It is very important to understand the differences in the r values of polystyrene.
													
																	1 1 2 rigid foam r value. 
									
	
		
	
																	1 844 989 1230 my account. 
																	This product typically has an r value of 3 6 to 4 0 per inch of thickness. 
																	Expanded polystyrene insulation is similar to the foam used for packing peanuts and it s typically used for insulated concrete forms also knows as icf s. 
																	The r value is an improvement over the use of a short term r value but it is insufficient for predicting the r value of extruded polystyrene foam over the life of a building particularly since building professionals expect buildings to last at least 50 years7. 
															
													
									
	
		
	
																	Multiply these by 1 5 for 1 1 2 thickness. 
																	5 8 polyisocyanurate board foil faced 7. 
																	Rigid insulation r value by comparison usually ranges from r 4 0 to 6 5 and may get as high as r 8 7 depending on the insulation material. 
																	Traditional loose fill insulation such as fiberglass or cellulose has an r value between r 2 0 and 3 5 per inch of thickness. 
															
													
									
	
		
	
																	Additional r value for a masonry wall constructed using these materials needs to add the insulating value of additional wall components typically included such as 1 solid foam polyisocyanurate r 8 extruded polystyrene r 5 expanded polystyrene r 4 or 1 of perlite r 2 7 and for an exterior air film winter no wind r 0 17 an interior. 
																	Rigid insulation is usually made up of fibrous materials or plastic foams. 
																	R value per inch of thickness. 
																	Expanded polystyrene board 3 6 to 4 avg. 
															
													
									
	
		
	
																	3 8 extruded polystyrene board 4 5 to 5 avg.