So the pitch of a roof is determined by how many inches the slope rises for every 12 inches it runs horizontally.
													
																	How steep should a roof be. 
									
	
		
	
																	If a roof increases in height by three inches for every foot of horizontal run it is considered to have a 3 in 12 pitch or just a 3 pitch the primary purpose of pitching a roof is to redirect water and snow. 
																	The slope of a roof has an effect on the interior volume of a building the drainage. 
																	For most home styles roof pitches fall in a range 4 12 a moderate slope up to 8 12 fairly steep. 
																	The exact roof slope in degrees is given by the arctangent. 
															
													
									
	
		
	
																	A 4 12 pitch is around 18 5 degrees but not exactly. 
																	Thus a 4 12 pitch would be a 33 slope. 
																	Roof slope is a very important aspect and it is considered the primary factor in roof design. 
																	In degrees 10 2 in 12 or 1 in 6 is considered a minimum. 
															
													
									
	
		
	
																	Definitions vary on when a roof is considered pitched. 
																	You can also divide the rise over run multiply by 100 and get a percentage. 
																	Pitched roofs including gabled and hipped roofs are the most common types in the united states. 
																	A flat roof would have a 2 12 pitch while the average roof pitch would be between 4 12 and 9 12. 
															
													
									
	
		
	
																	9 12 20 12 steep slope. 
																	2 12 4 12 conventional slope roof. 
																	Examples of extreme slopes range from 1 4 12 almost flat to 12 12 sloping down at a perfect 45 degree angle.