For example while joist manufacturers regularly meet the standard l 360 criteria for code construction with 24 o c.
													
																	Floor limit l 360. 
									
	
		
	
																	Maximum deflection limits are set by building codes. 
																	Maximum deflection limits are set by building codes. 
																	Note it gives the allowable deflection based on a fractional span quantity so a larger denominator will yield less deflection. 
																	A floor joist appropriately selected to span 10 feet with an l 360 limit will deflect no more than 120 360 1 3 inches under maximum design loads. 
															
													
									
	
		
	
																	Clear span in inches l over a given number. 
																	They are expressed as a fraction. 
																	So if you have a beam 20ft long the allowable deflection limit is 20ftx12in ft 240 1. 
																	They are expressed as a fraction. 
															
													
									
	
		
	
																	And since it is small i will leave the source for where it is found here 1. 
																	Recent research has shown tile to fail under some conditions when the floor is more rigid than l 360. 
																	Please read everything on the attached photo below. 
																	If that same joist had gypsum ceiling l 240 the allowable deflection is 0 6. 
															
													
									
	
		
	
																	For example the allowable deflection of a 12ft span floor joist with plaster l 360 is 0 4 12ft divided by 360. 
																	On center systems these floors often have deflection between the joists exceeding l 360. 
																	The l stands for length. 
																	Clear span in inches l over a given number.