Polyiso Insulation vs EPS Insulation

by Rhoden RoofingSep 13, 2018

The two most common types of insulation for commercial roof systems are Polyisocyanurate (Polyiso) and Expanded Polystyrene (EPS). Both are available in a variety of thicknesses and can be used in multiple applications. Polyiso is used in new construction designs more than EPS, though EPS still has it’s advantages.

Here is a quick comparison:

*CATEGORY*	*POLYISO*	*EPS*	*WINNER*
R-VALUE PER INCH:	Higher	Lower	ISO
COST PER SHEET:	Higher	Lower	EPS
FIRE RESISTANCE:	UL class A rating	Combustible	ISO
MOISTURE RESISTANCE:	Lower	Higher	EPS
EASE OF INSTALLATION (TAPERED):	More difficult	Easier	EPS
RIGIDITY:	More rigid	Less rigid	ISO
SYSTEM APPLICATIONS:	Multiple	Multiple	TIE

So which is best?

While the winner may not be so clear, both insulation types have their pros and cons. When it’s time for a new roof, contact your local roofing contractor to help you determine which insulation is best for your building and performance needs.