On blue prints architects engineers usually display the pitch of a roof in the format shown on the image where number 4 represents a rise and number 12 represents a length. 
																	Often you express roof pitch as the ratio between the rise and the run in the form of x 12. 
																	This is very useful information for many purposes especially for roof framing the slope sometimes called pitch is calibrated on speed squares. 
																	Angle the angle of a roof is the same as the roof s slope except instead of being represented as x 12 it is represented in degrees. 
															
													
								
	
		
	
																	To do this simply convert the rise and run as a fraction to a decimal form eg. 
																	Rise run rise run slope.