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.
Polyiso
EPS